“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:

Class	Description	Relations
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.”
Form	“form [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”
FormedMatter	Formed matter is contained in an Object (not used by Aristotle).	is phase of Matter; contained in Object
PrimeMatter	Prime matter is usually described as pure potentiality, unformed.	is subkind of Matter
Potentiality	Potentiality is “possibility” that a thing can have.	relates Matter with Object
Actuality	Actuality 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

OBSERVATIONS:

• 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:

Sources

• 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

Aristotle (384-322 BC) in Physics II 3 and Metaphysics V 2, offers a general account of the method of the four causes. This knowledge-generating method applies to everything that requires an explanation by answering four questions regarding the matter, form, mean, and goal of an object.

• By answering, finding out the answers to the four questions, we define the four causes of the object: material, efficient, final, and formal causes.
• The four causes are essential elements of our knowledge regarding the analyzed object.
• The final cause has explanatory priority over the other three causes (teleology)
• The method of four causes includes the elements of the hylomorphism (see [1.3.5])

Aristotle’s model of knowledge of the four causes is presented in the following OntoUML diagram:

Class	Description	Relations
Object	A material object.	created with Mean; created for Goal
Potentiality	“A Potential State (dunamis) is the of an object capacity to be in a different and more completed state…” (Cohen, Mark, Reeve) e.g: a piece of bronze, casted into a statue or into a bowl. In Aristotle’s terminology, the piece of bronze has (at least) two different potentialities, since it is potentially a statue and also potentially a bowl.	relates Object with Matter
Actuality	“Actuality translates both energeia an entelecheia, and ‘actuality’ means just that area of overlap between being-at-work and being-at-an-end which expresses what it means to be something determinate. The words energeia and entelecheia have very different meanings, but function as synonyms because the world is such that things have identities, belong to species, act for ends, and form material into enduring organized wholes.” (Sachs)	relates Object with Form
Matter	The matter contained by the object.	sub-quantity of Object; is the MaterialCause
Mean	Mean by which the object was created	is the EfficientCause
Goal	Goal of the object	is the FinalCause
Form	Form of the object	is the FormalCause
MaterialCause	“The material cause: ‘that out of which’, e.g., the bronze of a statue. […] The bronze enters in the explanation of the production of the statue as the material cause. Note that the bronze is not only the material out of which the statue is made; it is also the subject of change, that is, the thing that undergoes the change and results in a statue. The bronze is melted and poured in order to acquire a new shape, the shape of the statue.” (Falcon)	subkind of Cause
EfficientCause	“The efficient cause: ‘the primary source of the change or rest’, e.g., the artisan, the art of bronze-casting the statue, the man who gives advice, the father of the child. […] However, an adequate explanation of the production of a statue requires also a reference to the efficient cause or the principle that produces the statue. For Aristotle, this principle is the art of bronze-casting the statue (Phys. 195 a 6–8. Cf. Metaph. 1013 b 6–9).” (Falcon)	subkind of Cause
FinalCause	The final cause: ‘the end, that for the sake of which a thing is done’, e.g., health is the end of walking, losing weight, purging, drugs, and surgical tools. […] A model is made for producing the statue. A mold is prepared for producing the statue. The bronze is melted and poured for producing the statue. Both the prior and the subsequent stage are for the sake of a certain end, the production of the statue. Clearly, the statue enters in the explanation of each step of the artistic production as the final cause or that for the sake of which everything in the production process is done. (Falcon)	subkind of Cause
FormalCause	“Formal cause, or the expression of what it is”, e.g., the shape of a statue. […] The bronze is melted and poured in order to acquire a new shape, the shape of the statue. This shape enters in the explanation of the production of the statue as the formal cause.” (Falcon)	subkind of Cause
Cause	“Aristotle places the following crucial condition on proper knowledge: we think we have knowledge of a thing only when we have grasped its cause (aitia).” (Falcon)	component of Knowledge (ofObject)
Knowledge (OfObject)	“Aristotle places the following crucial condition on proper knowledge [of object]: we think we have knowledge of a thing only when we have grasped its cause (aitia). That proper knowledge is knowledge of the cause is repeated in the Physics: we think we do not have knowledge of a thing until we have grasped its why, that is to say, its cause” (Falcon)

Sources

• Falcon, Andrea, “Aristotle on Causality“, The Stanford Encyclopedia of Philosophy (Spring 2019 Edition), Edward N. Zalta (ed.)
• Cohen, S. Marc and C. D. C. Reeve, “Aristotle’s Metaphysics“, The Stanford Encyclopedia of Philosophy (Winter 2020 Edition), Edward N. Zalta (ed.)
• Joe Sachs, “Aristotle: Motion and its Place in Nature”, Internet Encyclopedia of Philosophy
• Justin Humphreys, “Aristotle (384 B.C.E.—322 B.C.E.)“, Internet Encyclopedia of Philosophy
• Shields, Christopher, “Aristotle’s Psychology“, The Stanford Encyclopedia of Philosophy (Winter 2020 Edition), Edward N. Zalta (ed.)

First published: 28/03/2019
Updated: 09/04/2019: Added Mean and End
Updated: 21/04/2019: Added Knowledge
Updated: 21/12/2020
Updated: 7/12/2021