Notes to Chapter 3 of Zabarella’s De Mente Agente

Main topics covered: Aristotle’s theory of vision, intromission and extromission theories of vision, the relationship between perception and the intellect, the signification of the term “habitus”/hexis, hexis in relation to ethics, the relationship between the intellect as a hexis as a “maker” and as a “form,” efficient causality and the intellect, Aquinas and species as moving causes of intellection.

Note 1:  The term “motiva” might well seem to come in oddly here and it might even be wondered whether this is a reference to the extramission theory of vision that was widely accepted during the renaissance, since the analogy clearly pertains to the conditions necessary for sight (for two sources on the history of theories of vision, see below). However, Zabarella discusses the Aristotelian explanation of vision in terms of movement following Aristotle’s text, the main points of which are to be found in De Anima II.7 at 418b1:

Every color has in it the power to set in movement what is actually transparent;

at 419a9-10:

At present it is obvious that what is seen in light is always colour. That is why without the help of light colour remains invisible. Its being color at all means precisely its having in it the power to set in movement what is actually transparent, and the actuality of what is transparent is just light.

and again at 419a13-15:

Color sets in movement what is transparent, e.g. the air, and that, extending continuously from the object of the organ, sets the latter in movement. (1)

These three texts provide us with the basics of Aristotle’s theory of vision, according to which the color of an object acts upon an illuminated medium (i.e. the otherwise unoccupied translucent field of air between the eye and the visible object) to effect a change in the sense organs, which it accomplishes by means of a movement it produces within the medium.  Finding the eye to contain a watery substance, Aristotle thought that the water in the eye was susceptible of carrying the movement produced by the color of an object, so that it, in turn, produced sight within the eye (cf. De Sensu et Sensibilia, 438b where Aristotle makes explicit that the eye is capable of admitting light and that the eye is the proper site of the conjunction of the power of vision with what it seen-something that according to the Platonic extromissionist theory, required the emission of light outside the organ of the eye itself).

In line with the Aristotelian view, when commenting on the first quoted text above, Zabarella writes that the illuminated medium of vision is that “per quod fit actio obiecti in sensum hoc enim erit progredi ab obiecto ad operationem” (in Textus 68, page 119 (pdf pp. 336ff.)). Here the medium might be thought of as a necessary condition for action on the senses to take place and for them to be made active. Later in commenting on the same text, he writes that a property of color is that it is able to set a transparent medium in motion. Interestingly, he goes on to say that the precise way in which it causes this motion is by imprinting its “species,” its (potentially visible) form upon the medium of vision:

Movere autem perpsicuum nil aliud eft, quam imprimere in eo speciem suam, quae est alteratio perspectiva, de qua in praecedentibus dictum eft

Zabarella’s commentary therefore follows closely the Aristotelian version of the intromissionist theory  of vision, according to which the “eidos” (image, idea, form) of an image is transfered to the eye itself.

Attention to the elements in this theory (agent, patient, object) helps to clarify the way in which sight is analogous to thought and is Zabarella’s main preoccupation here.  The analogy is directly applicable to De Anima III.4, where Aristotle, in comparing the mind to the sense organs, says that it must be  capable of receiving the form of an object, so that it is potentially identical to its object without being its object (cf. 429a15-17):

ἀπαθὲς ἄρα δεῖ εἶναι, δεκτικὸν δὲ τοῦ εἴδους καὶ δυνάμει τοιοῦτον ἀλλὰ μὴ τοῦτο, καὶ ὁμοίως ἔχειν, ὥσπερ τὸ αἰσθητικὸν πρὸς τὰ αἰσθητά, οὕτω τὸν νοῦν πρὸς τὰ νοητά. (See the tlg for an online greek text)

I translate:

[The potential intellect] “Must be impassive, but receptive of the form and potentially such [i.e. as the form] while not becoming the former and to be of such a nature that, just as the sense organs are related to what is sensible, so the intellect is related to what is intelligible.”

In the text that follows, Zabarella distinguishes the role the agent intellect plays in the process of making potentially intelligible objects actually intelligible. His primary claim here is that, while it may be considered an agent, its action upon potentially intelligible objects is such that it involves the contribution of a form-light-that makes them actually intelligible.

(1) These are translated by J.A. Smith, in The Complete Works of Aristotle, The Revised Oxford Translation, Edited by Jonathan Barnes, vol.1, Bollingen: 1995, pp. 666-667.

