Teleology

Teleology is a reason or explanation for something in function of its end, purpose, or goal. For example, a teleological explanation of why forks have prongs is that this design helps humans eat certain foods; skewering food to allow humans to eat is what forks are for. It is derived from two Greek words: telos (end, goal, purpose) and logos (reason, explanation).

A purpose that is imposed by a human use, such as that of a fork, is called extrinsic. Natural teleology contends that natural entities have intrinsic purposes, irrespective of human use or opinion. For instance, Aristotle claimed that an acorn's intrinsic telos is to become a fully grown oak tree.

Though ancient atomists rejected the notion of natural teleology, teleological accounts of non-personal or non-human nature were explored and often endorsed in ancient and medieval philosophies, but fell into disfavor during the modern era (1600-1900).

In the late 18th century, Immanuel Kant used the concept of telos as a regulative principle in his Critique of Judgment. Teleology was also fundamental to the speculative philosophy of Georg Wilhelm Friedrich Hegel.