What determines something to be a SUBSTANCE ?

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St Thomas, by Fra Bartolommeo, Florence

The Conception of Substance

In expounding this conception, we must always discriminate between (1) an item existing in extramental Reality, and (2) the (linguistic) term signifying that item.
Substance (i.e. for something to be a substance) shows at least four important aspects conferring to it its substantial nature (as such they constitute criteria for being-a-substance) :
  1. EXISTING BY, IN, AND ON ITSELF, i.e. NOT be something OF something (else), NOT be something IN something (else), NOT be something on (to) something (else), NOT existing by virtue of something else. All this WITHOUT any dependence on the possible specific meanings of the terms that signify the relevant items (beings, things) in (extramental) Reality (To exist either by itself or by virtue of something else physically, surely IS dependent on the specific meaning of the term signifying that item in reality : The leopard is dependent on the antilope, but the lizzard isn't (so dependent)). Accordingly it concerns an ontologically existing in and on itself, or in other words : ontological independence.
  2. TO EXIST AS ONE WHOLE, i.e. NOT be several (= more than one) things, NOT existing as an aggregate (of many things). It must be ONE, even if it has parts. It is a Totality (of [possible] parts).
  4. TO BE AN INDIVIDUAL, i.e. itself undivided, but divided (separated) from others, also from others of the same species. This implies that a species could be multiplied over (separate) individual cases.
Some of these aspects imply each other wholly or partly.
1. and 2. do not coincide, because something could certainly be ontologically independent, but nonetheless not be a unity, like a rock of Granite. Such a rock is an aggregate of three kinds of mineral crystals, jumbled together. So it is a multiplicity, albeit ontologically independent.
Moreover we must note that when something is ONE, it does not necessarily to be ontologically independent, for example REDNESS, and other accidental determinations.
The four aspects together bring with them the possibility of BEING-ITSELF (i.e. being a Self), and so this possibility could perhaps be seen as a main criterion for being a Substance. Lower wholes (lower Totalities) show a Self in a weakened way, for instance crystals. But it is not absent in those cases :   Crystals, during their growth, show for instance a speeded up healing of injuries. They 'repair' themselves by growing faster at the locality of injury. Because of this kind of phenomena crystals show some degree of individuality and identity, implying perhaps already a certain degree of having a Self (being-it-self) .
In the case of organisms having a Self is more pronounced :   They after all show a genuine active behavior toward self-preservation.
In the world of organisms, and also of inorganisms, we can expect to encounter a whole range of degrees of having a Self, making the investigation into the nature of (being a) Substance more complex, and making the concept of Substance less unambiguous.
Much stronger, and -- what we call -- consciously, this having of a Self is present in Man, in the form of his self-consciousness. In virtue of our self-consciousness we directly experience (1) (our) ontological independence, (2) having a self, (3) being ONE, and (4) (our) constancy during changes of our states : Socrates grows older and changes, but he remains Socrates. Some things concerning his body come and go, but he himself stays the same. By virtue of this direct experience the human example is an appropriate paradigm for expounding the (ontological) substance-accident structure, but it should not, without consideration, be generalized.
Being ontologically independent, being ONE, and possessing a Whatness of its own, together constitute being an Individual.
Let us examine these four aspects of being-a-substance more deeply :