Note 2: Zabarella is here referring to De Anima III.5 430a15, where Aristotle writes that the agent intellect that makes all things is kind of “disposition,” like light:

καὶ ἔστιν  μὲν τοιοῦτος νοῦς τῷ πάντα
γίνεσθαι δὲ τῷ πάντα ποιεῖνὡς ἕξις τιςοἷον τὸ φῶς·

The term habitus translates into Latin the Greek term ἕξις.  One difference between the two is that “ἕξις” is a substantive formed from the future tense of the verb “to have,” (thus “will have”) whereas habitus is a substantive apparently coined by Aristotle’s Latin translators directly from the past participle of the verb “to have, hold” (thus “has had”)  and has “clothing” or “garment” one puts on as a synonyms, whence we get the word “habit.” Thus, in Greek it signifies a “will have” and something one “has obtained” or “holds” or perhaps metaphorically, “puts on” in the Latin. In either case, in ethical contexts, the term ordinarily conveys the idea of an disposition to act in a certain way that is not easily acquired and that is kind of addition to one’s given nature. Aristotle commonly uses the term διάθεσις as a synonym (cf. for example Metaphysics V.20 where Aristotle discusses the definition of ἕξις), which can be analyzed morphologically into the notion of “directedness to an end” (διά) and a “placing,” “setting down,” or “positioning,” thus conveying the idea of an orientation to something.

In the context of Aristotelian ethics, the term fits neatly into the framework of character development as a fulfillment of one’s nature. For this reason, some have taken issue with “habit” as a translation in such contexts, since it does not adequately distinguish between the kind of “habit” (if the term fits at all) that is acquired by accident and one that is established deliberately in the attempt to attain some particular kind of excellence (See, for example, J.J. Glanville’s discussion of the term in The Material Logic of John of St. Thomas, p. 611, note 5, pdf page 641).  In the present context, a habitus refers not to an acquired, but to an innate disposition, however, making “disposition,” or perhaps even “faculty” or “power” better choices.

But the term can also be used more broadly to indicate the polar opposite of a privation (cf. Metaphysics, Book 10.4, 1055a33, whether referring to a natural state or to an acquired one.  In Categories 12a36, Aristotle uses the term to describe the possession as opposed to the privation of sight. There may be a sense in which the semantic richness of the term can be brought out with reference to the contrast between the potential and agent intellect in this respect: one represents the possession of a disposition toward a certain kind of activity, whereas the other represents its polar opposite: a privation of any ability to actualize knowledge on its own.  Furthermore, in the soul as a whole, the agent intellect is a habitus in the sense of being a disposition like sight, but also represents a natural ability that is the basis for further acquired abilities that lead to excellence.  In this sense it is a natural disposition such as the hand naturally has, to make things, being its intellectual counterpart, as Aristotle writes in De Anima III.8, 432a1-2,

ὥστε ἡ ψυχὴ ὥσπερ ἡ χείρ ἐστιν· καὶ γὰρ ἡ χεὶρ ὄργανόν ἐστιν ὀργάνων, καὶ ὁ νοῦς εἶδος εἰδῶν καὶ ἡ αἴσθησις εἶδος αἰσθητῶν.

“So that the soul is like the hand: for even as the hand is the tool of tools, so too the intellect is the form of forms and perception is the form of  perceptions”

(My trans.)

Extending this consideration to the ethical realm, it is a possession of the soul that, in making all things, is of even more fundamental importance than the hand, as that without which wisdom, practical or otherwise, could not be acquired.


*The Greek texts quoted from the de Anima and Metaphysics here are taken from Ross’s critical editions, while the Categories quotes from the 1949 Oxford edition of Aristotle’s works.

L. Minio-Paluello, Aristotelis categoriae et liber de interpretatione, Oxford: Clarendon Press, 1949 (repr. 1966): 3-45 (1a1-15b32).

W.D. Ross, Aristotle. De anima, Oxford: Clarendon Press, 1961 (repr. 1967)

W.D. Ross, Aristotle’s metaphysics, 2 vols., Oxford: Clarendon Press, 1924 (repr. 1970 [of 1953 corr. edn.]): 1:980a21-1028a6; 2:1028a10-1093b29.

Note 3: In his treatise, De Speciebus Intelligibilibus (see pdf p.730), Zabarella attributes the view that species impressa, i.e. the forms of things that have been “impressed” upon the intellect in the same way that visual forms affect the eye, act as an efficient, motive cause of intellectual activity (sp. apprehending the “forms” of things) to Aquinas and Zimara, who he says followed him in his opinion on the issue:

sic igitur species intelligibilis impressa in intellectu est ratio formalis, qua intellectus operatur.; non operatur autem, nisi a phantasmate moueatur, ideo phantasma lo- cum habet obiecti mouentis

sed opinionem Thomae sequi videtur Zimara in theoremate. 82. vbi afferit fpeciem in intellectu impressam esse principium effectivum intellectionis, hoc eft rationem formalem, qua intellectus, qui possiblis dicitur , est intellectionis productivus .

