Energy transformations in the universe over time are characterized by various kinds of potential energy that has been available since the Big Bang later being "released" (transformed to more active types of energy such as kinetic or radiant energy) when a triggering mechanism is available. Familiar examples of such processes include nuclear decay, in which energy is released that was originally "stored" in heavy isotopes (such as uranium and thorium), by nucleosynthesis, a process ultimately using the gravitational potential energy released from the gravitational collapse of supernovae, to store energy in the creation of these heavy elements before they were incorporated into the solar system and the Earth. This energy is triggered and released in nuclear fission bombs or in civil nuclear power generation. Similarly, in the case of a chemical explosion, chemical potential energy is transformed to kinetic energy and thermal energy in a very short time. Yet another example is that of a pendulum. At its highest points the kinetic energy is zero and the gravitational potential energy is at maximum. At its lowest point the kinetic energy is at maximum and is equal to the decrease of potential energy. If one (unrealistically) assumes that there is no friction or other losses, the conversion of energy between these processes would be perfect, and the pendulum would continue swinging forever.


Energy gives rise to weight when it is trapped in a system with zero momentum, where it can be weighed. It is also equivalent to mass, and this mass is always associated with it. Mass is also equivalent to a certain amount of energy, and likewise always appears associated with it, as described in mass-energy equivalence. The formula E = mc², derived by Albert Einstein (1905) quantifies the relationship between rest-mass and rest-energy within the concept of special relativity. In different theoretical frameworks, similar formulas were derived by J. J. Thomson (1881), Henri Poincaré (1900), Friedrich Hasenöhrl (1904) and others (see Mass-energy equivalence#History for further information).


Matter may be converted to energy (and vice versa), but mass cannot ever be destroyed; rather, mass/energy equivalence remains a constant for both the matter and the energy, during any process when they are converted into each other. However, since  is extremely large relative to ordinary human scales, the conversion of ordinary amount of matter (for example, 1 kg) to other forms of energy (such as heat, light, and other radiation) can liberate tremendous amounts of energy (~ joules = 21 megatons of TNT), as can be seen in nuclear reactors and nuclear weapons. Conversely, the mass equivalent of a unit of energy is minuscule, which is why a loss of energy (loss of mass) from most systems is difficult to measure by weight, unless the energy loss is very large. Examples of energy transformation into matter (i.e., kinetic energy into particles with rest mass) are found in high-energy nuclear physics.


Thermodynamics divides energy transformation into two kinds: reversible processes and irreversible processes. An irreversible process is one in which energy is dissipated (spread) into empty energy states available in a volume, from which it cannot be recovered into more concentrated forms (fewer quantum states), without degradation of even more energy. A reversible process is one in which this sort of dissipation does not happen. For example, conversion of energy from one type of potential field to another, is reversible, as in the pendulum system described above. In processes where heat is generated, quantum states of lower energy, present as possible excitations in fields between atoms, act as a reservoir for part of the energy, from which it cannot be recovered, in order to be converted with 100% efficiency into other forms of energy. In this case, the energy must partly stay as heat, and cannot be completely recovered as usable energy, except at the price of an increase in some other kind of heat-like increase in disorder in quantum states, in the universe (such as an expansion of matter, or a randomisation in a crystal).


As the universe evolves in time, more and more of its energy becomes trapped in irreversible states (i.e., as heat or other kinds of increases in disorder). This has been referred to as the inevitable thermodynamic heat death of the universe. In this heat death the energy of the universe does not change, but the fraction of energy which is available to do work through a heat engine, or be transformed to other usable forms of energy (through the use of generators attached to heat engines), grows less and less.


According to conservation of energy, energy can neither be created (produced) nor destroyed by itself. It can only be transformed. The total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system. Energy is subject to a strict global conservation law; that is, whenever one measures (or calculates) the total energy of a system of particles whose interactions do not depend explicitly on time, it is found that the total energy of the system always remains constant.


This law is a fundamental principle of physics. As shown rigorously by Noether's theorem, the conservation of energy is a mathematical consequence of translational symmetry of time, a property of most phenomena below the cosmic scale that makes them independent of their locations on the time coordinate. Put differently, yesterday, today, and tomorrow are physically indistinguishable. This is because energy is the quantity which is canonical conjugate to time. This mathematical entanglement of energy and time also results in the uncertainty principle - it is impossible to define the exact amount of energy during any definite time interval. The uncertainty principle should not be confused with energy conservation - rather it provides mathematical limits to which energy can in principle be defined and measured.


In particle physics, this inequality permits a qualitative understanding of virtual particles which carry momentum, exchange by which and with real particles, is responsible for the creation of all known fundamental forces (more accurately known as fundamental interactions). Virtual photons (which are simply lowest quantum mechanical energy state of photons) are also responsible for electrostatic interaction between electric charges (which results in Coulomb law), for spontaneous radiative decay of exited atomic and nuclear states, for the Casimir force, for van der Waals bond forces and some other observable phenomena.


Energy transfer can be considered for the special case of systems which are closed to transfers of matter. The portion of the energy which is transferred by conservative forces over a distance is measured as the work the source system does on the receiving system. The portion of the energy which does not do work during the transfer is called heat.[note 4] Energy can be transferred between systems in a variety of ways. Examples include the transmission of electromagnetic energy via photons, physical collisions which transfer kinetic energy,[note 5] and the conductive transfer of thermal energy.


The first law of thermodynamics asserts that energy (but not necessarily thermodynamic free energy) is always conserved and that heat flow is a form of energy transfer. For homogeneous systems, with a well-defined temperature and pressure, a commonly used corollary of the first law is that, for a system subject only to pressure forces and heat transfer (e.g., a cylinder-full of gas) without chemical changes, the differential change in the internal energy of the system (with a gain in energy signified by a positive quantity) is given as


This principle is vitally important to understanding the behaviour of a quantity closely related to energy, called entropy. Entropy is a measure of evenness of a distribution of energy between parts of a system. When an isolated system is given more degrees of freedom (i.e., given new available energy states that are the same as existing states), then total energy spreads over all available degrees equally without distinction between "new" and "old" degrees. This mathematical result is called the second law of thermodynamics.


East Prussia enclosed the bulk of the ancestral lands of the Baltic Old Prussians. During the 13th century, the native Prussians were conquered by the crusading Teutonic Knights. The indigenous Balts who survived the conquest were gradually converted to Christianity. Because of Germanization and colonisation over the following centuries, Germans became the dominant ethnic group, while Poles and Lithuanians formed minorities. From the 13th century, East Prussia was part of the monastic state of the Teutonic Knights. After the Second Peace of Thorn in 1466 it became a fief of the Kingdom of Poland. In 1525, with the Prussian Homage, the province became the Duchy of Prussia. The Old Prussian language had become extinct by the 17th or early 18th century.


Because the duchy was outside of the core Holy Roman Empire, the prince-electors of Brandenburg were able to proclaim themselves King of Prussia beginning in 1701. After the annexation of most of western Royal Prussia in the First Partition of the Polish-Lithuanian Commonwealth in 1772, eastern (ducal) Prussia was connected by land with the rest of the Prussian state and was reorganized as a province the following year (1773). Between 1829 and 1878, the Province of East Prussia was joined with West Prussia to form the Province of Prussia.


The Kingdom of Prussia became the leading state of the German Empire after its creation in 1871. However, the Treaty of Versailles following World War I granted West Prussia to Poland and made East Prussia an exclave of Weimar Germany (the new Polish Corridor separating East Prussia from the rest of Germany), while the Memel Territory was detached and was annexed by Lithuania in 1923. Following Nazi Germany's defeat in World War II in 1945, war-torn East Prussia was divided at Joseph Stalin's insistence between the Soviet Union (the Kaliningrad Oblast in the Russian SFSR and the constituent counties of the Klaipėda Region in the Lithuanian SSR) and the People's Republic of Poland (the Warmian-Masurian Voivodeship). The capital city Königsberg was renamed Kaliningrad in 1946. The German population of the province was largely evacuated during the war or expelled shortly thereafter in the expulsion of Germans after World War II. An estimated 300,000 (around one fifth of the population) died either in war time bombings raids or in the battles to defend the province.[citation needed]


Upon the invitation of Duke Konrad I of Masovia, the Teutonic Knights took possession of Prussia in the 13th century and created a monastic state to administer the conquered Old Prussians. Local Old-Prussian (north) and Polish (south) toponyms were gradually Germanised. The Knights' expansionist policies, including occupation of Polish Pomerania with Gdańsk/Danzig and western Lithuania, brought them into conflict with the Kingdom of Poland and embroiled them in several wars, culminating in the Polish-Lithuanian-Teutonic War, whereby the united armies of Poland and Lithuania, defeated the Teutonic Order at the Battle of Grunwald (Tannenberg) in 1410. Its defeat was formalised in the Second Treaty of Thorn in 1466 ending the Thirteen Years' War, and leaving the former Polish region Pomerania/Pomerelia under Polish control. Together with Warmia it formed the province of Royal Prussia. Eastern Prussia remained under the Knights, but as a fief of Poland. 1466 and 1525 arrangements by kings of Poland were not verified by the Holy Roman Empire as well as the previous gains of the Teutonic Knights were not verified.


The Teutonic Order lost eastern Prussia when Grand Master Albert of Brandenburg-Ansbach converted to Lutheranism and secularized the Prussian branch of the Teutonic Order in 1525. Albert established himself as the first duke of the Duchy of Prussia and a vassal of the Polish crown by the Prussian Homage. Walter von Cronberg, the next Grand Master, was enfeoffed with the title to Prussia after the Diet of Augsburg in 1530, but the Order never regained possession of the territory. In 1569 the Hohenzollern prince-electors of the Margraviate of Brandenburg became co-regents with Albert's son, the feeble-minded Albert Frederick.


The Administrator of Prussia, the grandmaster of the Teutonic Order Maximilian III, son of emperor Maximilian II died in 1618. When Maximilian died, Albert's line died out, and the Duchy of Prussia passed to the Electors of Brandenburg, forming Brandenburg-Prussia. Taking advantage of the Swedish invasion of Poland in 1655, and instead of fulfilling his vassal's duties towards the Polish Kingdom, by joining forces with the Swedes and subsequent treaties of Wehlau, Labiau, and Oliva, Elector and Duke Frederick William succeeded in revoking king of Poland's sovereignty over the Duchy of Prussia in 1660. The absolutist elector also subdued the noble estates of Prussia.