Being-ontologically-Independent, versus Dependence : The Analogia Entis

As a (linguistic) term, a substance (now in the form of a subject) cannot be predicated (= cannot be said) of any other thing anymore, suggesting that a substance (as the thing signified by the subject-term) is ontologically independent. This suggestion includes also aggregates, like a piece of Granite.
A term signifying a genuine determination (property) or a state (= internal condition), can certainly be predicated of something else, suggesting that the extramental item for which it stands, its significatum, refers to something (else), of which it is a property or state, for instance the angles of a crystal (property), or, its outer form (state), which could be tablet-like or regular polyhedral [ The angles between corresponding faces of crystals that are compared with each other, are constant within the species, whereas the outer form is variable. But both necessarily point to a carrier, to receive and support them.]. So such an (extramental) item is not ontologically independent, it presupposes a substrate.
Of a substance we accordingly can say that it exists just like that. Of a property or state we cannot :   The property exists-on or -in (something else), and a state (like the tanning of Socrates) is-coincident-on (something else).
On such an ontological interpretation the doctrine of the " analogy of Being ", the analogia entis, is based. One can find this classical doctrine in St Thomas' Commentary on Aristotle's Metaphysics : In V Metaphysicorum, lectio 9, nr. 891 and 892 [See for this analogia entis the Essay on Substance and Accident ].
The relation between that (something) by virtue of which something is what it is, AND those items on and in it that are not so determining, St Thomas explains by means of the human paradigm in (among other locations in his works) In VII Metaphysicorum (abbreviated : In VII Met. ) lectio 5, nr. 1379. Here " humanity " means that by virtue of which something (for example Socrates) is a human. So here " humanity " signifies a principle. " Accidents " are properties or states, pertaining to something that itself is ontologically independent.
"Now to this extent humanity is not absolutely the same as man, because it implies only the essential principles of man and excludes all accidents. For humanity is that by which man is man. But none of the accidents of a man is that whereby he is a man. Hence all accidents of man are excluded from the meaning of humanity. Now it is the particular thing itself, namely, a man, which contains the essential principles and is that in which accidents can inhere. Hence although a man's accidents are not contained in his intelligible expression, still man does not signify something apart from his accidents. Therefore man signifies as a whole and humanity as a part."
Substance and Accident respectively embody a true, and non-true WAY OF BEING. This is the analogia entis with respect to substance and accident.
The correctness of such a conception depends among other things on the aswer to the question whether it perhaps is just an ontologization of our way of thinking, i.e. a confusion of Logic and Metaphysics (Nominalism says it is).
In order to validate the ontological status of the analogia entis we must at least appeal to an assessment of the constitution of things. But such an assessment (done by the investigator) could turn out to be necessarily preceded by a logical structure, which would mean that we are forced to use formal knowledge-structures and discriminations to speak about things at all. These logical structures must, it is true, have a foundation in extramental reality, a fundamentum in re [ I dismiss an idealistic view of knowledge, basing this dismissal on the fact that we, AND our rational structures, have historically (i.e. evolutionarily) developed in a reality context. See the Essay on the Realistic Theory of Knowledge .], but there need NOT necessarily be an isomorphic relation [See NOTE 1 .] between the logical structure of our thinking AND an ontological structure of the extramental things, i.e. between the syntax of thought (expressing itself by predicational structure and ways of signification) AND an ontological articulation.
So we must investigate whether the discrimination between substance and accident (but also for example between matter and form) is not just logical in nature, but indeed (also) ontological.
With respect to a per se predication St Thomas treats of this problem in his Commentary on Aristotle's Posterior Analytics : In I Post. An. lectio 10 [ The Posterior Analytics (Book I and Book II) of Aristotle is a kind of theory of science (an epistemology), especially concerning the deductive part of science, i.e. its non-empirical aspect. This theory of science is based on the Aristotelian ontology. ]. There St Thomas discriminates between the logical and the ontological. But with repect to the per accidens predication (in contrast with per se predication) he seems not to do so, for instance in De Ente et Essentia Chapter 6. In these texts (and also in In Met. VII, for example lectio 1, in Summa Theologica I-II, 53, 2, ad 3) St Thomas treats of the relation of an accident to the substance, and also the criteria for being a substance or being an accident. To be an accident is being in a subject, while such a subject is the substance s.str. But being a human is also in a subject, for example in Socrates. But in this case it should be a per se unity, an unum per se, while this is supposed not to be so in the case of a substance-accident composite. So we must investigate why this (ontological) composite should not be a per se unity, and (we must investigate) why first substance (f.e. Socrates) and second substance (f.e. man) should well be a per se unity. What is presupposed and/or stipulated here? As has been said, we must investigate whether perhaps these "ontological" relations are just logical relations, as Nominalism holds. A correct assessment of what it means to be an individual is crucial for deciding this question.
It is clear that Classical Metaphysics, was inspired by Logic and Language, but, as has been said earlier, perhaps partly justifiable. While in Antiquity and Middle Ages the philosophical task consisted in purifying Metaphysics from logical elements, of which the fundament-in-reality (fundamentum in re) is not necessarily isomorphic with these logical and linguistic structures, this task nowadays must be supplemented with the discussion and ontological evaluation of some relevant results from modern Natural Science. We did this in the first series of Essays.

The character of being a Totality and Unity, of a Substance

This Totality character is demanded by the Thomistic Metaphysics because of the assumption of there being only ONE Substantial Form in each substance. By virtue of this such a substance is ONE thing, it IS not its (physical) elements that are composing it. So the Totality character is a criterion for being a substance. But something is a Totality not until it again satisfies certain criteria. What are these criteria? When is something a Totality and not just an aggregate? Must it be a continuum, and is a material continuum possible at all? What is the status of the elements in such a Totality? Should we discriminate between being intrinsically a Totality (of elements), and being extrinsically a Totality, and will this discrimination always hold?