For Aquinas, he references Commentary on the De Anima, Book III, Commentary 8 and the Summa Theologiae, I,85 as textual sources.

Thus, Zabarella distinguishes the causal role of the agent intellect from that of the object of thought, which might be supposed to move one to think. In fact, it acts upon the object in such a way that, according to the analogy, it brings to it the form of light, a “perfection” of the colors themselves, making potentially visible colors into actually visible (i.e. intelligible). Such a light would not thereby alter the nature of such colors, but make them actually visible inasmuch as they are already potentially visible (Aristotle says that it is specifically being colored that makes objects visible, with light as a further necessary cause-see references to note 1 above).


See pdf pg. 730 or pp. 686-7 of Zabarella’s De Speciebus Intelligibilibus  in the collection, De Rebus Naturalibus,  Venice: 1590.


A Dialogue on Lockean Substratum

The following link is to a dialogue I wrote up on Lockean substratum.  You have to click on the link to see the PdF file.  I wrote it out long hand in a cafe since I have been experiencing technical difficulties with my laptop.

Dialogue on Lockean Substratum


Opinion on the notion of Substratum

Opinion: better alternatives than Aristotelian substratum may be found to ground the existence of the attributes of substances. One such is presented here, which is put forward as logically consistent and one that satisfies both the demands of Aristotelians and their Empiricist opponents.

The Issue~

Before Tina Turner sang, “We don’t need another Hero” Locke wrote in a similar way about the non-necessity of Aristotelian substratum. Why did people think that everyday objects needed a substratum to be sufficiently groundedontologically? Well, the reasoning can be taken as proceeding like this:

When we look at everyday objects, we can see that they have certain attributes, such as a certain height or color or weight.
These attributes can be said to have a certain order of dependence one upon another: for example, an object has a color only if it first has extension in space. Only if an object is extended in space, having at least two dimensions, it might be said, can it thereby have a color. This is true even in one’s imagination. Necessarily, if an object has a color it has a height and width, if not a depth and weight at a certain time.
But, the advocate of substrata would claim, extension is not enough to establish an object as a real entity by itself. Being a mere attribute of an object it cannot exist on its own.
The justification for #3 is related to #2 in the sense that it involves ontological dependence. This time the dependence is spoken of in terms of “inherence”. The argument goes as follows: (a) the qualities of an object such as its colors, which are a type of accident (see #1) cannot exist on their own without belonging to or inhering in a substance; (b) in the same way, the quantitative accidental attributes of a substance, such as its height or weight or length cannot exist apart from an object. Moreover, (c) the qualities and quantitative attributes of an object make up the sum total of an object’s internal attributes (i.e. those that are not relative and depend upon its internal attributes). But (d) all such attributes must inhere in something since they cannot exist on their own (see a-c). Hence (e) all such attributes must depend upon a further something that might ground their existence. That further something is what the Aristotelian would call a substratum.
The claim that this argument can be taken as a synopsis of the Aristotelian view on “Substance” perhaps needs some defense. This can be presented briefly, but I think conclusively, as follows.

The word Aristotle uses that is usually translated as “substrate” in the Categories is to hypokeimenon, or literally, “the underlying (something)”, which is often translated as “subject” (as in the grammatical subject of predicates). It should be seen at the outset that the term does double duty in the Categories as a term for a grammatical subject (as a subject for predicates) and for a subject in the sense of substance: e.g. Aristotle writes in Chapter 2 of the Categories, “By being ‘present in a subject’ I do not mean present as parts are present in a whole, but being incapable of existence apart from the said subject.” By introducing the notion of accidents as existing in a substance (the Greek word here is hypokeimenon as above) Aristotle is in effect shifting the ontological ground of his discussion from the consideration of the role of a subject as a bit of grammar to subject as a countable entity.

The effect is such that the discussion of the hypokeimenon-subject of the second chapter of the Categories naturally bridges over into Aristotle’s further discussion of ousia-subject in the fifth chapter. It is significant that Aristotle has an entitative sense of “subject” in mind in the second chapter because it lays the foundation for a dualism between substance and accident that follows from his claim (quoted above) that accidents cannot exist on their own (chapter 2), although a substance can (implicit in chapter 2 where he identifies subjects as unitary things such as individual horses and men in contrast to things that are present in a subject, and explicit in chapter 5 where Aristotle says that the ability to subsist is one of the primary differentiating characteristics of a substance).

