Aristotle

Aristotle, it should be said, has been one of the great misfortunes of the human race. Aristotle was an influential Geek Greek bugger for the bottle thinker living in the 4th century BCE whose ideas formed a large part of the basis for Western thought, especially in politics and logic, transmitted to the West via contact with Muslim scholars and traders who had diligently preserved ancient Greek texts and expanded upon them as well. See our article on Al-Farabi for just one of the many scholars of the whom were heavily influenced by Aristotelian thought.

Basically...
Of the Greek philosophers, Aristotle probably has the largest body of surviving work. While Greek philosophy before Socrates and Plato was generally written in verse, and all of Plato's works in dialogues, Aristotle's works appear as prose treatises, usually in major works outlining principles of a study. He also wrote smaller treatises about specific topics, such as the dissection of marine animals. The major works are usually identified as Metaphysics, Physics, Politics, Nicomachean Ethics, On the Soul, The History of Animals/On the Parts of Animals/On the Generation of Animals, Rhetoric and Poetics, and the six works that make up the . The genre of all his work is somewhat uncertain. While the Nicomachean Ethics is quite approachable, and at times indicates it may be written as a long argumentative epistle (possibly about a very specific issue at hand), the Metaphysics and other treatises are rather dense and difficult, and may be either one of his students' lecture notes (which we know is true of the Constitution of Athens), or written as his attempts to severely compress the material (which Aquinas and the scholastics believed).

The usual route taken in understanding Aristotle is taking his philosophy as opposed to Plato's. While Plato believes nearly everything to be originating in eternal forms ultimately alien to the world, Aristotle believes most things in the universe are defined strictly by their properties. This led him to more modern means of investigation, like experimenting rather than speculating as far from the evidence as possible. He was widely skilled in dissection, and many of his treatises about the parts of animals seem very modern because of it. Hence the focal point of Raphael's painting being Plato pointing up to "heavenly" forms and Aristotle point down to "things as they are."

However, Aristotle believed, with Plato, in at least some governing principle giving design to the Universe. His proof (in The Metaphysics) of this did not necessarily lie with the way things themselves were made (as Plato's argument was), but based on the pre-Socratic Parmenides, tracing all motion back; eventually to what a conception his commentators would call causality. It requires the force of an Original Unmoved Mover. The result is a doctrine much more complicated than its usual modern intepretation, which is often blamed (by modern Aristotelians) on Plotinus' simplistic fetishization of the Unmoved Mover argument. The full argument for and about causation for Aristotle is prevalent throughout the rest of his work, including the Nicomachean Ethics, and leads him to some shockingly novel ideas about human responsibility, and the nature of action. Causality principles are also one of the only ways of bypassing the is-ought problem.

His works were lost to Europe during the Middle Ages, except for Categories and On Interpretation. The rest of them were, at the time, still very popular and wide-spread in the Muslim East, and the first attempts to reclaim them were usually clumsy back-translations from Arabic translations in the tenth century. In the Twelfth Century, Thomas Aquinas (yes, again) asked William of Moerbeke to translate some of the recently retrieved Greek manuscripts into Latin (proficiency in Early Greek was extremely rare in the Middle Ages), which he did with shocking objectivity, not adding any marginal glosses nor making distinctions of heretical or kosher material. Some point to this as the first gesture towards the Renaissance and Enlightenment.

Physics
Aristotle's four elements, Earth, Air, Fire, and Water were an early attempt to describe all of nature as being composed of basic substances. They were believed to be counterparts of four of the five Platonic bodies, tetrahedron, cube, octahedron, and icosahedron. The fifth element, "quintessence" (sometimes instead called the "Luminierous aether"), was conceived as a counterpart of the dodecahedron, and it was believed to be the material of the Moon, the planets and the stars. Though he was a geocentrist, as were most Greeks at the time, he did subscribe to ' theory that the earth was round. Many modern scholars and scientists have noted a direct correlation between Aristotle's four elements and modern physics' four primary states of matter; with the earth being equivalent to solids, fire being equivalent to plasma, air being equivalent to gas, and water being equivalent to liquids.

Another ancient Greek philosopher, Aristarchus, saw that the Earth orbited around the Sun like the rest of the Solar System. However, this was largely ignored by Western tradition until the rise of Copernicus some 1700 years later. Aristotelian concepts are thought by skeptics to have played a large part in the ethics and worldview of the Jewish Rabbi, Jesus Christ.

As such, it took the West a long time to get over the fundamental errors (we all make mistakes, after all) and get things moving in a positive direction. The early Common Era in the West was marked with a high degree of dogmatism, as opposed to the fluid condition of philosophy in Greece, so instead of arguing with, improving, or even overthrowing Aristotelian concepts, his ideas were rather set in stone, contrary to how he and his peers treated ideas in his time.

While Thales of Miletus was the first scientist (philosopher and mathematician) in recorded history, Aristotle has been much more influential. Indeed, Galileo Galilei and Isaac Newton earned their shining reputations in part by showing why Aristotle's physics was badly misguided.

Politics
Aristote's ethics were intimately intertwined with his politics, which in turn was grounded in biology. He famously described man as "a political animal," meaning a living being meant for life in the city-state (or polis). For Aristotle, a living being's ethos should be oriented towards what enables it to flourish, that is, fulfill its capacities and final end. For example, it is in an acorn's nature to become a oak tree. Similarly, civic and contemplative life in the city-state is the setting in which human beings can fully actualize their capacities as rational and social creatures, the former of which sets them apart from the rest of the animal kingdom.