Aristotle says that the objects of experience are made up of matter which has taken up a form. This can be understood in a fairly unremarkable sense: in a statue of Aphrodite, the matter is marble, and the form is the shape of the goddess. However, there is also a metaphysical understanding. Prime matter is a mysterious sort of something that has no properties. Form is layered over this something to produce a substance. Aristotle says that prime matter cannot exist on its own, but only with a form layered over it.

It strikes me that to Aristotle, a form is almost like a concept. It is a comprehensible, perceptible structure overlayed on prime matter, and it is the form that enters into thought and reasoning, not the prime matter.

This seems similar to Kant's distinction between noumena and phenomena, where prime matter is the noumena and the form is the phenomenon. According to Kant, the phenomenon arises out of the nature of human cognition. Like the form, it is the aspect of an object that can enter into thought and reasoning. The noumena, being inaccessible to our minds, is for practical purposes equivalent to prime matter.

I was just wondering if anyone has explored this similarity. I haven't been able to find mention of it.

  • 1
    "Form is emptiness, emptiness is form." - The Heart Sutra
    – Scott Rowe
    Commented Jul 22, 2023 at 22:38
  • I find the Question very interesting, yet it languishes. People are not seeing the relationship to the Two Real Things. Or maybe I am imagining it...
    – Scott Rowe
    Commented Jul 25, 2023 at 1:06

1 Answer 1


It's a thoughtful observation to draw parallels between Aristotle's matter and form and Kant's noumena and phenomena. However, while there are superficial similarities, the concepts are different in some key aspects.

Aristotle's Matter and Form

In Aristotle's metaphysics, matter and form belong together in the composite reality of substances. Matter (hyle) is the potential aspect, the stuff or material out of which things are made, and form (morphe or eidos) is the actuality, the characteristic organization or pattern that makes a thing what it is. Importantly, form is not just a superficial shape, but the intrinsic organizing principle that gives a thing its nature or essence. For Aristotle, both matter and form are real and have ontological status.

Kant's Noumena and Phenomena

Kant, on the other hand, makes a clear epistemological distinction between noumena and phenomena. Phenomena are the appearances of things, the way things appear to us through our senses and cognitive faculties. Noumena, in contrast, are things as they are in themselves, independent of our perception or cognition. Kant argues that we can never truly know noumena; our knowledge is always of phenomena. For Kant, noumena do not have the same kind of reality as phenomena, because for him reality is largely a matter of what can be experienced.


While both distinctions involve a kind of duality, they operate on different levels. Aristotle's matter and form distinction is ontological and pertains to the very nature of physical entities in the world. Kant's noumena and phenomena distinction is epistemological and concerns the limits of human knowledge and perception.

Furthermore, Aristotle's matter and form are always intimately connected in actual substances, but Kant's noumena and phenomena are more radically separated, since noumena are entirely inaccessible to human knowledge.

That said, these are broad strokes, and there's certainly room for more nuanced discussions and interpretations. Some philosophers may indeed find productive ways to connect or compare these concepts. However, the distinction you're making isn't commonly drawn, likely because of the fundamental differences in Aristotle's and Kant's philosophical systems.

  • 1
    Different blind men, same elephant?
    – Scott Rowe
    Commented Jul 23, 2023 at 12:40

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