Entity and Ousia

[Boydstun]

Entity and Ousia

Contrasting Roark with many other people, Mallory remarks to Dominique of those others: “At the end there’s nothing left, nothing unreversed or unbetrayed; as if there had never been any entity, only a succession of adjectives fading in and out on an unformed mass” (GW V, 485).

Consider in Rand’s full metaphysics the finer structure in her conception of the law of identity: "Whatever you choose to consider, be it an object, an attribute, or an action, the law of identity remains the same. A leaf cannot be a stone at the same time, it cannot be all red and all green at the same time, it cannot freeze and burn at the same time. A is A (AS 1016).

Rand clearly intended here, in Galt’s Speech, that what is proposed for objects is to be generalized to entities. Every entity is of some kinds that are exclusive relative to other kinds of entity. Rand used the term entity in the paragraph preceding the object examples of leaf and stone. That is, she uses entity in the initial statement of her law of identity: “To exist is to be something, . . . it is to be an entity of a specific nature made of specific attributes” (AS 1016). On that page, it is clear that she takes for entities not only what are ordinarily called objects such as leaf, stone, or table, but micro-objects such as living cells and atoms, and super-objects such as solar system and universe.

Now we have a modest problem. If we say “to exist is to be an entity of a specific nature made of specific attributes,” we seem to say that attributes are either entities or are not existents. Consider for attributes “the shape of a pebble or the structure of the solar system” (AS 1016). To avoid the patent falsehood that the shape of a pebble does not exist, shall we say that not only the pebble is an entity, but its shape is an entity? Rand reaches a resolution by a refinement in her metaphysics nine years after her first presentation. In 1966 she writes “Entities are the only primary existents. (Attributes cannot exist by themselves, they are merely the characteristics of entities; motions are motions of entities; relationships are relationships among entities)” (ITOE 15). In Rand’s view then, we have that to exist is either (i) to be an entity consisting of particularities and specific attributes and a specific nature or (ii) to be some specific character in the nature of entities or among an entity’s particularities.

Philosophers often use the term entity to mean any item whatever. That is one customary usage and perfectly all right. Rand decided to take entity into her technical vocabulary as something more restricted. She went on to name some fundamental categories that cannot exist without connection to entities: action, attributes, and relationships.[1] As with Aristotle’s substance (ousia), where there is any other category, there is entity to which it belongs.[2] Though Rand held entities to be “the only primary existents,” she did not suppose entities could ever exist without their incidents of action, attributes, and relationships. To trim away, in thought, all the internal traits of an existent as well as all its external relations should in right thought leave no existent. Out of step with Aristotle, Rand did not maintain there is such a thing as an entity that is a what, yet is without any specification by other categories of existents.[3]

Entities have relations to other entities, but not the belonging-relation (inherence) had to entities by the categories not entity. The entity that is the sofa is in a region of the living room and it is in a force-relation with the floor. But it is not in anything in the way its shape and mass and stability and flammability are in it. Though she held actions, attributes, and relations to be incapable of existing without the entities of which they are incidents, Rand did not import to entity Aristotle’s concept of substance as somehow imparting existence from itself to the other fundamental categories.

In Rand’s view, all of those categories have some instances in concrete existents. Actions, attributes, and relationships are not entities in Rand’s sense. To qualify as an entity, I say and think Rand could have been brought around to say, an entity has to do more than be able to stand as the subject of predication (or as the argument of a propositional function). Running or oscillation can be the subjects of predicates, but they can do so as actions, not entities. Fraction and containment can be the subjects of predicates, but they can do so as relations, not entities. Twill and vesicular quality can be subjects of predicates, but they can do so as attributes, not entities.

Rand’s entity as primary existence parallels to some extent Aristotle’s ousia as primary being. Entity as subject of attributes, actions, and relationships parallels Aristotle’s ousia.[4] Substance has been the most common translation of Aristotle’s ousia, when used as the fundamental form of being. Joseph Owens argues that the traditional translation of Aristotle’s ousia is poorly conveyed by substance and is better expressed by entity.[5] Joe Sachs argues for the more Heideggerean translation thingness for ousia.[6] In whatever English translation, Aristotle’s full conception of ousia in his Metaphysics is far from Rand’s conception of entity.

Entity does not stand as of-something. In that respect, it is like Aristotle’s ousia. Unlike his ousia in Metaphysics, entity as such is never the essence of something. Also contra Aristotle’s being that is ousia, the existents that are entity can have parts that are entity. Furthermore, as noticed earlier, unlike the accidents of Aristotle’s ousia in Metaphysics, the existence of incidents does not derive from the existence of entity.[7] Existents of the incidents are coordinate with existence of entities, not derivative from nor secondary to existence of entities.