Although Brandenburg was a part of the Holy Roman Empire, the Prussian lands were not within the Holy Roman Empire and were with the administration by the Teutonic Order grandmasters under jurisdiction of the Emperor. In return for supporting Emperor Leopold I in the War of the Spanish Succession, Elector Frederick III was allowed to crown himself "King in Prussia" in 1701. The new kingdom ruled by the Hohenzollern dynasty became known as the Kingdom of Prussia. The designation "Kingdom of Prussia" was gradually applied to the various lands of Brandenburg-Prussia. To differentiate from the larger entity, the former Duchy of Prussia became known as Altpreußen ("Old Prussia"), the province of Prussia, or "East Prussia".


Approximately one-third of East Prussia's population died in the plague and famine of 1709–1711, including the last speakers of Old Prussian. The plague, probably brought by foreign troops during the Great Northern War, killed 250,000 East Prussians, especially in the province's eastern regions. Crown Prince Frederick William I led the rebuilding of East Prussia, founding numerous towns. Thousands of Protestants expelled from the Archbishopric of Salzburg were allowed to settle in depleted East Prussia. The province was overrun by Imperial Russian troops during the Seven Years' War.


In the 1772 First Partition of Poland, the Prussian king Frederick the Great annexed neighboring Royal Prussia, i.e. the Polish voivodeships of Pomerania (Gdańsk Pomerania or Pomerelia), Malbork, Chełmno and the Prince-Bishopric of Warmia, thereby bridging the "Polish Corridor" between his Prussian and Farther Pomeranian lands and cutting remaining Poland off the Baltic Coast. The territory of Warmia was incorporated into the lands of former Ducal Prussia, which, by administrative deed of 31 January 1773 were named East Prussia. The former Polish Pomerelian lands beyond the Vistula River together with Malbork and Chełmno Land formed the Province of West Prussia with its capital at Marienwerder (Kwidzyn). The Polish Partition Sejm ratified the cession on 30 September 1773, whereafter Frederick officially went on to call himself a King "of" Prussia.


After the disastrous defeat of the Prussian Army at the Battle of Jena-Auerstedt in 1806, Napoleon occupied Berlin and had the officials of the Prussian General Directory swear an oath of allegiance to him, while King Frederick William III and his consort Louise fled via Königsberg and the Curonian Spit to Memel. The French troops immediately took up pursuit but were delayed in the Battle of Eylau on 9 February 1807 by an East Prussian contingent under General Anton Wilhelm von L'Estocq. Napoleon had to stay at the Finckenstein Palace, but in May, after a siege of 75 days, his troops led by Marshal François Joseph Lefebvre were able to capture the city Danzig, which had been tenaciously defended by General Count Friedrich Adolf von Kalkreuth. On 14 June, Napoleon ended the War of the Fourth Coalition with his victory at the Battle of Friedland. Frederick William and Queen Louise met with Napoleon for peace negotiations, and on 9 July the Prussian king signed the Treaty of Tilsit.


The succeeding Prussian reforms instigated by Heinrich Friedrich Karl vom und zum Stein and Karl August von Hardenberg included the implementation of an Oberlandesgericht appellation court at Königsberg, a municipal corporation, economic freedom as well as emancipation of the serfs and Jews. In the course of the Prussian restoration by the 1815 Congress of Vienna, the East Prussian territories were re-arranged in the Regierungsbezirke of Gumbinnen and Königsberg. From 1905, the southern districts of East Prussia formed the separate Regierungsbezirk of Allenstein. East and West Prussia were first united in personal union in 1824, and then merged in a real union in 1829 to form the Province of Prussia. The united province was again split into separate East and West Prussian provinces in 1878.


The population of the province in 1900 was 1,996,626 people, with a religious makeup of 1,698,465 Protestants, 269,196 Roman Catholics, and 13,877 Jews. The Low Prussian dialect predominated in East Prussia, although High Prussian was spoken in Warmia. The numbers of Masurians, Kursenieki and Prussian Lithuanians decreased over time due to the process of Germanization. The Polish-speaking population concentrated in the south of the province (Masuria and Warmia) and all German geographic atlases at the start of 20th century showed the southern part of East Prussia as Polish with the number of Poles estimated at the time to be 300,000. Kursenieki inhabited the areas around the Curonian lagoon, while Lithuanian-speaking Prussians concentrated in the northeast in (Lithuania Minor). The Old Prussian ethnic group became completely Germanized over time and the Old Prussian language died out in the 18th century.


At the beginning of World War I, East Prussia became a theatre of war when the Russian Empire invaded the country. The Russian Army encountered at first little resistance because the bulk of the German Army had been directed towards the Western Front according to the Schlieffen Plan. Despite early success and the capture of the towns of Rastenburg and Gumbinnen, in the Battle of Tannenberg in 1914 and the Second Battle of the Masurian Lakes in 1915, the Russians were decisively defeated and forced to retreat. The Russians were followed by the German Army advancing into Russian territory.


With the forced abdication of Emperor William II in 1918, Germany became a republic. Most of West Prussia and the former Prussian Province of Posen, territories annexed by Prussia in the 18th century Partitions of Poland, were ceded to the Second Polish Republic according to the Treaty of Versailles. East Prussia became an exclave, being separated from mainland Germany. After the Treaty of Versailles, East Prussia was separated from Germany as an exclave; the Memelland was also separated from the province. Because most of West Prussia became part of the Second Polish Republic as the Polish Corridor, the formerly West Prussian Marienwerder region became part of East Prussia (as Regierungsbezirk Westpreußen). Also Soldau district in Allenstein region was part of Second Polish Republic. The Seedienst Ostpreußen was established to provide an independent transport service to East Prussia.


Erich Koch headed the East Prussian Nazi party from 1928. He led the district from 1932. This period was characterized by efforts to collectivize the local agriculture and ruthlessness in dealing with his critics inside and outside the Party. He also had long-term plans for mass-scale industrialization of the largely agricultural province. These actions made him unpopular among the local peasants. In 1932 the local paramilitary SA had already started to terrorise their political opponents. On the night of 31 July 1932 there was a bomb attack on the headquarters of the Social Democrats in Königsberg, the Otto-Braun-House. The Communist politician Gustav Sauf was killed; the executive editor of the Social Democrat "Königsberger Volkszeitung", Otto Wyrgatsch, and the German People's Party politician Max von Bahrfeldt were severely injured. Members of the Reichsbanner were attacked and the local Reichsbanner Chairman of Lötzen, Kurt Kotzan, was murdered on 6 August 1932.


Through publicly funded emergency relief programs concentrating on agricultural land-improvement projects and road construction, the "Erich Koch Plan" for East Prussia allegedly made the province free of unemployment; on August 16, 1933 Koch reported to Hitler that unemployment had been banished entirely from East Prussia, a feat that gained admiration throughout the Reich. Koch's industrialization plans led him into conflict with R. Walther Darré, who held the office of the Reich Peasant Leader (Reichsbauernführer) and Minister of Agriculture. Darré, a neopaganist rural romantic, wanted to enforce his vision of an agricultural East Prussia. When his "Land" representatives challenged Koch's plans, Koch had them arrested.


In 1938 the Nazis altered about one-third of the toponyms of the area, eliminating, Germanizing, or simplifying a number of Old Prussian names, as well as those Polish or Lithuanian names originating from colonists and refugees to Prussia during and after the Protestant Reformation. More than 1,500 places were ordered to be renamed by 16 July 1938 following a decree issued by Gauleiter and Oberpräsident Erich Koch and initiated by Adolf Hitler. Many who would not cooperate with the rulers of Nazi Germany were sent to concentration camps and held prisoner there until their death or liberation.


In 1939 East Prussia had 2.49 million inhabitants, 85% of them ethnic Germans, the others Poles in the south who, according to Polish estimates numbered in the interwar period around 300,000-350,000, the Latvian speaking Kursenieki, and Lietuvininkai who spoke Lithuanian in the northeast. Most German East Prussians, Masurians, Kursieniki, and Lietuvininkai were Lutheran, while the population of Ermland was mainly Roman Catholic due to the history of its bishopric. The East Prussian Jewish Congregation declined from about 9,000 in 1933 to 3,000 in 1939, as most fled from Nazi rule. Those who remained were later deported and killed in the Holocaust.


In 1939 the Regierungsbezirk Zichenau was annexed by Germany and incorporated into East Prussia. Parts of it were transferred to other regions, e.g. Suwałki to Regierungsbezirk Gumbinnen and Soldau to Regierungsbezirk Allenstein. Despite Nazi propaganda presenting all of the regions annexed as possessing significant German populations that wanted reunification with Germany, the Reich's statistics of late 1939 show that only 31,000 out of 994,092 people in this territory were ethnic Germans.[citation needed]


Following Nazi Germany's defeat in World War II in 1945, East Prussia was partitioned between Poland and the Soviet Union according to the Potsdam Conference. Southern East Prussia was placed under Polish administration, while northern East Prussia was divided between the Soviet republics of Russia (the Kaliningrad Oblast) and Lithuania (the constituent counties of the Klaipėda Region). The city of Königsberg was renamed Kaliningrad in 1946. The German population of the province largely evacuated during the war, but several hundreds of thousands died during the years 1944–46 and the remainder were subsequently expelled.


Shortly after the end of the war in May 1945, Germans who had fled in early 1945 tried to return to their homes in East Prussia. An estimated number of 800,000 Germans were living in East Prussia during the summer of 1945. Many more were prevented from returning,[citation needed] and the German population of East Prussia was almost completely expelled by the communist regimes. During the war and for some time thereafter 45 camps were established for about 200,000-250,000 forced labourers, the vast majority of whom were deported to the Soviet Union, including the Gulag camp system. The largest camp with about 48,000 inmates was established at Deutsch Eylau (Iława). Orphaned children who were left behind in the zone occupied by the Soviet Union were referred to as Wolf children.


