An idea · Classical Greek · first attested 340 BCE
The Four Causes
What it's made of, what it is, what made it, what it's for.
Aristotle's framework for explanation. To fully account for anything, one must specify its material cause (what it is made of), formal cause (what shape or essence it has), efficient cause (what brought it about), and final cause (what end it serves). Modern science largely abandoned the final cause – it threw the question "what for?" out of nature altogether; Aristotelians have been arguing ever since that too much went out with it.