In contrast with Aristotle, Rand’s entity, primary form of existence, is only of this whole of existence, our spatial-temporal world, with both its actualities and its potentials, and our understanding over it. That is the all-encompassing reality. Contraction of being to existence includes a denial that there are metaphysical perfections and denial that there is such a thing as unqualified being. Such perfections, and unqualified stuff, when added together with existence per se constitute Aristotle’s being. Aristotle has Rand’s entities as occasions of ousia, at least prima facie, and these he calls natural ousia.[8] Aristotle’s primary ousia, fundamental form of being, I should add, is always an individual, a this something, though not always a concrete.[9] 

“Substance is on the one hand, matter, on the other hand, form, that is, activity” (Metaph. 1043a27–28).[10] Shape, such as shape of a bronze statue, is not all Aristotle means here by form (mophê). That which explains the coming to be of the statue from unshaped bronze is here included as form; then too, form is here determining principle of which the bronze constitutes this statue rather than any other being. Bronze of itself is determinate matter, but as matter of this statue, it is this form’s matter in consideration of its potential to be another form’s matter. For Aristotle explanation of substance requires both matter and form. Like most all moderns, Rand and Peikoff reject Aristotle’s fundamental form/matter division of all beings.[11]

Aristotle had ousia not only primary in account of the kinds of being, but prior in time to them.[12] In the shift from being to existence as most fundamental and in the shift from ousia to entity as most fundamental category of existence, we do not conceive of entity as temporally prior to attributes and relations. For the move from being to existence as most fundamental is move to existence already with identity.

If existence is identity and most fundamentally concrete, then entity is identity and most fundamentally concrete. Let us say further that entity is identity, essential and inessential. Essential identity of an entity is identity without which the entity would not be the kind it is.[13] To say that entity is essential identity might seem close to Aristotle’s view that ousia and its essence are one.[14] Rand’s principle existence is identity has greater scope than Aristotle’s ousia is its essence. For her existence is identity has comprehensive scope: it spans not only entity and its essential attributes, but its entire suite of attributes, as well as its standings in actions and relations.

For Aristotle capturing what is a specific ousia—where ousia is the primary form of being and the subject of attributes and alterations—requires formulating its definitions such that the essence expressed in the predicate (definiens) has a uniquely right necessary tie and has explanatory tie with the subject (definiendum). Without that essential trait, the ousia defined could not be the kind of ousia it is. Furthermore, if no such trait can be found, the subject is not an ousia, a what-it-is, but a depending quantity, quality, relation, time, location, configuration, possession, doing, or undergoing.[15]

In Rand’s modern metaphysics, capturing best what is a specific entity requires formulating its definiens such that it has a right, necessary, and explanatory tie with the subject entity. The unity of essential characteristics with existence of the entity to which they belong are not absolute in the way Aristotle’s specific essence belongs to specific ousia. His is an ascription right independently of context of knowledge. Rand’s theory of essential characteristics for definitions allows for evolution as our knowledge context grows.[16] Furthermore, unlike Aristotle’s theory, the unity of the essential in definitions of existents is just as tight where those existents are attributes, actions, or other relations as when the existent being defined is an entity.

The essence of Newtonian force is expressed in its definiens, with specific mathematical defining formula relating certain physical quantities. Special relativity recasts that fundamental defining equation of force, the old equation imbedded in a more elaborate one taking newly learned factors into the account of force.[17] Contrary Aristotle, existents not substance and not entity can have essential characteristics, and these are a function not only of what is so, but of what it is we know of what is so. Although Rand made essential characteristics dependent on context of knowledge, these characteristics are real, the dependencies (such as causal or mathematical) other characteristics have upon them are real, and the explanatory character of essential characteristics vis-à-vis other characteristics is objective.

Additional likeness and difference in the metaphysics of Rand and Aristotle are the following. In the metaphysics of Aristotle, when we grasp the essence of ousia, we become that essence; such an assimilator is what is a mind.[18] In Rand’s metaphysics, our grasp of an essence is an identification of an identity; such an identifier of identity is what is a mind, although essence is not the only identity of the existent determining mind, and as mentioned, entity is not the only category in which there are essential aspects. Furthermore, unlike the metaphysics of Rand and other moderns, the metaphysics of Aristotle has it that essence is only in kinds of ousia (kinds of substance/entity) such as the kind man. The essence of man—rational animal—exhausts the kind man. Aristotle recognizes, naturally, that the individual man is more in particulars and specifics, more than the essence and ousia. Rand has it rather that the kind is only a class of individuals, each with all their identity, and essential characteristic(s) of the class concern causal and other explanatory relations, identities that are categories not only the category entity.