Representatives of the Polish government officially took over the civilian administration of the southern part of East Prussia on 23 May 1945. Subsequently Polish expatriates from Polish lands annexed by the Soviet Union as well as Ukrainians and Lemkos from southern Poland, expelled in Operation Vistula in 1947, were settled in the southern part of East Prussia, now the Polish Warmian-Masurian Voivodeship. In 1950 the Olsztyn Voivodeship counted 689,000 inhabitants, 22.6% of them coming from areas annexed by the Soviet Union, 10% Ukrainians, and 18.5% of them pre-war inhabitants. The remaining pre-war population was treated as Germanized Poles and a policy of re-Polonization was pursued throughout the country Most of these "Autochthones" chose to emigrate to West Germany from the 1950s through 1970s (between 1970 and 1988 55,227 persons from Warmia and Masuria moved to Western Germany). Local toponyms were Polonised by the Polish Commission for the Determination of Place Names.


In April 1946, northern East Prussia became an official province of the Russian SFSR as the "Kyonigsbergskaya Oblast", with the Memel Territory becoming part of the Lithuanian SSR. In June 1946 114,070 German and 41,029 Soviet citizens were registered in the Oblast, with an unknown number of disregarded unregistered persons. In July of that year, the historic city of Königsberg was renamed Kaliningrad to honour Mikhail Kalinin and the area named the Kaliningrad Oblast. Between 24 August and 26 October 1948 21 transports with in total 42,094 Germans left the Oblast to the Soviet Occupation Zone (which became East Germany). The last remaining Germans left in November 1949 (1,401 persons) and January 1950 (7 persons).


A similar fate befell the Curonians who lived in the area around the Curonian Lagoon. While many fled from the Red Army during the evacuation of East Prussia, Curonians that remained behind were subsequently expelled by the Soviet Union. Only 219 lived along the Curonian Spit in 1955. Many had German names such as Fritz or Hans, a cause for anti-German discrimination. The Soviet authorities considered the Curonians fascists. Because of this discrimination, many immigrated to West Germany in 1958, where the majority of Curonians now live.


After the expulsion of the German population ethnic Russians, Belarusians, and Ukrainians were settled in the northern part. In the Soviet part of the region, a policy of eliminating all remnants of German history was pursued. All German place names were replaced by new Russian names. The exclave was a military zone, which was closed to foreigners; Soviet citizens could only enter with special permission. In 1967 the remnants of Königsberg Castle were demolished on the orders of Leonid Brezhnev to make way for a new "House of the Soviets".


Although the 1945–1949 expulsion of Germans from the northern part of former East Prussia was often conducted in a violent and aggressive way by Soviet officials, the present Russian inhabitants of the Kaliningrad Oblast have much less animosity towards Germans. German names have been revived in commercial Russian trade and there is sometimes talk of reverting Kaliningrad's name to its historic name of Königsberg. The city centre of Kaliningrad was completely rebuilt, as British bombs in 1944 and the Soviet siege in 1945 had left it in nothing but ruins.


Since 1875, with the strengthening of self-rule, the urban and rural districts (Kreise) within each province (sometimes within each governorate) formed a corporation with common tasks and assets (schools, traffic installations, hospitals, cultural institutions, jails etc.) called the Provinzialverband (provincial association). Initially the assemblies of the urban and rural districts elected representatives for the provincial diets (Provinziallandtage), which were thus indirectly elected. As of 1919 the provincial diets (or as to governorate diets, the so-called Kommunallandtage) were directly elected by the citizens of the provinces (or governorates, respectively). These parliaments legislated within the competences transferred to the provincial associations. The provincial diet of East Prussia elected a provincial executive body (government), the provincial committee (Provinzialausschuss), and a head of province, the Landeshauptmann ("Land Captain"; till the 1880s titled Landdirektor, land director).


The Ottoman Empire (/ˈɒtəmən/; Ottoman Turkish: دَوْلَتِ عَلِيّهٔ عُثمَانِیّه Devlet-i Aliyye-i Osmâniyye, Modern Turkish: Osmanlı İmparatorluğu or Osmanlı Devleti), also known as the Turkish Empire, Ottoman Turkey or Turkey, was an empire founded in 1299 by Oghuz Turks under Osman I in northwestern Anatolia. After conquests in the Balkans by Murad I between 1362 and 1389, the Ottoman sultanate was transformed into a transcontinental empire and claimant to the caliphate. The Ottomans ended the Byzantine Empire with the 1453 conquest of Constantinople by Mehmed the Conqueror.


During the 16th and 17th centuries, in particular at the height of its power under the reign of Suleiman the Magnificent, the Ottoman Empire was a multinational, multilingual empire controlling much of Southeast Europe, Western Asia, the Caucasus, North Africa, and the Horn of Africa. At the beginning of the 17th century the empire contained 32 provinces and numerous vassal states. Some of these were later absorbed into the Ottoman Empire, while others were granted various types of autonomy during the course of centuries.[dn 4]


With Constantinople as its capital and control of lands around the Mediterranean basin, the Ottoman Empire was at the centre of interactions between the Eastern and Western worlds for six centuries. Following a long period of military setbacks against European powers, the Ottoman Empire gradually declined into the late nineteenth century. The empire allied with Germany in the early 20th century, with the imperial ambition of recovering its lost territories, joining in World War I to achieve this ambition on the side of Germany and the Central Powers. While the Empire was able to largely hold its own during the conflict, it was struggling with internal dissent, especially with the Arab Revolt in its Arabian holdings. Starting before the war, but growing increasingly common and violent during it, major atrocities were committed by the Ottoman government against the Armenians, Assyrians and Pontic Greeks. The Empire's defeat and the occupation of part of its territory by the Allied Powers in the aftermath of World War I resulted in the emergence of a new state, Turkey, in the Ottoman Anatolian heartland following the Turkish War of Independence, as well as the founding of modern Balkan and Middle Eastern states and the partitioning of the Ottoman Empire.


The word Ottoman is a historical anglicisation of the name of Osman I, the founder of the Empire and of the ruling House of Osman (also known as the Ottoman dynasty). Osman's name in turn was derived from the Persian form of the name ʿUthmān عثمان of ultimately Arabic origin. In Ottoman Turkish, the empire was referred to as Devlet-i ʿAliyye-yi ʿOsmâniyye (دَوْلَتِ عَلِيّهٔ عُثمَانِیّه), (literally "The Supreme State of the Ottomans") or alternatively Osmanlı Devleti (عثمانلى دولتى).[dn 5] In Modern Turkish, it is known as Osmanlı İmparatorluğu ("Ottoman Empire") or Osmanlı Devleti ("The Ottoman State").


Ertuğrul, the father of Osman I (founder of the Ottoman Empire), arrived in Anatolia from Merv (Turkmenistan) with 400 horsemen to aid the Seljuks of Rum against the Byzantines. After the demise of the Turkish Seljuk Sultanate of Rum in the 14th century, Anatolia was divided into a patchwork of independent, mostly Turkish states, the so-called Ghazi emirates. One of the emirates was led by Osman I (1258–1326), from whom the name Ottoman is derived. Osman I extended the frontiers of Turkish settlement toward the edge of the Byzantine Empire. It is not well understood how the early Ottomans came to dominate their neighbours, as the history of medieval Anatolia is still little known.


In the century after the death of Osman I, Ottoman rule began to extend over the Eastern Mediterranean and the Balkans. Osman's son, Orhan, captured the northwestern Anatolian city of Bursa in 1324, and made it the new capital of the Ottoman state. This Ottoman conquest meant the loss of Byzantine control over northwestern Anatolia. The important city of Thessaloniki was captured from the Venetians in 1387. The Ottoman victory at Kosovo in 1389 effectively marked the end of Serbian power in the region, paving the way for Ottoman expansion into Europe. The Battle of Nicopolis in 1396, widely regarded as the last large-scale crusade of the Middle Ages, failed to stop the advance of the victorious Ottoman Turks.


With the extension of Turkish dominion into the Balkans, the strategic conquest of Constantinople became a crucial objective. The empire had managed to control nearly all former Byzantine lands surrounding the city, but in 1402 the Byzantines were temporarily relieved when the Turco-Mongol leader Timur, founder of the Timurid Empire, invaded Anatolia from the east. In the Battle of Ankara in 1402, Timur defeated the Ottoman forces and took Sultan Bayezid I as a prisoner, throwing the empire into disorder. The ensuing civil war lasted from 1402 to 1413 as Bayezid's sons fought over succession. It ended when Mehmed I emerged as the sultan and restored Ottoman power, bringing an end to the Interregnum, also known as the Fetret Devri.


Part of the Ottoman territories in the Balkans (such as Thessaloniki, Macedonia and Kosovo) were temporarily lost after 1402 but were later recovered by Murad II between the 1430s and 1450s. On 10 November 1444, Murad II defeated the Hungarian, Polish, and Wallachian armies under Władysław III of Poland (also King of Hungary) and John Hunyadi at the Battle of Varna, the final battle of the Crusade of Varna, although Albanians under Skanderbeg continued to resist. Four years later, John Hunyadi prepared another army (of Hungarian and Wallachian forces) to attack the Turks but was again defeated by Murad II at the Second Battle of Kosovo in 1448.


The son of Murad II, Mehmed the Conqueror, reorganized the state and the military, and conquered Constantinople on 29 May 1453. Mehmed allowed the Orthodox Church to maintain its autonomy and land in exchange for accepting Ottoman authority. Because of bad relations between the states of western Europe and the later Byzantine Empire, the majority of the Orthodox population accepted Ottoman rule as preferable to Venetian rule. Albanian resistance was a major obstacle to Ottoman expansion on the Italian peninsula.


Suleiman the Magnificent (1520–1566) captured Belgrade in 1521, conquered the southern and central parts of the Kingdom of Hungary as part of the Ottoman–Hungarian Wars,[not in citation given] and, after his historical victory in the Battle of Mohács in 1526, he established Turkish rule in the territory of present-day Hungary (except the western part) and other Central European territories. He then laid siege to Vienna in 1529, but failed to take the city. In 1532, he made another attack on Vienna, but was repulsed in the Siege of Güns. Transylvania, Wallachia and, intermittently, Moldavia, became tributary principalities of the Ottoman Empire. In the east, the Ottoman Turks took Baghdad from the Persians in 1535, gaining control of Mesopotamia and naval access to the Persian Gulf. In 1555, the Caucasus became officially partitioned for the first time between the Safavids and the Ottomans, a status quo that would remain until the end of the Russo-Turkish War (1768–74). By this partitioning of the Caucasus as signed in the Peace of Amasya, Western Armenia, and Western Georgia fell into Ottoman hands, while Dagestan, Eastern Armenia, Eastern Georgia, and Azerbaijan remained Persian.


