“It is clear from what has been said that there is a substance that is eternal and unmovable and separate from sensible things. It has been shown that this substance cannot have any magnitude, but is without parts and indivisible…But it has also been shown that it is impassive and unalterable; for all other changes are posterior to change and place.” – Aristotle, Metaphysics (1073a).1

We return now to our ongoing philosophical analysis of ultimate reality. We have seen how ultimate reality for the pre-Socratic Greeks came down to one existing intelligible world governed by logos and pervaded by energy, thought, and opposites, whereas Plato contributed the notion of God as the supremely Good, the reality of the output of the human mind, and his theory of the Forms as separately existing, ideal templates mirrored in the visible world. Today we move forward one generation to Plato’s student Aristotle, possibly the greatest single mind in history. An attempt to summarize Aristotle’s concept of ultimate reality in 1000 words or so is dubious at best and folly at worst, but so it must be for us to push forward in our journey.

We can think about ultimate reality for Aristotle from three overlapping perspectives: physics, metaphysics (first philosophy), and theology.


We should not expect here something akin to our modern science, but a partly empirical and partly deductive description. I will omit his patently erroneous theories (such as a free will of the heavenly bodies) which reflect the limitations of his time. An oversimplified understanding of Aristotle’s physics is that the universe consists of things or substances subject to two kinds of change.

Aristotle disassembles entities into substrate and form – for example, a chair is made of wood (substrate) arranged into a particular furniture piece (form), thus warranting the designation ‘substance.’ A substance can be the recipient of characteristics, but changing characteristics does not change the substance – consider the example of the chair where changing the color neither changes the wood nor the structure of the chair. Substances do not come into existence ex nihilo, rather their potential existence becomes actual – Aristotle’s first kind of change. Potential is actualized by virtue of four causes: (1) material, (2) formal, (3) efficient, and (4) final. Material and formal causes are the “what” (the wood and structure of the chair), efficient cause is the “how” (the worker’s building the chair) and final cause is the “why” (the chair as intended for sitting upon).

All substances have an internal finality best summarized: “The end of each object is to be itself.” Aristotle believes teleology or final cause applies not only to human creations but also to Nature which “makes nothing without a purpose”2 However, teleology does not apply to the universe overall which is eternal forward and backwards in time.

The second kind of change in the universe is motion which has three possible causes: Nature (e.g. the growth of a tree), force (e.g. gravity) or free will (e.g. human activities). Aristotle blends Heraclitus’ ‘change’ with Parmenides’ “constancy’ – thus, for example, when we throw a ball, it changes place or moves, but the ball itself is intact and remains a ball. A key point here is that a retrograde analysis of motion in the universe leads to a prime mover with free will.

(continued next post)


1Russell, Bertrand, A History of Western Philosophy. Simon & Schuster, New York, 1972. ISBN-13 978-1-4165-5477-6, page 168.

2Edwards, Paul (editor), The Encyclopedia of Philosophy. Macmillan Publishing Co., Inc. & The Free Press, 1972. Volume 1, page 158.

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