[1.3.5] Aristotle on Hylomorphism

“Central to Aristotle’s (384-322 BC) four-causal account of explanatory adequacy are the notions of matter (hulê) and form (eidos or morphê). Together, they constitute one of his most fundamental philosophical commitments, to hylomorphism:

Hylomorphism =df ordinary objects are composites of matter and form.
Aristotle’s hylomorphism was formulated originally to handle various puzzles about change…”

The following OntoUML diagram shows the main classes in the hylomorphic model:

Aristotle on hylomorphism
Object“‘ordinary objects’ … as a first approximation, it serves to rely on the sorts of examples Aristotle himself employs when motivating hylomorphism: statues and houses, horses and humans.”
Formform [in Aristotelian sense] =df that which makes some matter which is potentially F actually F
Acts, forms FormedMatter.
characterizes Object; acts on FormedMatter
Matter“matter [in Aristotelian sense] =df that which persists and which is, for some range of Fs, potentially F”
FormedMatterFormed matter is contained in an Object (not used by Aristotle).is phase of Matter; contained in Object
PrimeMatterPrime matter is usually described as pure potentiality, unformed. is subkind of Matter
PotentialityPotentiality is “possibility” that a thing can have.relates Matter with Object
ActualityActuality is change what realizes fulfillment of a possibility. relates Form with Object

“In general, argues Aristotle, in whatever category a change occurs, something is lost and something gained within that category, even while something else, a substance, remains in existence, as the subject of that change. Of course, substances can come into or go out of existence, in cases of generation or destruction; and these are changes in the category of substance. Evidently even in cases of change in this category, however, something persists. To take an example favourable to Aristotle, in the case of the generation of a statue, the bronze persists, but it comes to acquire a new form, a substantial rather than accidental form. In all cases, whether substantial or accidental, the two-factor analysis obtains: something remains the same and something is gained or lost.
In its most rudimentary formulation, hylomorphism simply labels each of the two factors: what remains is matter and what is gained is form

Importantly, matter and form come to be paired with another fundamental distinction, that between potentiality and actuality. Again in the case of the generation of a statue, we may say that the bronze is potentially a statue, but that it is an actual statue when and only when it is informed with the form of a statue. Of course, before being made into a statue, the bronze was also in potentiality a fair number of other artefacts—a cannon, a steam-engine, or a goal on a football pitch. Still, it was not in potentiality butter or a beach ball. This shows that potentiality is not the same as possibility: to say that x is potentially F is to say that x already has actual features in virtue of which it might be made to be F by the imposition of a F form upon it. So, given these various connections, it becomes possible to define form and matter generically a


  • Since the Aristotelian Form is a part of the Object, when the Object is destroyed, the Form is destroyed. Hence we have a ComponentOf OntoUML (similar to Composition in UML) relation between Object and Form.
  • Object is a Primary Substance in Aristotle’s four-fold categorization system [1.3.1]
  • The same hylomorphic structure can be observed in the previous post [1.3.4] about Causality, Potentiality, Actuality, Teleology:


  • The source of all citations: Shields, Christopher, “Aristotle“, The Stanford Encyclopedia of Philosophy (Winter 2016 Edition), Edward N. Zalta (ed.)
  • Ainsworth, Thomas, “Form vs. Matter“, The Stanford Encyclopedia of Philosophy (Spring 2016 Edition), Edward N. Zalta (ed.)

First published: 4/4/2019
Updated: 9/4/2019: Added Potentiality, Actuality
Updated: 6/9/2019: Added PrimeMatter
Updated: 9/2/2021: Added Form, FormedMatter
Updated: 7/12/2021

28 thoughts on “[1.3.5] Aristotle on Hylomorphism

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