France and the Ottoman Empire, united by mutual opposition to Habsburg rule, became strong allies. The French conquests of Nice (1543) and Corsica (1553) occurred as a joint venture between the forces of the French king Francis I and Suleiman, and were commanded by the Ottoman admirals Barbarossa Hayreddin Pasha and Turgut Reis. A month prior to the siege of Nice, France supported the Ottomans with an artillery unit during the 1543 Ottoman conquest of Esztergom in northern Hungary. After further advances by the Turks, the Habsburg ruler Ferdinand officially recognized Ottoman ascendancy in Hungary in 1547.


The stagnation and decline, Stephen Lee argues, was relentless after the death of Suleiman in 1566, interrupted by a few short revivals or reform and recovery. The decline gathered speed so that the Empire in 1699 was, "a mere shadow of that which intimidated East and West alike in 1566." Although there are dissenting scholars, most historians point to "degenerate Sultans, incompetent Grand Viziers, debilitated and ill-equipped armies, corrupt officials, avaricious speculators, grasping enemies, and treacherous friends." The main cause was a failure of leadership, as Lee argues the first 10 sultans from 1292 to 1566, with one exception, had performed admirably. The next 13 sultans from 1566 to 1703, with two exceptions, were lackadaisical or incompetent rulers, says Lee. In a highly centralized system, the failure at the center proved fatal. A direct result was the strengthening of provincial elites who increasingly ignored Constantinople. Secondly the military strength of European enemies grew stronger and stronger, while the Ottoman armies and arms scarcely improved. Finally the Ottoman economic system grew distorted and impoverished, as war caused inflation, world trade moved in other directions, and the deterioration of law and order made economic progress difficult.


The effective military and bureaucratic structures of the previous century came under strain during a protracted period of misrule by weak Sultans. The Ottomans gradually fell behind the Europeans in military technology as the innovation that fed the Empire's forceful expansion became stifled by growing religious and intellectual conservatism. But in spite of these difficulties, the Empire remained a major expansionist power until the Battle of Vienna in 1683, which marked the end of Ottoman expansion into Europe.


The discovery of new maritime trade routes by Western European states allowed them to avoid the Ottoman trade monopoly. The Portuguese discovery of the Cape of Good Hope in 1488 initiated a series of Ottoman-Portuguese naval wars in the Indian Ocean throughout the 16th century. The Somali Muslim Ajuran Empire, allied with the Ottomans, defied the Portuguese economic monopoly in the Indian Ocean by employing a new coinage which followed the Ottoman pattern, thus proclaiming an attitude of economic independence in regard to the Portuguese.


In southern Europe, a Catholic coalition led by Philip II of Spain won a victory over the Ottoman fleet at the Battle of Lepanto (1571). It was a startling, if mostly symbolic, blow to the image of Ottoman invincibility, an image which the victory of the Knights of Malta against the Ottoman invaders in the 1565 Siege of Malta had recently set about eroding. The battle was far more damaging to the Ottoman navy in sapping experienced manpower than the loss of ships, which were rapidly replaced. The Ottoman navy recovered quickly, persuading Venice to sign a peace treaty in 1573, allowing the Ottomans to expand and consolidate their position in North Africa.


By contrast, the Habsburg frontier had settled somewhat, a stalemate caused by a stiffening of the Habsburg defences. The Long War against Habsburg Austria (1593–1606) created the need for greater numbers of Ottoman infantry equipped with firearms, resulting in a relaxation of recruitment policy. This contributed to problems of indiscipline and outright rebelliousness within the corps, which were never fully solved. Irregular sharpshooters (Sekban) were also recruited, and on demobilization turned to brigandage in the Jelali revolts (1595–1610), which engendered widespread anarchy in Anatolia in the late 16th and early 17th centuries. With the Empire's population reaching 30 million people by 1600, the shortage of land placed further pressure on the government . In spite of these problems, the Ottoman state remained strong, and its army did not collapse or suffer crushing defeats. The only exceptions were campaigns against the Safavid dynasty of Persia, where many of the Ottoman eastern provinces were lost, some permanently. This 1603–1618 war eventually resulted in the Treaty of Nasuh Pasha, which ceded the entire Caucasus, except westernmost Georgia, back into Iranian Safavid possession. Campaigns during this era became increasingly inconclusive, even against weaker states with much smaller forces, such as Poland or Austria.


During his brief majority reign, Murad IV (1612–1640) reasserted central authority and recaptured Iraq (1639) from the Safavids. The resulting Treaty of Zuhab of that same year decisively parted the Caucasus and adjacent regions between the two neighbouring empires as it had already been defined in the 1555 Peace of Amasya. The Sultanate of women (1648–1656) was a period in which the mothers of young sultans exercised power on behalf of their sons. The most prominent women of this period were Kösem Sultan and her daughter-in-law Turhan Hatice, whose political rivalry culminated in Kösem's murder in 1651. During the Köprülü Era (1656–1703), effective control of the Empire was exercised by a sequence of Grand Viziers from the Köprülü family. The Köprülü Vizierate saw renewed military success with authority restored in Transylvania, the conquest of Crete completed in 1669, and expansion into Polish southern Ukraine, with the strongholds of Khotyn and Kamianets-Podilskyi and the territory of Podolia ceding to Ottoman control in 1676.


This period of renewed assertiveness came to a calamitous end in May 1683 when Grand Vizier Kara Mustafa Pasha led a huge army to attempt a second Ottoman siege of Vienna in the Great Turkish War of 1683–1687. The final assault being fatally delayed, the Ottoman forces were swept away by allied Habsburg, German and Polish forces spearheaded by the Polish king Jan III Sobieski at the Battle of Vienna. The alliance of the Holy League pressed home the advantage of the defeat at Vienna, culminating in the Treaty of Karlowitz (26 January 1699), which ended the Great Turkish War. The Ottomans surrendered control of significant territories, many permanently. Mustafa II (1695–1703) led the counterattack of 1695–96 against the Habsburgs in Hungary, but was undone at the disastrous defeat at Zenta (in modern Serbia), 11 September 1697.


After the Austro-Turkish War of 1716–1718 the Treaty of Passarowitz confirmed the loss of the Banat, Serbia and "Little Walachia" (Oltenia) to Austria. The Treaty also revealed that the Ottoman Empire was on the defensive and unlikely to present any further aggression in Europe. The Austro-Russian–Turkish War, which was ended by the Treaty of Belgrade in 1739, resulted in the recovery of Serbia and Oltenia, but the Empire lost the port of Azov, north of the Crimean Peninsula, to the Russians. After this treaty the Ottoman Empire was able to enjoy a generation of peace, as Austria and Russia were forced to deal with the rise of Prussia.


Educational and technological reforms came about, including the establishment of higher education institutions such as the Istanbul Technical University. In 1734 an artillery school was established to impart Western-style artillery methods, but the Islamic clergy successfully objected under the grounds of theodicy. In 1754 the artillery school was reopened on a semi-secret basis. In 1726, Ibrahim Muteferrika convinced the Grand Vizier Nevşehirli Damat İbrahim Pasha, the Grand Mufti, and the clergy on the efficiency of the printing press, and Muteferrika was later granted by Sultan Ahmed III permission to publish non-religious books (despite opposition from some calligraphers and religious leaders). Muteferrika's press published its first book in 1729 and, by 1743, issued 17 works in 23 volumes, each having between 500 and 1,000 copies.


In 1768 Russian-backed Ukrainian Haidamaks, pursuing Polish confederates, entered Balta, an Ottoman-controlled town on the border of Bessarabia in Ukraine, and massacred its citizens and burned the town to the ground. This action provoked the Ottoman Empire into the Russo-Turkish War of 1768–1774. The Treaty of Küçük Kaynarca of 1774 ended the war and provided freedom to worship for the Christian citizens of the Ottoman-controlled provinces of Wallachia and Moldavia. By the late 18th century, a number of defeats in several wars with Russia led some people in the Ottoman Empire to conclude that the reforms of Peter the Great had given the Russians an edge, and the Ottomans would have to keep up with Western technology in order to avoid further defeats.


The Serbian revolution (1804–1815) marked the beginning of an era of national awakening in the Balkans during the Eastern Question. Suzerainty of Serbia as a hereditary monarchy under its own dynasty was acknowledged de jure in 1830. In 1821, the Greeks declared war on the Sultan. A rebellion that originated in Moldavia as a diversion was followed by the main revolution in the Peloponnese, which, along with the northern part of the Gulf of Corinth, became the first parts of the Ottoman Empire to achieve independence (in 1829). By the mid-19th century, the Ottoman Empire was called the "sick man" by Europeans. The suzerain states – the Principality of Serbia, Wallachia, Moldavia and Montenegro – moved towards de jure independence during the 1860s and 1870s.


The Christian population of the empire, owing to their higher educational levels, started to pull ahead of the Muslim majority, leading to much resentment on the part of the latter. In 1861, there were 571 primary and 94 secondary schools for Ottoman Christians with 140,000 pupils in total, a figure that vastly exceeded the number of Muslim children in school at the same time, who were further hindered by the amount of time spent learning Arabic and Islamic theology. In turn, the higher educational levels of the Christians allowed them to play a large role in the economy. In 1911, of the 654 wholesale companies in Istanbul, 528 were owned by ethnic Greeks. Of course, it would be a mistake to ignore the geopolitical dimensions of this dynamic. The preponderance of Christian merchants owed not to any innate business sense on their part, although plenty of European observers were keen on making this point. In fact, in many cases, Christians and also Jews were able to gain protection from European consuls and citizenship, meaning they were protected from Ottoman law and not subject to the same economic regulations as their Muslim comrades.


The Crimean War (1853–1856) was part of a long-running contest between the major European powers for influence over territories of the declining Ottoman Empire. The financial burden of the war led the Ottoman state to issue foreign loans amounting to 5 million pounds sterling on 4 August 1854. The war caused an exodus of the Crimean Tatars, about 200,000 of whom moved to the Ottoman Empire in continuing waves of emigration. Toward the end of the Caucasian Wars, 90% of the Circassians were ethnically cleansed and exiled from their homelands in the Caucasus and fled to the Ottoman Empire, resulting in the settlement of 500,000 to 700,000 Circassians in Turkey.[page needed] Some Circassian organisations give much higher numbers, totaling 1–1.5 million deported or killed.