Rather than her loose and overlapping categories of action, attribute, and relation, Rand could have conceived of them as mutually exclusive categories by confining attributes to traits not essentially in relation to other things and by confining relations to features not monadic and not action. It would remain, however, for her selection of fundamental categories that electric current, for example, could be (a) an attribute of an active conducting wire, manifest by shock or by resistance heating of the wire, and (b) a flow of electrons within the wire and (c) a source of the magnetic field around the wire. Assignment to a Randian category, unlike an Aristotelian one, should, I think, remain dependent on the physical situation under consideration. In the present example: (a) attribute, (b) action, (c) entity. In Rand’s fully developed theoretical philosophy, as I mentioned, essential characteristics, though factual, are functions of the human context of knowledge.[19] If we extend functional dependence of essential characteristic to context of consideration, then multiple highest genera of an existent is not problematic, unlike the circumstance for Aristotle with his metaphysically absolute essences, ever the same whatever our level of knowledge and context of consideration.

Notes

[1] AS 1016; ITOE 7, appx. 264–79.

[2] ITOE appx. 157, 264; Aristotle, Cat. 2b3–6; Metaph. 1028a10–30. Aristotle maintained two sorts of substance, primary and secondary. The former would be an individual such as the individual man Parmenides; the latter would be the species or genus of such an individual. Rand’s entity is always only a concrete individual.

[3] Aristotle, Metaph. 1028a30–b3. See further, Pasnau 2011, 99–102.

[4] ITOE 15; Aristotle, Cat. 2a14–19; Cael. 298a26–b3; Metaph. 1028a10–b7.

[5] Owens 1978, 137–54; see also Gotthelf 2012, 8n11. What is traditionally translated as being in Aristotle, is sometimes translated as existence; Barnes 1995, 72–77. Here again, we must not let that dull us to the differences between Aristotle and Rand on the concept in play.

[6] Sachs 1999, xxxvi–xxxix.

[7] Aristotle, Metaph. 1045b27–33; Lewis 2013, 13–15, 91.

[8] Cael. 298a26–b3; Metaph. 1017b10–15, 1028b9–32, 1040b5–10, 1042a7–11.

[9] Cat. 3b10–23; Metaph. 1028a12, 25–30.

[10] A. Kossman, translator.

[11] ITOE appx. 286. Koslicki 2018 offers a modern defense of Aristotle’s hylomorphism.

[12] Aristotle, Metaph. 1028a32–33.

[13] Top. 101b37; Metaph. 1025b11, 1029b14–16 ; ITOE 42, 45, 52.

[14] Metaph. 1031a28–1032a5; see also Top. 135a9–12; further, Witt 1989

[15] Cat. 1b25–2a; Top. 103b20–25; Metaph. 1028b1–3.

[16] ITOE 40–52.

[17] What force is in our contemporary physics is also informed by the setting of force in relation to Hamiltonian mechanics, a more general classical mechanics having natural joins with quantum mechanics. Newton’s gravitational force, whose definition requires its fundamental equation, is also recast by situating it in the deeper successful theory that is general relativity.

[18] Aristotle, De An. 429a10–430a26.

[19] ITOE 43–47, 52.

References

Aristotle c.348–322. B.C. The Complete Works of Aristotle. J. Barnes, editor (1984). Princeton: Princeton University Press.

Barnes, J. 1995. Metaphysics. In The Cambridge Companion to Aristotle. Cambridge: Cambridge University Press.

Gotthelf, A. 2012. Teleology, First Principles, and Scientific Method in Aristotle’s Biology. New York: Oxford University Press.

Koslicki, K. 2018. Form, Matter, Substance. New York: Oxford University Press.

Owens, J. 1978 [1951]. The Doctrine of Being in the Aristotelian Metaphysics. 3^rd ed. Toronto: Pontifical Institute of Medieval Studies.

Pasnau, R. 2011. Metaphysical Themes 1274–1671. New York: Oxford University Press.

Rand, A. 1943. The Fountainhead. Indianapolis: Bobbs-Merrill.

——. 1957. Atlas Shrugged. New York: Random House.

