Age of the Earth research. Most geological samples from Earth are unable to give a direct date of the formation of Earth from the solar nebula because Earth has undergone differentiation into the core, mantle, and crust, and this has then undergone a long history of mixing and unmixing of these sample reservoirs by plate tectonics, weathering and hydrothermal circulation. All of these processes may adversely affect isotopic dating mechanisms because the sample cannot always be assumed to have remained as a closed system, by which it is meant that either the parent or daughter nuclide (a species of atom characterised by the number
Civilization and Its Discontents Civilization and Its Discontents Civilization and Its Discontents is a book by Sigmund Freud, the founder of psychoanalysis. It was written in 1929 and first published in German in 1930 as "Das Unbehagen in der Kultur" ("The Uneasiness in Civilization"). Exploring what Freud sees as the important clash between the desire for individuality and the expectations of society, the book is considered one of Freud's most important and widely read works, and one of the most influential and studied books in the field of modern psychology. Freud enumerates what he sees as the fundamental tensions between civilization and the individual.