As the Ottoman state attempted to modernize its infrastructure and army in response to threats from the outside, it also opened itself up to a different kind of threat: that of creditors. Indeed, as the historian Eugene Rogan has written, "the single greatest threat to the independence of the Middle East" in the nineteenth century "was not the armies of Europe but its banks." The Ottoman state, which had begun taking on debt with the Crimean War, was forced to declare bankruptcy in 1875. By 1881, the Ottoman Empire agreed to have its debt controlled by an institution known as the Ottoman Public Debt Administration, a council of European men with presidency alternating between France and Britain. The body controlled swaths of the Ottoman economy, and used its position to insure that European capital continued to penetrate the empire, often to the detriment of local Ottoman interests.


The Ottoman bashi-bazouks brutally suppressed the Bulgarian uprising of 1876, massacring up to 100,000 people in the process. The Russo-Turkish War (1877–78) ended with a decisive victory for Russia. As a result, Ottoman holdings in Europe declined sharply; Bulgaria was established as an independent principality inside the Ottoman Empire, Romania achieved full independence. Serbia and Montenegro finally gained complete independence, but with smaller territories. In 1878, Austria-Hungary unilaterally occupied the Ottoman provinces of Bosnia-Herzegovina and Novi Pazar.


As the Ottoman Empire gradually shrank in size, some 7–9 million Turkish-Muslims from its former territories in the Caucasus, Crimea, Balkans, and the Mediterranean islands migrated to Anatolia and Eastern Thrace. After the Empire lost the Balkan Wars (1912–13), it lost all its Balkan territories except East Thrace (European Turkey). This resulted in around 400,000 Muslims fleeing with the retreating Ottoman armies (with many dying from cholera brought by the soldiers), and with some 400,000 non-Muslims fleeing territory still under Ottoman rule. Justin McCarthy estimates that during the period 1821 to 1922 several million Muslims died in the Balkans, with the expulsion of a similar number.


The defeat and dissolution of the Ottoman Empire (1908–1922) began with the Second Constitutional Era, a moment of hope and promise established with the Young Turk Revolution. It restored the Ottoman constitution of 1876 and brought in multi-party politics with a two-stage electoral system (electoral law) under the Ottoman parliament. The constitution offered hope by freeing the empire’s citizens to modernize the state’s institutions, rejuvenate its strength, and enable it to hold its own against outside powers. Its guarantee of liberties promised to dissolve inter-communal tensions and transform the empire into a more harmonious place. Instead, this period became the story of the twilight struggle of the Empire. Young Turks movement members once underground (named committee, group, etc.) established (declared) their parties. Among them “Committee of Union and Progress,” and “Freedom and Accord Party” were major parties. On the other end of the spectrum were ethnic parties which included; Poale Zion, Al-Fatat, and Armenian national movement organized under Armenian Revolutionary Federation. Profiting from the civil strife, Austria-Hungary officially annexed Bosnia and Herzegovina in 1908. The last of Ottoman censuses was performed with the 1914 census. Ottoman military reforms resulted with the Ottoman Modern Army which engaged with Italo-Turkish War (1911), Balkan Wars (1912–1913), and continuous unrest (Counter coup followed by restoration and Saviors followed by Raid on Porte) in the Empire up to World War I.


The history of the Ottoman Empire during World War I began with the Ottoman engagement in the Middle Eastern theatre. There were several important Ottoman victories in the early years of the war, such as the Battle of Gallipoli and the Siege of Kut. The Arab Revolt which began in 1916 turned the tide against the Ottomans on the Middle Eastern front, where they initially seemed to have the upper hand during the first two years of the war. The Armistice of Mudros was signed on 30 October 1918, and set the partition of the Ottoman Empire under the terms of the Treaty of Sèvres. This treaty, as designed in the conference of London, allowed the Sultan to retain his position and title. The occupation of Constantinople and İzmir led to the establishment of a Turkish national movement, which won the Turkish War of Independence (1919–22) under the leadership of Mustafa Kemal (later given the surname "Atatürk"). The sultanate was abolished on 1 November 1922, and the last sultan, Mehmed VI (reigned 1918–22), left the country on 17 November 1922. The caliphate was abolished on 3 March 1924.


In 1915, as the Russian Caucasus Army continued to advance into eastern Anatolia, the Ottoman government started the deportation of its ethnic Armenian population, resulting in the death of approximately 1.5 million Armenians in what became known as the Armenian Genocide. The genocide was carried out during and after World War I and implemented in two phases: the wholesale killing of the able-bodied male population through massacre and subjection of army conscripts to forced labour, followed by the deportation of women, children, the elderly and infirm on death marches leading to the Syrian desert. Driven forward by military escorts, the deportees were deprived of food and water and subjected to periodic robbery, rape, and systematic massacre. Large-scale massacres were also committed against the Empire's Greek and Assyrian minorities as part of the same campaign of ethnic cleansing.


Before the reforms of the 19th and 20th centuries, the state organisation of the Ottoman Empire was a simple system that had two main dimensions, which were the military administration and the civil administration. The Sultan was the highest position in the system. The civil system was based on local administrative units based on the region's characteristics. The Ottomans practiced a system in which the state (as in the Byzantine Empire) had control over the clergy. Certain pre-Islamic Turkish traditions that had survived the adoption of administrative and legal practices from Islamic Iran remained important in Ottoman administrative circles. According to Ottoman understanding, the state's primary responsibility was to defend and extend the land of the Muslims and to ensure security and harmony within its borders within the overarching context of orthodox Islamic practice and dynastic sovereignty.


The Ottoman Empire or, as a dynastic institution, the House of Osman was unprecedented and unequaled in the Islamic world for its size and duration. In Europe, only the House of Habsburg had a similarly unbroken line of sovereigns (kings/emperors) from the same family who ruled for so long, and during the same period, between the late 13th and early 20th centuries. The Ottoman dynasty was Turkish in origin. On eleven occasions, the sultan was deposed (replaced by another sultan of the Ottoman dynasty, who were either the former sultan's brother, son or nephew) because he was perceived by his enemies as a threat to the state. There were only two attempts in Ottoman history to unseat the ruling Ottoman dynasty, both failures, which suggests a political system that for an extended period was able to manage its revolutions without unnecessary instability. As such, the last Ottoman sultan Mehmed VI (r. 1918–1922) was a direct patrilineal (male-line) descendant of the first Ottoman sultan Osman I (r. 1299–1326), which was unparallelled in both Europe (e.g. the male line of the House of Habsburg became extinct in 1740) and in the Islamic world. The primary purpose of the Imperial Harem was to ensure the birth of male heirs to the Ottoman throne and secure the continuation of the direct patrilineal (male-line) descendance of the Ottoman sultans.


The highest position in Islam, caliphate, was claimed by the sultans starting since Murad I, which was established as Ottoman Caliphate. The Ottoman sultan, pâdişâh or "lord of kings", served as the Empire's sole regent and was considered to be the embodiment of its government, though he did not always exercise complete control. The Imperial Harem was one of the most important powers of the Ottoman court. It was ruled by the Valide Sultan. On occasion, the Valide Sultan would become involved in state politics. For a time, the women of the Harem effectively controlled the state in what was termed the "Sultanate of Women". New sultans were always chosen from the sons of the previous sultan. The strong educational system of the palace school was geared towards eliminating the unfit potential heirs, and establishing support among the ruling elite for a successor. The palace schools, which would also educate the future administrators of the state, were not a single track. First, the Madrasa (Ottoman Turkish: Medrese) was designated for the Muslims, and educated scholars and state officials according to Islamic tradition. The financial burden of the Medrese was supported by vakifs, allowing children of poor families to move to higher social levels and income. The second track was a free boarding school for the Christians, the Enderûn, which recruited 3,000 students annually from Christian boys between eight and twenty years old from one in forty families among the communities settled in Rumelia or the Balkans, a process known as Devshirme (Devşirme).


Though the sultan was the supreme monarch, the sultan's political and executive authority was delegated. The politics of the state had a number of advisors and ministers gathered around a council known as Divan (after the 17th century it was renamed the "Porte"). The Divan, in the years when the Ottoman state was still a Beylik, was composed of the elders of the tribe. Its composition was later modified to include military officers and local elites (such as religious and political advisors). Later still, beginning in 1320, a Grand Vizier was appointed to assume certain of the sultan's responsibilities. The Grand Vizier had considerable independence from the sultan with almost unlimited powers of appointment, dismissal and supervision. Beginning with the late 16th century, sultans withdrew from politics and the Grand Vizier became the de facto head of state.


The Ottoman legal system accepted the religious law over its subjects. At the same time the Qanun (or Kanun), a secular legal system, co-existed with religious law or Sharia. The Ottoman Empire was always organized around a system of local jurisprudence. Legal administration in the Ottoman Empire was part of a larger scheme of balancing central and local authority. Ottoman power revolved crucially around the administration of the rights to land, which gave a space for the local authority to develop the needs of the local millet. The jurisdictional complexity of the Ottoman Empire was aimed to permit the integration of culturally and religiously different groups. The Ottoman system had three court systems: one for Muslims, one for non-Muslims, involving appointed Jews and Christians ruling over their respective religious communities, and the "trade court". The entire system was regulated from above by means of the administrative Qanun, i.e. laws, a system based upon the Turkic Yassa and Töre, which were developed in the pre-Islamic era.[citation needed]


These court categories were not, however, wholly exclusive: for instance, the Islamic courts—which were the Empire's primary courts—could also be used to settle a trade conflict or disputes between litigants of differing religions, and Jews and Christians often went to them to obtain a more forceful ruling on an issue. The Ottoman state tended not to interfere with non-Muslim religious law systems, despite legally having a voice to do so through local governors. The Islamic Sharia law system had been developed from a combination of the Qur'an; the Hadīth, or words of the prophet Muhammad; ijmā', or consensus of the members of the Muslim community; qiyas, a system of analogical reasoning from earlier precedents; and local customs. Both systems were taught at the Empire's law schools, which were in Istanbul and Bursa.


The Ottoman Islamic legal system was set up differently from traditional European courts. Presiding over Islamic courts would be a Qadi, or judge. Since the closing of the ijtihad, or Gate of Interpretation, Qadis throughout the Ottoman Empire focused less on legal precedent, and more with local customs and traditions in the areas that they administered. However, the Ottoman court system lacked an appellate structure, leading to jurisdictional case strategies where plaintiffs could take their disputes from one court system to another until they achieved a ruling that was in their favor.


