First read: Aristotle's Metaphysics

18 Apr 2026

Table of Contents

Book I

Book 1 of Aristotle’s Metaphysics provides a survey of the history of philosophy, advancing the thesis that previous thinkers discovered the four causes, albeit somewhat obscurely.

What causes did the ancient philosophers recognize?

All of these principles are material, so, at a minimum, these thinkers recognized material causes.

Hesiod recognized that among existing things there must be a cause that moves things and brings them together. Hence, Hesiod recognized the efficient cause.

The Pythagoreans implicitly noticed the formal cause: they thought that number was the substance of all things. Things can change, but numbers would still be the underlying essence of objects. Unlike the proponents of material causes, the Pythagoreans were able to explain justice, the soul, reason, opportunity, and other things through modifications of numbers. They found that the modification of numbers gives form to things.

Empedocles noticed the final cause. He was the first to assert that, for example, friendship is the cause of good things, and thus to suggest that the good is a cause.

In arguing that previous thinkers did not fully grasp the four causes, Aristotle presents Empedocles as an example. Empedocles said that the essence and substance of a thing is its ratio, but he does not reconcile this claim with his other claim that the first principles are fire, earth, water, and air. He is grasping at the formal cause, but he does not articulate it clearly.

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