Aristotle (384 BC – 322 BC) was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology.
Aristotle was, uncommonly for an indisputable genius, a fine and generous man, who despite his prodigious intellect evinced a natural humility and generous devotion to his friends. Although it is true that he could be critical of his teacher where he differed with him, Aristotle regarded Plato warmly and with deep and grateful affection.
Aristotle regularly faults his predecessors, and he does so in a patterned and predictable way: he commonly contends that their explanations are at best only partially correct, first because they rest upon false assumptions but also because the earliest philosophers had not reflected sufficiently upon the character of explanation itself.
Aristotle spent much of his time writing lectures for his students. He wanted to explain his own ideas and the knowledge he had gained over his lifetime of study. These lectures were never really finished. He revised them again and again as he listened to the questions his students asked and what they discussed.
When Aristotle was 17 years old, his guardian sent him to the Academy of Plato in Athens to continue his studies. Plato was the most famous Greek philosopher of that time. At the Academy, Aristotle could spend his days deep in thought. He could engage in conversations with his fellow students about the nature of life and the big questions of his day.
In 335 BC Aristotle founded his own school the Lyceum in Athens. He arrived in the city with assistants to staff the school and a large range of teaching materials he had gathered while in Macedonia; books, maps, and other teaching material which may well have been intended at one stage to support Aristotle in his bid to become head of the Academy. The Academy had always been narrow in its interests but the Lyceum under Aristotle pursued a broader range of subjects.
Clearly Aristotle had a thorough grasp of elementary mathematics and believed mathematics to have great importance as one of three theoretical sciences. However, it is fair to say that he did not agree with Plato, who elevated mathematics to such a prominent place of study that there was little room for the range of sciences studied by Aristotle. The other two theoretical sciences, Aristotle claimed, were (using modern terminology) philosophy and theoretical physics.
Ancient Greek Philosophy, of which Aristotle was the high point, marked a fundamental turning point in the evolution of humanity and our ideas about our existence in the universe. Over the past 2,500 years Aristotle's philosophy has directly contributed to the evolution of our current science / reason based society. Thus it is unfortunate that many people imagine our post-modern society to now be so 'enlightened' that Aristotle (and other Ancient Greek Philosophers) have become irrelevant. In fact the opposite is true.
Aristotle considered the most fundamental features of reality in the twelve books of the Metafusikh (Metaphysics). Although experience of what happens is a key to all demonstrative knowledge, Aristotle supposed that the abstract study of "being qua being" must delve more deeply, in order to understand why things happen the way they do. A quick review of past attempts at achieving this goal reveals that earlier philosophers had created more difficult questions than they had answered: the Milesians over-emphasized material causes; Anaxagoras over-emphasized mind; and Plato got bogged down in the theory of forms. Aristotle intended to do better.
In the central books of the Metaphysics, Aristotle tried to develop an adequate analysis of subject-predicate judgments. Since logic and language rely heavily upon the copulative use of "is," careful study of these uses should reveal the genuine relationship that holds between substances and their features. Of course, Plato had already offered an extended account of this relationship, emphasizing the reality of the abstract forms rather than their material substratum.
Aristotle bases science upon the search for causes and the study of form and matter. As a reaction to Plato's Forms, he says that form is not and intangible concept in some unknown metaverse, but that it is the summation of an object's causes. Every object has four causes: material cause (what is it made up of?), efficient cause (what created it?), formal cause (what is it right now?), and final cause (what is it supposed to do?).