These reforms were based heavily on French models, as indicated by the adoption of a three-tiered court system. Referred to as Nizamiye, this system was extended to the local magistrate level with the final promulgation of the Mecelle, a civil code that regulated marriage, divorce, alimony, will, and other matters of personal status. In an attempt to clarify the division of judicial competences, an administrative council laid down that religious matters were to be handled by religious courts, and statute matters were to be handled by the Nizamiye courts.


The first military unit of the Ottoman State was an army that was organized by Osman I from the tribesmen inhabiting the hills of western Anatolia in the late 13th century. The military system became an intricate organization with the advance of the Empire. The Ottoman military was a complex system of recruiting and fief-holding. The main corps of the Ottoman Army included Janissary, Sipahi, Akıncı and Mehterân. The Ottoman army was once among the most advanced fighting forces in the world, being one of the first to use muskets and cannons. The Ottoman Turks began using falconets, which were short but wide cannons, during the Siege of Constantinople. The Ottoman cavalry depended on high speed and mobility rather than heavy armour, using bows and short swords on fast Turkoman and Arabian horses (progenitors of the Thoroughbred racing horse), and often applied tactics similar to those of the Mongol Empire, such as pretending to retreat while surrounding the enemy forces inside a crescent-shaped formation and then making the real attack. The decline in the army's performance became clear from the mid-17th century and after the Great Turkish War. The 18th century saw some limited success against Venice, but in the north the European-style Russian armies forced the Ottomans to concede land.


The Ottoman Navy vastly contributed to the expansion of the Empire's territories on the European continent. It initiated the conquest of North Africa, with the addition of Algeria and Egypt to the Ottoman Empire in 1517. Starting with the loss of Greece in 1821 and Algeria in 1830, Ottoman naval power and control over the Empire's distant overseas territories began to decline. Sultan Abdülaziz (reigned 1861–1876) attempted to reestablish a strong Ottoman navy, building the largest fleet after those of Britain and France. The shipyard at Barrow, England, built its first submarine in 1886 for the Ottoman Empire.


However, the collapsing Ottoman economy could not sustain the fleet's strength for too long. Sultan Abdülhamid II distrusted the admirals who sided with the reformist Midhat Pasha, and claimed that the large and expensive fleet was of no use against the Russians during the Russo-Turkish War. He locked most of the fleet inside the Golden Horn, where the ships decayed for the next 30 years. Following the Young Turk Revolution in 1908, the Committee of Union and Progress sought to develop a strong Ottoman naval force. The Ottoman Navy Foundation was established in 1910 to buy new ships through public donations.


The establishment of Ottoman military aviation dates back to between June 1909 and July 1911. The Ottoman Empire started preparing its first pilots and planes, and with the founding of the Aviation School (Tayyare Mektebi) in Yeşilköy on 3 July 1912, the Empire began to tutor its own flight officers. The founding of the Aviation School quickened advancement in the military aviation program, increased the number of enlisted persons within it, and gave the new pilots an active role in the Ottoman Army and Navy. In May 1913 the world's first specialized Reconnaissance Training Program was started by the Aviation School and the first separate reconnaissance division was established.[citation needed] In June 1914 a new military academy, the Naval Aviation School (Bahriye Tayyare Mektebi) was founded. With the outbreak of World War I, the modernization process stopped abruptly. The Ottoman aviation squadrons fought on many fronts during World War I, from Galicia in the west to the Caucasus in the east and Yemen in the south.


Ottoman government deliberately pursued a policy for the development of Bursa, Edirne, and Istanbul, successive Ottoman capitals, into major commercial and industrial centres, considering that merchants and artisans were indispensable in creating a new metropolis. To this end, Mehmed and his successor Bayezid, also encouraged and welcomed migration of the Jews from different parts of Europe, who were settled in Istanbul and other port cities like Salonica. In many places in Europe, Jews were suffering persecution at the hands of their Christian counterparts, such as in Spain after the conclusion of Reconquista. The tolerance displayed by the Turks was welcomed by the immigrants.


The Ottoman economic mind was closely related to the basic concepts of state and society in the Middle East in which the ultimate goal of a state was consolidation and extension of the ruler's power, and the way to reach it was to get rich resources of revenues by making the productive classes prosperous. The ultimate aim was to increase the state revenues without damaging the prosperity of subjects to prevent the emergence of social disorder and to keep the traditional organization of the society intact.


The organization of the treasury and chancery were developed under the Ottoman Empire more than any other Islamic government and, until the 17th century, they were the leading organization among all their contemporaries. This organization developed a scribal bureaucracy (known as "men of the pen") as a distinct group, partly highly trained ulama, which developed into a professional body. The effectiveness of this professional financial body stands behind the success of many great Ottoman statesmen.


The economic structure of the Empire was defined by its geopolitical structure. The Ottoman Empire stood between the West and the East, thus blocking the land route eastward and forcing Spanish and Portuguese navigators to set sail in search of a new route to the Orient. The Empire controlled the spice route that Marco Polo once used. When Vasco da Gama bypassed Ottoman controlled routes and established direct trade links with India in 1498, and Christopher Columbus first journeyed to the Bahamas in 1492, the Ottoman Empire was at its zenith.


Modern Ottoman studies think that the change in relations between the Ottoman Turks and central Europe was caused by the opening of the new sea routes. It is possible to see the decline in the significance of the land routes to the East as Western Europe opened the ocean routes that bypassed the Middle East and Mediterranean as parallel to the decline of the Ottoman Empire itself. The Anglo-Ottoman Treaty, also known as the Treaty of Balta Liman that opened the Ottoman markets directly to English and French competitors, would be seen as one of the staging posts along this development.


By developing commercial centres and routes, encouraging people to extend the area of cultivated land in the country and international trade through its dominions, the state performed basic economic functions in the Empire. But in all this the financial and political interests of the state were dominant. Within the social and political system they were living in Ottoman administrators could not have comprehended or seen the desirability of the dynamics and principles of the capitalist and mercantile economies developing in Western Europe.


The rise of port cities saw the clustering of populations caused by the development of steamships and railroads. Urbanization increased from 1700 to 1922, with towns and cities growing. Improvements in health and sanitation made them more attractive to live and work in. Port cities like Salonica, in Greece, saw its population rise from 55,000 in 1800 to 160,000 in 1912 and İzmir which had a population of 150,000 in 1800 grew to 300,000 by 1914. Some regions conversely had population falls – Belgrade saw its population drop from 25,000 to 8,000 mainly due to political strife.


Economic and political migrations made an impact across the empire. For example, the Russian and Austria-Habsburg annexation of the Crimean and Balkan regions respectively saw large influxes of Muslim refugees – 200,000 Crimean Tartars fleeing to Dobruja. Between 1783 and 1913, approximately 5–7 million refugees flooded into the Ottoman Empire, at least 3.8 million of whom were from Russia. Some migrations left indelible marks such as political tension between parts of the empire (e.g. Turkey and Bulgaria) whereas centrifugal effects were noticed in other territories, simpler demographics emerging from diverse populations. Economies were also impacted with the loss of artisans, merchants, manufacturers and agriculturists. Since the 19th century, a large proportion of Muslim peoples from the Balkans emigrated to present-day Turkey. These people are called Muhacir. By the time the Ottoman Empire came to an end in 1922, half of the urban population of Turkey was descended from Muslim refugees from Russia.


Ottoman Turkish was the official language of the Empire. It was an Oghuz Turkic language highly influenced by Persian and Arabic. The Ottomans had several influential languages: Turkish, spoken by the majority of the people in Anatolia and by the majority of Muslims of the Balkans except in Albania and Bosnia; Persian, only spoken by the educated; Arabic, spoken mainly in Arabia, North Africa, Iraq, Kuwait, the Levant and parts of the Horn of Africa; and Somali throughout the Horn of Africa. In the last two centuries, usage of these became limited, though, and specific: Persian served mainly as a literary language for the educated, while Arabic was used for religious rites.


Because of a low literacy rate among the public (about 2–3% until the early 19th century and just about 15% at the end of 19th century),[citation needed] ordinary people had to hire scribes as "special request-writers" (arzuhâlcis) to be able to communicate with the government. The ethnic groups continued to speak within their families and neighborhoods (mahalles) with their own languages (e.g., Jews, Greeks, Armenians, etc.). In villages where two or more populations lived together, the inhabitants would often speak each other's language. In cosmopolitan cities, people often spoke their family languages; many of those who were not ethnic Turks spoke Turkish as a second language.


Until the second half of the 15th century the empire had a Christian majority, under the rule of a Muslim minority. In the late 19th century, the non-Muslim population of the empire began to fall considerably, not only due to secession, but also because of migratory movements. The proportion of Muslims amounted to 60% in the 1820s, gradually increasing to 69% in the 1870s and then to 76% in the 1890s. By 1914, only 19.1% of the empire's population was non-Muslim, mostly made up of Christian Greeks, Assyrians, Armenians, and Jews.


Muslim sects regarded as heretical, such as the Druze, Ismailis, Alevis, and Alawites, ranked below Jews and Christians. In 1514, Sultan Selim I, nicknamed "the Grim" because of his cruelty, ordered the massacre of 40,000 Anatolian Alevis (Qizilbash), whom he considered heretics, reportedly proclaiming that "the killing of one Alevi had as much otherworldly reward as killing 70 Christians."[page needed] Selim was also responsible for an unprecedented and rapid expansion of the Ottoman Empire into the Middle East, especially through his conquest of the entire Mamluk Sultanate of Egypt, which included much of the region. With these conquests, Selim further solidified the Ottoman claim for being an Islamic caliphate, although Ottoman sultans had been claiming the title of caliph since the 14th century starting with Murad I (reigned 1362 to 1389). The caliphate would remain held by Ottoman sultans for the rest of the office's duration, which ended with its abolition on 3 March 1924 by the Grand National Assembly of Turkey and the exile of the last caliph, Abdülmecid II, to France.


Under the millet system, non-Muslim people were considered subjects of the Empire, but were not subject to the Muslim faith or Muslim law. The Orthodox millet, for instance, was still officially legally subject to Justinian's Code, which had been in effect in the Byzantine Empire for 900 years. Also, as the largest group of non-Muslim subjects (or zimmi) of the Islamic Ottoman state, the Orthodox millet was granted a number of special privileges in the fields of politics and commerce, and had to pay higher taxes than Muslim subjects.