——. 1966–67. Introduction to Objectivist Epistemology. In Rand 1990.

——. 1990. Introduction to Objectivist Epistemology. Expanded 2^nd ed. H. Binswanger and L. Peikoff, editors. New York: Meridian.

Sachs, J., translator, 1999. Aristotle’s Metaphysics. Santa Fe: Green Lion Press.

Witt, C. 1989. Substance and Essence in Aristotle. Ithaca: Cornell University Press.

[merjet]

Edges, Entities and Existence

This essay, which contains a lot about Ayn Rand's ideas about entities, was presented at The Objectivist Center's (now The Atlas Society) Advanced Seminar in 2000.

There is nothing about Aristotle's substance (ousia). It's long.

[Boydstun]

David J. Jilk discussed the category entity in his paper “What Are Entities?” (2003).

His paper takes into account aspects of what Rand, Peikoff, Kelley, and Ray & Radcliffe (which Merlin linked in the preceding post) had written on this Randian conception.

The Ray and Radcliffe paper addresses aspects of Rand’s conception that Rand did not write up and publish. Rand expressed these aspects in informal oral discussion (1969–71) that is transcribed in the Appendix added to the reissue (1990) of Rand’s monograph “Introduction to Objectivist Epistemology” (1966–67).

On importance of conceiving mind as an entity, see Roger Bissell’s paper “Mind, Introspection, and ‘The Objective’” (2008).

Entity is also an ontological category in my own metaphysics related to Rand’s. My category Entity is moderately broader than Rand’s, and this is an ontological broadening, not anything from consideration of variety in perspectives possible to consciousness. My category Entity is set out in my paper presently under review at JARS. In my root post of this thread “Entity and Ousia” I treated only Rand’s category entity in relation to Aristotle’s ousia. So the treatment I have made here concerns purely the Objectivist philosophy, nothing of my own related one.

In connection with my Rand/Aristotle study here, compare in the future whatever comes to be written in a book in progress comparing Rand and Aristotle in the series Ayn Rand Society Philosophical Studies.

Drawing from the remarks of Rand in the ITOE appendix, Jason G. Rheins conveys the following within his “Objectivist Metaphysics” (2016).

Quote

Rand was intentionally flexible in her usage of the term “entity.” Unlike Aristotle, she does not limit entities to everyday sized objects (and god), nor claim that natural entities are more fully entities than artificially crafted ones. What counts as an entity will vary from context to context, and Rand was prepared to call any combination or conglomeration of other entities “entity” as well, so long as there was something uniting is parts in such a way that there is something we could learn about that “entity” as a whole. The unity need not be physical: it could be glue sticking together a pile of dirt to make it a “clod,” . . . Similarly, she would call any part of an entity an entity, so long as there were some informative basis for distinguishing it from other parts of the whole. Whether there is such a basis is not determined by a general metaphysical rule or principle of individuation. It does not depend on an a priori rule about spatial distinctness, for example. . . . It is an epistemic judgment, specific to that context, of whether the factors uniting or dividing suffice to make it worthwhile to refer separately to that part or conglomeration, and thus call it an “entity.” (255)

I imagine, however, there remains the necessary-condition rule for the Objectivist category entity, parallel Aristotle on ousia, that entity does not stand in an inherence relation to any other category, whereas all the other categories stand in an inherence relation to entity.

See also Gotthelf 2000, 39–40, 45.

Note, incidentally, Rand's remarks about animal consciousness rising to the level of percepts, therefore to awareness of some entities in “The Objectivist Ethics.”

Edited June 3, 2020 by Boydstun

[Boydstun]

Oral exchange, from seminar, transcribed in Appendix of ITOE second edition.

Leonard Peikoff -  “Would it be fair to say that a concept qua concept is not a concrete but an integration of concretes, but qua existent it is a concrete integration, a specific mental entity in a particular mind?”

