My favourite philosopher and man on the planet was a guy called Aristotle. Aristotle (Ancient Greek: Ἀριστοτέλης [aristotélɛːs], Aristotélēs) (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. Together with Plato and Socrates (Plato's teacher), Aristotle is one of the most important founding figures in Western philosophy. Aristotle's writings were the first to create a comprehensive system of Western philosophy, encompassing ethics, aesthetics, logic, science, politics, and metaphysics.
The Four Causes According to Aristotle:
1. Material cause describes the material out of which something is composed.
2. The formal cause is its form, i.e., the arrangement of that matter. It tells us what a thing is, that anything is determined by the definition, form, pattern, essence, whole, synthesis or archetype. It embraces the account of causes in terms of fundamental principles or general laws, as the whole is the cause of its parts, a relationship known as the whole-part causation.
3. The efficient cause is "the primary source", or that from which the change or the ending of the change first starts. It identifies 'what makes of what is made and what causes change of what is changed' and so suggests all sorts of agents, nonliving or living, acting as the sources of change or movement or rest.
4. The final cause is its purpose, or that for the sake of which a thing exists or is done, including both purposeful and instrumental actions and activities. The final cause or telos is the purpose or end that something is supposed to serve, or it is that from which and that to which the change is.
source:http://en.wikipedia.org/wiki/Aristotle