The possession of an Identity (Whatness) of its own

This brings us to the meanings of ESSENCE, WHATNESS and SUBSTANTIAL FORM.
Regarding Whatness, we can distinguish between a Whatness in a broader sense, Whatness s.l., and a Whatness in a narrower sense, Whatness s.str.
"Essence" indicates in the following ways an aspect of the way-of-being :
  1. When and if the Essence (of something) is given correctly and completely by means of (or by pointing to) a forma totius , i.e. (given) by that something that is designated by the term "forma totius" (= general, non-designated matter + substantial form), then the way-of-being is a material one, i.e. the term refers to the Essence of a sensible material thing, a thing that can be observed by the senses. "Forma totius" means :   the form of the whole, i.e. it comprises not only the form (i.e. the specific identity) of a thing, but also the material substrate (of that form) taken generally. It signifies the Essence as Whatness s.l of the thing. The form-only is called "forma partis", the form of the part. The form in this forma totius is the Substantial Form, and represents the Whatness s.str. of the thing.

  2. When and if the Essence (of something) is given correctly and completely by means of a form, then we have to do with an Essence of an immaterial thing, a 'separate being'. A form, so applied and pointed to, also indicates the Whatness of such an immaterial being, implying no difference anymore between Whatness s.str. and s.l.

  3. When and if we indicate the Essence with form, but now as an Essence incompletely indicated, then this form relates to the forma partis, i.e. the form-part of the forma totius, and then the Essence -- indicated in this way -- relates to the Whatness s.str. of a material thing, or, this form relates to -- but this time according to St Thomas -- a mathematical object, whereby the sensible matter which is in this case an extrinsic substrate -- associated with that form, is abstracted, but not the so-called intelligible matter. This intelligible matter is with regard to mathematical items :   (for example) the (mathematical) continuum. But according to St Thomas such mathematical forms belong to the Category of Quantity. So the form in this case is seen as accidental form, implying that indeed the sensible matter is extrinsic substrate. In both cases (of case 3.), the physical and the mathematical, the way-of-being of the Essence is the result of abstraction of matter, in contrast with that of the purely immaterial things (2).
Let us summarize (1), (2) and (3).
  1. The FORMA TOTIUS refers to the Essence as Whatness s.l. of sensible material things. General matter, i.e. matter as non-designated matter (non-delimited matter), is not abstracted. But that same matter, when considered as designated, is abstracted.

  2. The FORMA completely indicates the Essence and Whatness of wholly immaterial things ('separate beings'). The way of being of the Essence is not the result of abstraction of any matter.

  3. The FORMA PARTIS incompletely indicates the Essence, namely as Whatness s.str., of either a material sensible thing or a mathematical thing. In the case of material sensible things, signification of their Essence by the Forma partis means that matter as intrinsic substrate is abstracted. In the case of mathematical things, signification of their Essence by the Forma partis means that sensible matter as extrinsic substrate is abstracted, while intelligible matter as intrinsic substrate is not abstracted.
Concerning the Essence of sensible material things St Thomas writes the following in the beginning of Chapter 2 (Leonina edition) of De Ente et Essentia :

"In composed substances there are form and matter, for example, in man soul and body.
But we cannot say that either one of them alone may be said to be the essence. That matter alone is not the essence of a real thing is clear, since through its essence a real thing is knowable and assigned to a species or to a genus. But matter alone is neither a principle of knowledge, nor is it that by which something is assigned to a genus or to a species, rather a thing is so assigned by reason of its being something actual [ In Classical Metaphysics Matter -- as an ontological principle -- is considered not to be actual, but potential, it is potential with respect to the reception of one or another Form -- also an ontological principle. ].
Neither can the form alone of a composed substance be said to be its essence, although some try to assert this. For it is evident from what has been said that essence is what is signified by the definition of a real thing. And the definition of natural substances contains not only form, but matter as well, otherwise natural definitions and mathematical ones would not differ.
Neither can it be said that matter is placed in the definition of a natural substance as something added to its essence or as something outside its essence, because this mode of definition is proper to accidents, which do not have a perfect essence. This is why accidents must include in their definition a subject which is outside their genus. It is clear therefore that essence includes matter and form."
Thus Essence can be interpreted as Whatness-in-a-broader-sense, because the presence or absence of matter in this Essence (as a component of this Essence) indicates whether this thing is a material thing, or that it is a thing considered without (sensible) matter, implying it to be a mathematical 'thing', or that it is an immaterial substance.
Concerning the relation between the definition, signifying the Essence, and its parts, AND the thing defined, see St Thomas, In VII Met. lectio 9 and 10, and also De Ente et Essentia, and In An. Post. Book I.
For a holistic view of an organism, a view which recognizes only one Essence, one identity, being present in it, see, among other texts, In VII Met. lectio 10, nr. 1488 (In quoting we start with the last sentence of 1487) :
"It is clear, then, that in a sense the parts of the body are prior to "the concrete whole", i.e., to the composite, and in a sense they are not.
In fact they are prior in the way in which the simple is prior to the complex, inasmuch as the composite animal is constituted of them. However, they are not prior in the sense in which prior means something that can exist without something else, for the parts of the body cannot exist apart from the animal. Thus a finger is not a finger under all conditions, because one that is severed or dead is called such only equivocally, for example, the finger of a statue or that in a painting. But from this point of view parts of this kind are subsequent to the composite animal, because an animal can exist without a finger."
So a part of an organism does not have an identity of its own, because it cannot exist on its own, but only within the confines of a whole (having an identity of its own).