Ayn Rand - “That’s right. But I kept saying, incidentally, that we can call them ‘mental entities’ only metaphorically or for convenience. It is a ‘something’. . . Anything pertaining to the content of a mind always has to be treated metaphysically not as a separate existent, but only with this precondition, in effect: that it is a mental state, a mental concrete, a mental something. Actually ‘mental something’ is the nearest to an exact identification. Because ‘entity’ does imply a physical thing. Nevertheless, since ‘something’ is too vague a term, one can use the word ‘entity’, but only to say that it is a mental something as distinguished from other mental somethings (or from nothing). But it isn’t an entity in the primary Aristotelian sense in which a primary substance exists.”

~~~~~~~~~~~~~~~~

Howard Robinson, in SEP, for “primary substance.”

[Boydstun]

In the References, I neglected to include Lewis 2013 which I had cited in Note 7:

Lewis, F.A. 2013. How Aristotle Gets By in Metaphysics Zeta. Oxford: Oxford University Press.

 

In the last paragraph of my study, I had written:

Quote

Rather than her loose and overlapping categories of action, attribute, and relation, Rand could have conceived of them as mutually exclusive categories by confining attributes to traits not essentially in relation to other things and by confining relations to features not monadic and not action. It would remain, however, for her selection of fundamental categories that electric current, for example, could be (a) an attribute of an active conducting wire, manifest by shock or by resistance heating of the wire, and (b) a flow of electrons within the wire and (c) a source of the magnetic field around the wire. Assignment to a Randian category, unlike an Aristotelian one, should, I think, remain dependent on the physical situation under consideration. In the present example: (a) attribute, (b) action, (c) entity.

Fred Miller notes in his 2018 translation of Aristotle’s On the Soul (and other psychological works):

Quote

Aristotle holds that something in one category such as quality cannot be an element of anything in another category such as substance (e.g. redness cannot be an element of apple, or vice versa) and that things in different categories cannot have the same elements (see Metaphysics XII. 4, 1071a31–b10 for argument.). (180)

 

[Boydstun]

Further Comparison of Their Metaphysics

Ayn Rand introduces her principle of identity and its exclusionary character with examples of physical entities being themselves not each other and examples of physical entities capable of contrary traits at different times, but not at the same time: “A leaf cannot be a stone at the same time, it cannot be all red and all green at the same time, it cannot freeze and burn at the same time” (1957, 1016). From the pervasiveness of such exclusionary identities in any existents, Rand proposed them as basis for non-contradiction being a pervasive right rule for us in identifying things. And she proposed the fact of exclusionary identities in all alterations as basis for the causal, lawful character of all alterations. ”The law of causality is the law of identity applied to action” (1037).

Aristotle would continue: A leaf changing from not frozen to frozen requires a leaf continuing to be a leaf across the alteration. Likewise a frozen leaf undergoing changes from being a frozen leaf to being a burning leaf has a leaf continuing to be a leaf across those alterations. When it comes to a leaf becoming ashes or a leaf becoming the impression of a leaf in sedimentary stone, there is no continuing leaf. There must be rather a stuff shared by both a leaf and its ashes or its stone impression. There must be a stuff undergoing alteration from leaf to ashes or stone. Let us have that stuff the same in all such alterations of one kind of thing into another, let us call such a stuff Prime Matter. A leaf may consist of veins and webbing, a man of bones and flesh, but both leaf and man ultimately consist of Prime Matter. By this postulation, we can avoid the absurdity that materials can come from nothing or pass into nothing  (Phys. 191a23–b17).

In Rand’s time and ours, we have no live use for such a conception as Prime Matter. In its place, we have a conserved mass-energy, in its particular exemplifications, across alterations of one kind of thing into another. Rand would have gotten education in principles of conservation in chemistry and the conservation of energy from physics of the nineteenth century. With those in hand, there is no need to worry that any physical transformations are taking elementary matter into nothing or taking elementary matter as arising from nothing.

Change of a leaf to ashes is a change from one kind of thing to a profoundly different kind of thing. As Aristotle casts it, that is a change from one substance to another substance. Call such change “substantial change.” In the transformation of leaf to ashes, Prime Matter has changed from one form to another. Call such forms of Prime Matter: Substantial Forms. All natural things are a composite of Prime Matter and Substantial Form on this view (as well as other levels of composite matter and form).