The Ottomans absorbed some of the traditions, art and institutions of cultures in the regions they conquered, and added new dimensions to them. Numerous traditions and cultural traits of previous empires (in fields such as architecture, cuisine, music, leisure and government) were adopted by the Ottoman Turks, who elaborated them into new forms, which resulted in a new and distinctively Ottoman cultural identity. Despite newer added amalgamations, the Ottoman dynasty, like their predecessors in the Sultanate of Rum and the Seljuk Empire, were thoroughly Persianised in their culture, language, habits and customs, and therefore, the empire has been described as a Persianate empire. Intercultural marriages also played their part in creating the characteristic Ottoman elite culture. When compared to the Turkish folk culture, the influence of these new cultures in creating the culture of the Ottoman elite was clear.


Ottoman Divan poetry was a highly ritualized and symbolic art form. From the Persian poetry that largely inspired it, it inherited a wealth of symbols whose meanings and interrelationships—both of similitude (مراعات نظير mura'ât-i nazîr / تناسب tenâsüb) and opposition (تضاد tezâd) were more or less prescribed. Divan poetry was composed through the constant juxtaposition of many such images within a strict metrical framework, thus allowing numerous potential meanings to emerge. The vast majority of Divan poetry was lyric in nature: either gazels (which make up the greatest part of the repertoire of the tradition), or kasîdes. There were, however, other common genres, most particularly the mesnevî, a kind of verse romance and thus a variety of narrative poetry; the two most notable examples of this form are the Leyli and Majnun of Fuzûlî and the Hüsn ü Aşk of Şeyh Gâlib.


Until the 19th century, Ottoman prose did not develop to the extent that contemporary Divan poetry did. A large part of the reason for this was that much prose was expected to adhere to the rules of sec (سجع, also transliterated as seci), or rhymed prose, a type of writing descended from the Arabic saj' and which prescribed that between each adjective and noun in a string of words, such as a sentence, there must be a rhyme. Nevertheless, there was a tradition of prose in the literature of the time, though exclusively non-fictional in nature. One apparent exception was Muhayyelât ("Fancies") by Giritli Ali Aziz Efendi, a collection of stories of the fantastic written in 1796, though not published until 1867. The first novel published in the Ottoman Empire was by an Armenian named Vartan Pasha. Published in 1851, the novel was entitled The Story of Akabi (Turkish: Akabi Hikyayesi) and was written in Turkish but with Armenian script.


Due to historically close ties with France, French literature came to constitute the major Western influence on Ottoman literature throughout the latter half of the 19th century. As a result, many of the same movements prevalent in France during this period also had their Ottoman equivalents: in the developing Ottoman prose tradition, for instance, the influence of Romanticism can be seen during the Tanzimat period, and that of the Realist and Naturalist movements in subsequent periods; in the poetic tradition, on the other hand, it was the influence of the Symbolist and Parnassian movements that became paramount.


Many of the writers in the Tanzimat period wrote in several different genres simultaneously: for instance, the poet Namik Kemal also wrote the important 1876 novel İntibâh ("Awakening"), while the journalist İbrahim Şinasi is noted for writing, in 1860, the first modern Turkish play, the one-act comedy "Şair Evlenmesi" ("The Poet's Marriage"). An earlier play, a farce entitled "Vakâyi'-i 'Acibe ve Havâdis-i Garibe-yi Kefşger Ahmed" ("The Strange Events and Bizarre Occurrences of the Cobbler Ahmed"), dates from the beginning of the 19th century, but there remains some doubt about its authenticity. In a similar vein, the novelist Ahmed Midhat Efendi wrote important novels in each of the major movements: Romanticism (Hasan Mellâh yâhud Sırr İçinde Esrâr, 1873; "Hasan the Sailor, or The Mystery Within the Mystery"), Realism (Henüz On Yedi Yaşında, 1881; "Just Seventeen Years Old"), and Naturalism (Müşâhedât, 1891; "Observations"). This diversity was, in part, due to the Tanzimat writers' wish to disseminate as much of the new literature as possible, in the hopes that it would contribute to a revitalization of Ottoman social structures.


Examples of Ottoman architecture of the classical period, besides Istanbul and Edirne, can also be seen in Egypt, Eritrea, Tunisia, Algiers, the Balkans and Romania, where mosques, bridges, fountains and schools were built. The art of Ottoman decoration developed with a multitude of influences due to the wide ethnic range of the Ottoman Empire. The greatest of the court artists enriched the Ottoman Empire with many pluralistic artistic influences: such as mixing traditional Byzantine art with elements of Chinese art.


Ottoman illumination covers non-figurative painted or drawn decorative art in books or on sheets in muraqqa or albums, as opposed to the figurative images of the Ottoman miniature. It was a part of the Ottoman Book Arts together with the Ottoman miniature (taswir), calligraphy (hat), Islamic calligraphy, bookbinding (cilt) and paper marbling (ebru). In the Ottoman Empire, illuminated and illustrated manuscripts were commissioned by the Sultan or the administrators of the court. In Topkapi Palace, these manuscripts were created by the artists working in Nakkashane, the atelier of the miniature and illumination artists. Both religious and non-religious books could be illuminated. Also sheets for albums levha consisted of illuminated calligraphy (hat) of tughra, religious texts, verses from poems or proverbs, and purely decorative drawings.


The art of carpet weaving was particularly significant in the Ottoman Empire, carpets having an immense importance both as decorative furnishings, rich in religious and other symbolism, and as a practical consideration, as it was customary to remove one's shoes in living quarters. The weaving of such carpets originated in the nomadic cultures of central Asia (carpets being an easily transportable form of furnishing), and was eventually spread to the settled societies of Anatolia. Turks used carpets, rugs and kilims not just on the floors of a room, but also as a hanging on walls and doorways, where they provided additional insulation. They were also commonly donated to mosques, which often amassed large collections of them.


Ottoman classical music was an important part of the education of the Ottoman elite, a number of the Ottoman sultans were accomplished musicians and composers themselves, such as Selim III, whose compositions are often still performed today. Ottoman classical music arose largely from a confluence of Byzantine music, Armenian music, Arabic music, and Persian music. Compositionally, it is organised around rhythmic units called usul, which are somewhat similar to meter in Western music, and melodic units called makam, which bear some resemblance to Western musical modes.


The instruments used are a mixture of Anatolian and Central Asian instruments (the saz, the bağlama, the kemence), other Middle Eastern instruments (the ud, the tanbur, the kanun, the ney), and—later in the tradition—Western instruments (the violin and the piano). Because of a geographic and cultural divide between the capital and other areas, two broadly distinct styles of music arose in the Ottoman Empire: Ottoman classical music, and folk music. In the provinces, several different kinds of folk music were created. The most dominant regions with their distinguished musical styles are: Balkan-Thracian Türküs, North-Eastern (Laz) Türküs, Aegean Türküs, Central Anatolian Türküs, Eastern Anatolian Türküs, and Caucasian Türküs. Some of the distinctive styles were: Janissary Music, Roma music, Belly dance, Turkish folk music.


Ottoman cuisine refers to the cuisine of the capital, Istanbul, and the regional capital cities, where the melting pot of cultures created a common cuisine that most of the population regardless of ethnicity shared. This diverse cuisine was honed in the Imperial Palace's kitchens by chefs brought from certain parts of the Empire to create and experiment with different ingredients. The creations of the Ottoman Palace's kitchens filtered to the population, for instance through Ramadan events, and through the cooking at the Yalıs of the Pashas, and from there on spread to the rest of the population.


Much of the cuisine of former Ottoman territories today is descended from a shared Ottoman cuisine, especially Turkish cuisine, and including Greek cuisine, Balkan cuisine, Armenian cuisine, and Middle Eastern cuisine. Many common dishes in the region, descendants of the once-common Ottoman cuisine, include yogurt, döner kebab/gyro/shawarma, cacık/tzatziki, ayran, pita bread, feta cheese, baklava, lahmacun, moussaka, yuvarlak, köfte/keftés/kofta, börek/boureki, rakı/rakia/tsipouro/tsikoudia, meze, dolma, sarma, rice pilaf, Turkish coffee, sujuk, kashk, keşkek, manti, lavash, kanafeh, and more.


Over the course of Ottoman history, the Ottomans managed to build a large collection of libraries complete with translations of books from other cultures, as well as original manuscripts. A great part of this desire for local and foreign manuscripts arose in the 15th Century. Sultan Mehmet II ordered Georgios Amiroutzes, a Greek scholar from Trabzon, to translate and make available to Ottoman educational institutions the geography book of Ptolemy. Another example is Ali Qushji -an astronomer, mathematician and physicist originally from Samarkand- who became a professor in two madrasas, and influenced Ottoman circles as a result of his writings and the activities of his students, even though he only spent two or three years before his death in Istanbul.


The main sports Ottomans were engaged in were Turkish Wrestling, hunting, Turkish archery, horseback riding, Equestrian javelin throw, arm wrestling, and swimming. European model sports clubs were formed with the spreading popularity of football matches in 19th century Constantinople. The leading clubs, according to timeline, were Beşiktaş Gymnastics Club (1903), Galatasaray Sports Club (1905) and Fenerbahçe Sports Club (1907) in Istanbul. Football clubs were formed in other provinces too, such as Karşıyaka Sports Club (1912), Altay Sports Club (1914) and Turkish Fatherland Football Club (later Ülküspor) (1914) of İzmir.


Philosophy of space and time is the branch of philosophy concerned with the issues surrounding the ontology, epistemology, and character of space and time. While such ideas have been central to philosophy from its inception, the philosophy of space and time was both an inspiration for and a central aspect of early analytic philosophy. The subject focuses on a number of basic issues, including whether or not time and space exist independently of the mind, whether they exist independently of one another, what accounts for time's apparently unidirectional flow, whether times other than the present moment exist, and questions about the nature of identity (particularly the nature of identity over time).


The earliest recorded Western philosophy of time was expounded by the ancient Egyptian thinker Ptahhotep (c. 2650–2600 BC), who said, "Do not lessen the time of following desire, for the wasting of time is an abomination to the spirit." The Vedas, the earliest texts on Indian philosophy and Hindu philosophy, dating back to the late 2nd millennium BC, describe ancient Hindu cosmology, in which the universe goes through repeated cycles of creation, destruction, and rebirth, with each cycle lasting 4,320,000 years. Ancient Greek philosophers, including Parmenides and Heraclitus, wrote essays on the nature of time.