To be an Individual

This is an important aspect of -- and a criterion for -- to-be-a-Substance.
First of all we must distinguish to-be-an-individual from to-be-individual : the redness of a thing is individual, but it is not an individual. We shall call an individual (as opposed to just individual ) : AN INDIVIDUUM .
With respect to Man the interpretation of being-an-individual seems without problems. We can easily assess it more precisely.
But to-be-an-individual must be a generally valid criterion for to-be-a-substance, surely if we want to approach such matters within the Aristotelian Metaphysics (which is followed by St Thomas), and this demand also complies with Nominalism.
When, with regard to being-an-individual, we consider OTHER beings than just human beings, then we will see that it is in many cases not so clear what precisely is an individual. Is it in those (non-human) cases also always ONE, i.e. a unity? Does it, in those cases, also always have a 'historical' nature, i.e. extending itself over a certain time-span, or is it impossible to maintain such a view with respect to many such cases?
Moreover it turns out that the property of being-an-individual, taken with respect to all things, especially lower organisms and inorganic beings, manifests itself in several degrees. And when we look to Nominalism we see that it is forced to hold a peculiar view of being-an-individual.

Difference between "First Substance" and "Second Substance"

In the classical texts one distinguishes between First Substance and Second Substance.
And this also provides criteria for being-a-substance.
I will try to elucidate this difference along classical lines and some more recent insights.

First Substance

A First Substance relates to something particular : Socrates is a First Substance.
The emphasis lies on the individuum-aspect of the Species-Individuum Structure (SIS) characteristic of all (material) beings [See for this Structure the first section Matter and Form of the Essay on Substance and Accident].
A First Substance is subsistent, as opposed to the accidents.
The 10 Categories of Aristotle are about First Substance (also the first category is about First Substance) [For these Categories, see the same Essay here ].

Second Substance

(A) Second Substance is the first Category of Aristotle. It is an answer to the question what this first substance (pointed to with the finger) is : Socrates is a human being (We point to Socrates, a first substance, and ask what it is. The answer is : a human being).
Second substance forms, or emphasizes, the species-aspect of the Species-Individuum Structure (SIS).
Second Substance does not consider the particular, an so does not consider the aspect of strict individuality, it abstracts from the materia signata, which means it does not take into account the delimited matter, i.e. that aspect of matter that delineates the thing in space and time.
As a concept a Second Substance (for instance the concept HUMAN BEING) is only present in the Mind, as a sign for many extramental things (or things considered as if extramental). It then is the definiendum of a species, i.e. it is then that term that has to be defined (and a term is a mental item). It is (then) the definiendum of the term signifying a Second Substance, this term is the species. So the term HUMAN BEING is in this case a species, and the definition of this species could read : RATIONAL ANIMAL. That Second Substance which is signified by Second Substanse-as-a-term (a mental sign) is its significatum, and is the ontological Second Substance.
The ontological Second Substance places emphasis on the essential versus the accidental, in a First Substance.
It places less emphasis on subsistence (i.e. subsistence versus accidents).
It is the Essence of a First Substance.
The ontological Second Substance is NOT a universal [See for the UNIVERSAL here ].

Our quest concerns Substance as intrinsic Totality (a Totality of parts and determinations) :
First Substance, having an Essence (Second Substance).


We now have found a number of possible criteria for something to be a Substance.
Whether these criteria are generally valid must be investigated, and if they seem not to be generally valid, we must see how to adapt them.

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