At the core of biology and other sciences lies a problem-solving approach called the scientific method. 1  Make an observation. 2  Ask a question. 3  Form a hypothesis, or testable explanation. 4  Make a prediction based on the hypothesis.  Test the prediction.
Xi. Xi is the 14th letter of the Greek alphabet. It is pronounced in Modern Greek, and generally or in English. In the system of Greek numerals, it has a value of 60. Xi was derived from the Phoenician letter samekh. Xi is not to be confused with the letter chi, which gave its form to the Latin letter X.
The sum of li is the Taiji. This idea resembles the Buddhist notion of li, which also means principle. Zhu Xi maintained, however, that his notion is found in I Ching (Book of Changes), a classic source of Chinese philosophy. Zhu Xi's school came to be known as the School of Li, which is comparable to rationalism.