Mattered form is what a natural thing is, which form real definition aims to capture in the essence of what a thing is. Definition capturing what a thing is essentially, in Aristotle’s account, is capture of the metaphysical essence of a thing, which is a thing’s form. “By form I mean the essence of each thing and the {its} primary substance” (Metaph. 1032b1–2).

Rand rejected such a notion of metaphysical essence and form to be captured in real definitions. Rather, she took essential characteristics to be specified in real definitions as the most fundamental distinguishing real characteristics of a thing at a given stage of our knowledge. The implication of Rand’s metaphysics and epistemology is that identities in the world one has comprehended are not metaphysical unions of Prime Matter and Substantial Form (cf. Rand 1969–71, 286). Although Rand’s essential characteristic(s) in real definitions are explanatorily fundamental and sometimes that can be causally so, characteristics causally fundamental in relation to other characteristics of a thing are not causal as essences (Rand 1966–67, 52).

Among the types of causes according to Aristotle are ones called material and ones called formal. We do not use the concept cause so broadly today. We say that an electric current in a wire causes a magnetic field around the wire (that is an instance of efficient causality), but we do not say that the constitutive elements of an electric current in wire, such as free electrons in the copper wire are a “cause” of the electric current. We say that electrical potential difference between the ends of the wire cause (an efficient cause) free electrons to move and such movement is an electric current. 

Contrary my remarks* in Part 1 of my essay review of The Biological Basis of Teleological Concepts in which I obliquely endorsed a notion of material causes in nature, I say here and Objectivism should say: there are no material or formal causes in Aristotle’s sense for them for natural philosophy. Insofar as such causes are metaphysical dynamics underlying physical dynamics, they should be rejected, as dynamical metaphysics should be rejected. Insofar as material or formal causes in Aristotle’s sense are passive constituents of things or potentials of actuals, these too should be rejected as causes.

References

Aristotle c.348–322. B.C. Physics. C.D.C. Reeve, translator. 2018. Indianapolis: Hackett.

——. Metaphysics. C.D.C. Reeve, translator. 2016. Indianapolis: Hackett.

Rand, A. 1957. Atlas Shrugged. New York: Random House.

——. 1966–67. Introduction to Objectivist Epistemology. In Rand 1990.

——. 1969–71. Rand’s Epistemology Seminar. In Rand 1990.

——. 1990. Introduction to Objectivist Epistemology. Expanded 2^nd ed. H. Binswanger and L. Peikoff, editors. New York: Meridian.

 

 

Edited September 25, 2023 by Boydstun

[Boydstun]

22 hours ago, Boydstun said:

. . .

Change of a leaf to ashes is a change from one kind of thing to a profoundly different kind of thing. As Aristotle casts it, that is a change from one substance to another substance. Call such change “substantial change.” In the transformation of leaf to ashes, Prime Matter has changed from one form to another. Call such forms of Prime Matter: Substantial Forms. All natural things are a composite of Prime Matter and Substantial Form on this view (as well as other levels of composite matter and form).[1]

Mattered form is what a natural thing is, which form real definition aims to capture in the essence of what a thing is. Definition capturing what a thing is essentially, in Aristotle’s account, is capture of the metaphysical essence of a thing, which is a thing’s form. “By form I mean the essence of each thing and the {its} primary substance” (Metaph. 1032b1–2).[2]

. . .

I’ll add a couple of Notes and the References.

Notes

[1] Attribution of this conception of a Prime Matter to Aristotle goes as far back as Augustine and Simplicius, similarly was it adopted by Avicenna and continued and cemented by Aquinas, and it is predominate among Aristotle scholars to the present. A minority view takes Aristotle as not holding to a bare-substrate (Prime Matter) theory of substantial change, but a compresent-properties view without substrate (Lewis 2009, 180).

[2] James Lennox argues that Aristotle on balance is best seen as including matter as well as form in the definitional accounting of the matter/form composite that is natural body (Lennox 2015, 18; 2021, 137–39; cf. Jetton 1991, 5, here). 

References

Anagnostopoulos, G., editor, 2009. A Companion to Aristotle. Chichester, West Sussex: Wiley-Blackwell.

Aristotle c.348–322. B.C.E. Physics. C.D.C. Reeve, translator. 2018. Indianapolis: Hackett.

——. Metaphysics. C.D.C. Reeve, translator. 2016. Indianapolis: Hackett.

Jetton, M. 1991. Philosophy of Mathematics. Objectivity 1(2):1–32.

Lennox, J.G. 2015. How to Study Natural Bodies. In Leunissen 2015.

—. 2021. Aristotle on Inquiry. Cambridge: Cambridge University Press.

Leunissen, M., editor, 2015. Aristotle’s Physics – A Critical Guide. Cambridge: Cambridge University Press.

Lewis, F.A. 2009. Form and Matter. In Anagnostopoulos 2009. 

Rand, A. 1957. Atlas Shrugged. New York: Random House.

——. 1966–67. Introduction to Objectivist Epistemology. In Rand 1990.

——. 1969–71. Rand’s Epistemology Seminar. In Rand 1990.

——. 1990. Introduction to Objectivist Epistemology. Expanded 2^nd ed. H. Binswanger and L. Peikoff, editors. New York: Meridian.