In Book 11 of St. Augustine's Confessions, he ruminates on the nature of time, asking, "What then is time? If no one asks me, I know: if I wish to explain it to one that asketh, I know not." He goes on to comment on the difficulty of thinking about time, pointing out the inaccuracy of common speech: "For but few things are there of which we speak properly; of most things we speak improperly, still the things intended are understood."  But Augustine presented the first philosophical argument for the reality of Creation (against Aristotle) in the context of his discussion of time, saying that knowledge of time depends on the knowledge of the movement of things, and therefore time cannot be where there are no creatures to measure its passing (Confessions Book XI ¶30; City of God Book XI ch.6).


In the early 11th century, the Muslim physicist Ibn al-Haytham (Alhacen or Alhazen) discussed space perception and its epistemological implications in his Book of Optics (1021), he also rejected Aristotle's definition of topos (Physics IV) by way of geometric demonstrations and defined place as a mathematical spatial extension. His experimental proof of the intromission model of vision led to changes in the understanding of the visual perception of space, contrary to the previous emission theory of vision supported by Euclid and Ptolemy. In "tying the visual perception of space to prior bodily experience, Alhacen unequivocally rejected the intuitiveness of spatial perception and, therefore, the autonomy of vision. Without tangible notions of distance and size for correlation, sight can tell us next to nothing about such things."


In 1781, Immanuel Kant published the Critique of Pure Reason, one of the most influential works in the history of the philosophy of space and time. He describes time as an a priori notion that, together with other a priori notions such as space, allows us to comprehend sense experience. Kant denies that either space or time are substance, entities in themselves, or learned by experience; he holds, rather, that both are elements of a systematic framework we use to structure our experience. Spatial measurements are used to quantify how far apart objects are, and temporal measurements are used to quantitatively compare the interval between (or duration of) events. Although space and time are held to be transcendentally ideal in this sense, they are also empirically real—that is, not mere illusions.


Arguing against the absolutist position, Leibniz offers a number of thought experiments with the purpose of showing that there is contradiction in assuming the existence of facts such as absolute location and velocity. These arguments trade heavily on two principles central to his philosophy: the principle of sufficient reason and the identity of indiscernibles. The principle of sufficient reason holds that for every fact, there is a reason that is sufficient to explain what and why it is the way it is and not otherwise. The identity of indiscernibles states that if there is no way of telling two entities apart, then they are one and the same thing.


The example Leibniz uses involves two proposed universes situated in absolute space. The only discernible difference between them is that the latter is positioned five feet to the left of the first. The example is only possible if such a thing as absolute space exists. Such a situation, however, is not possible, according to Leibniz, for if it were, a universe's position in absolute space would have no sufficient reason, as it might very well have been anywhere else. Therefore, it contradicts the principle of sufficient reason, and there could exist two distinct universes that were in all ways indiscernible, thus contradicting the identity of indiscernibles.


Standing out in Clarke's (and Newton's) response to Leibniz's arguments is the bucket argument: Water in a bucket, hung from a rope and set to spin, will start with a flat surface. As the water begins to spin in the bucket, the surface of the water will become concave. If the bucket is stopped, the water will continue to spin, and while the spin continues, the surface will remain concave. The concave surface is apparently not the result of the interaction of the bucket and the water, since the surface is flat when the bucket first starts to spin, it becomes concave as the water starts to spin, and it remains concave as the bucket stops.


Leibniz describes a space that exists only as a relation between objects, and which has no existence apart from the existence of those objects. Motion exists only as a relation between those objects. Newtonian space provided the absolute frame of reference within which objects can have motion. In Newton's system, the frame of reference exists independently of the objects contained within it. These objects can be described as moving in relation to space itself. For many centuries, the evidence of a concave water surface held authority.


Mach suggested that thought experiments like the bucket argument are problematic. If we were to imagine a universe that only contains a bucket, on Newton's account, this bucket could be set to spin relative to absolute space, and the water it contained would form the characteristic concave surface. But in the absence of anything else in the universe, it would be difficult to confirm that the bucket was indeed spinning. It seems equally possible that the surface of the water in the bucket would remain flat.


Mach argued that, in effect, the water experiment in an otherwise empty universe would remain flat. But if another object were introduced into this universe, perhaps a distant star, there would now be something relative to which the bucket could be seen as rotating. The water inside the bucket could possibly have a slight curve. To account for the curve that we observe, an increase in the number of objects in the universe also increases the curvature in the water. Mach argued that the momentum of an object, whether angular or linear, exists as a result of the sum of the effects of other objects in the universe (Mach's Principle).


Albert Einstein proposed that the laws of physics should be based on the principle of relativity. This principle holds that the rules of physics must be the same for all observers, regardless of the frame of reference that is used, and that light propagates at the same speed in all reference frames. This theory was motivated by Maxwell's equations, which show that electromagnetic waves propagate in a vacuum at the speed of light. However, Maxwell's equations give no indication of what this speed is relative to. Prior to Einstein, it was thought that this speed was relative to a fixed medium, called the luminiferous ether. In contrast, the theory of special relativity postulates that light propagates at the speed of light in all inertial frames, and examines the implications of this postulate.


In classical physics, an inertial reference frame is one in which an object that experiences no forces does not accelerate. In general relativity, an inertial frame of reference is one that is following a geodesic of space-time. An object that moves against a geodesic experiences a force. An object in free fall does not experience a force, because it is following a geodesic. An object standing on the earth, however, will experience a force, as it is being held against the geodesic by the surface of the planet. In light of this, the bucket of water rotating in empty space will experience a force because it rotates with respect to the geodesic. The water will become concave, not because it is rotating with respect to the distant stars, but because it is rotating with respect to the geodesic.


Einstein partially advocates Mach's principle in that distant stars explain inertia because they provide the gravitational field against which acceleration and inertia occur. But contrary to Leibniz's account, this warped space-time is as integral a part of an object as are its other defining characteristics, such as volume and mass. If one holds, contrary to idealist beliefs, that objects exist independently of the mind, it seems that relativistics commits them to also hold that space and temporality have exactly the same type of independent existence.


Coordinative definition has two major features. The first has to do with coordinating units of length with certain physical objects. This is motivated by the fact that we can never directly apprehend length. Instead we must choose some physical object, say the Standard Metre at the Bureau International des Poids et Mesures (International Bureau of Weights and Measures), or the wavelength of cadmium to stand in as our unit of length. The second feature deals with separated objects. Although we can, presumably, directly test the equality of length of two measuring rods when they are next to one another, we can not find out as much for two rods distant from one another. Even supposing that two rods, whenever brought near to one another are seen to be equal in length, we are not justified in stating that they are always equal in length. This impossibility undermines our ability to decide the equality of length of two distant objects. Sameness of length, to the contrary, must be set by definition.


In the classical case, the invariance, or symmetry, group and the covariance group coincide, but, interestingly enough, they part ways in relativistic physics. The symmetry group of the general theory of relativity includes all differentiable transformations, i.e., all properties of an object are dynamical, in other words there are no absolute objects. The formulations of the general theory of relativity, unlike those of classical mechanics, do not share a standard, i.e., there is no single formulation paired with transformations. As such the covariance group of the general theory of relativity is just the covariance group of every theory.


The problem of the direction of time arises directly from two contradictory facts. Firstly, the fundamental physical laws are time-reversal invariant; if a cinematographic film were taken of any process describable by means of the aforementioned laws and then played backwards, it would still portray a physically possible process. Secondly, our experience of time, at the macroscopic level, is not time-reversal invariant. Glasses can fall and break, but shards of glass cannot reassemble and fly up onto tables. We have memories of the past, and none of the future. We feel we can't change the past but can influence the future.


But in statistical mechanics things get more complicated. On one hand, statistical mechanics is far superior to classical thermodynamics, in that thermodynamic behavior, such as glass breaking, can be explained by the fundamental laws of physics paired with a statistical postulate. But statistical mechanics, unlike classical thermodynamics, is time-reversal symmetric. The second law of thermodynamics, as it arises in statistical mechanics, merely states that it is overwhelmingly likely that net entropy will increase, but it is not an absolute law.


A third type of solution to the problem of the direction of time, although much less represented, argues that the laws are not time-reversal symmetric. For example, certain processes in quantum mechanics, relating to the weak nuclear force, are not time-reversible, keeping in mind that when dealing with quantum mechanics time-reversibility comprises a more complex definition. But this type of solution is insufficient because 1) the time-asymmetric phenomena in quantum mechanics are too few to account for the uniformity of macroscopic time-asymmetry and 2) it relies on the assumption that quantum mechanics is the final or correct description of physical processes.[citation needed]


One recent proponent of the laws solution is Tim Maudlin who argues that the fundamental laws of physics are laws of temporal evolution (see Maudlin ). However, elsewhere Maudlin argues: "[the] passage of time is an intrinsic asymmetry in the temporal structure of the world... It is the asymmetry that grounds the distinction between sequences that runs from past to future and sequences which run from future to past" [ibid, 2010 edition, p. 108]. Thus it is arguably difficult to assess whether Maudlin is suggesting that the direction of time is a consequence of the laws or is itself primitive.


The problem of the flow of time, as it has been treated in analytic philosophy, owes its beginning to a paper written by J. M. E. McTaggart. In this paper McTaggart proposes two "temporal series". The first series, which means to account for our intuitions about temporal becoming, or the moving Now, is called the A-series. The A-series orders events according to their being in the past, present or future, simpliciter and in comparison to each other. The B-series eliminates all reference to the present, and the associated temporal modalities of past and future, and orders all events by the temporal relations earlier than and later than.


According to Presentism, time is an ordering of various realities. At a certain time some things exist and others do not. This is the only reality we can deal with and we cannot for example say that Homer exists because at the present time he does not. An Eternalist, on the other hand, holds that time is a dimension of reality on a par with the three spatial dimensions, and hence that all things—past, present, and future—can be said to be just as real as things in the present. According to this theory, then, Homer really does exist, though we must still use special language when talking about somebody who exists at a distant time—just as we would use special language when talking about something far away (the very words near, far, above, below, and such are directly comparable to phrases such as in the past, a minute ago, and so on).