The non-reducibility of accident to substance follows from this duality: one subsists while the other merely “exists in” (see 4 a and b above). But this in turn yields the further result that no collection of accidents can yield a substance. This reasoning is, quite arguably, implicit in Aristotle’s distinction between accidental and substantial change in the first Chapter of his lectures on Physics. It is this non-reducibility that provides the basis for the Lockean critique of Aristotle’s notion of substance.

It is, of course, fairly well established that Locke, in the end, decides to keep substrata in his inventory of “the things that are”. But he does so only after presenting a very compelling empiricist counterargument that has left many wondering whether he could actually be serious about maintaining that there are such things as substrata in the universe. His counterargument can be related to the dualism between substance and accident mentioned above.

Essentially, Locke’s argument works on the irreducibility of accident to substance that underlies that dualism. In Book II, ch. xxiii of his “Essay” Locke points out that if it were asked wherein qualities (secondary qualities) inhere in a substance one could answer that they inhere in the quantitative features of an object (in Locke’s terminology, their primary qualities). But if one were to press further and ask wherein the primary qualities of an object inhere, one could only answer that it must be an unknown something-something the senses do not perceive. It can be seen here that Locke is attempting to be a consistent empiricist in claiming that the notion of substratum is unfounded: since it cannot be sensed, it violates the basic criterion for what any good empiricist would accept into his or her ontology.  This type of argument might be called the “Indian argument” for short, since it has been referred to as such in the secondary literature.

Thus, the issue substratum theory poses comes to this: one can either say with Aristotle that a substratum is necessary as a ground or support for things that cannot exist on their own, or one can side with Locke’s empiricist argument against substrata (the indian argument) in saying that no such entity can be admitted into one’s ontology on empiricist grounds. Moreover, to admit substrata into one’s ontology is implicitly to move from a monistic position (materialism or phenomenalism) to a dualistic one (materialism plus an immaterial entity): since only “qualities” in Locke’s terminology, or “accidents” in Aristotle’s can by their very nature, be perceived, substrata, or substances without attributes must be taken to be imperceptible by their very nature. Hence it follows that for the substratum theorist, there must be at least two basic kinds of things: those that are perceptible and those that are imperceptible by their very nature. In admitting substrata into his ontology, Locke basically affirmed his commitment to a kind of dualism that in many respects mirrored Cartesian dualism, and for similar reasons (e.g. non-reducibility), has engendered dissatisfaction ever since.


The argument I would like to advance in response to this issue is that it is unnecessary to suppose substrata as a ground for accidents/qualities. This position prompts two lines of inquiry: firstly, can the quantitative features of an object exist on their own or do they require something wherein they may exist? I.e., how does one overcome the common sense view that says things like a particular height or weight must inhere in an object in order to have any reality? Does this not inescapably prompt the need to suppose the existence of a substrate wherein their existence may be grounded? Secondly, if the quantitative features of an object can somehow be taken to be the fundamental ground of being of an object and this in turn implies either a materialistic or phenomenalistic monism, can such a monism do all the metaphysical work the alternative dualism with its supposed substratum was able to do? An affirmative answer to the latter question can be justified through resolving the problems posed by the first line of inquiry: basically, a satisfactory monism will be able to do all the metaphysical work that the alternative dualism was able to do without supposing a fundamentally imperceptible substratum. Since substrata have this characteristic, they would seem to deserve the title of “occult entity” as much as any others of the same ilk and their elimination would seem to be desirable from both an epistemic and an empirical point of view if one happens to be committed to empirical principles in drawing up the inventory of one’s ontology. Let’s proceed then to see what can be done to eliminate substrata.

Supporting arguments~

Simply put, the key to eliminating substrata is to let the term “substance” indicate an entity that essentially includes all its attributes (or qualities or accidents) in its concept. This might be taken to be a Leibnizian view of substance. The next move is to see that, taking on the idea of the attributes of a substance as fundamentally dependent beings, they imply a substance. Thus, we are left with the following set of logical relationships between substances and their attributes: necessarily, if there is an attribute, then there is a substance; but, moreover, only if there is a substance can there be an attribute. If one wants to know wherein an attribute exists, it may be answered that it exists in or belongs to a substance; but only if there is a substance may there be an attribute at all. The latter justifies the idea that substance can function as the ground of existence for attributes, while the former affirms the basic desire to say that attributes must exist in something other than themselves.

This view of things fits perfectly well with any empiricist/phenomenalist view of perception that begins with particular percepts as a basic epistemic starting point. Consider an object; let’s say, a book, for example: the book may be considered a substance, while its color or height may be considered as belonging to it as a substance. The substance in this case is an independent entity but not one that is devoid of attributes. Indeed, as above, the existence of substance can be taken to pre-suppose the existence of attributes in a non-circular manner. Here again, the perceptible phenomenal attributes belong to the book as to a substance that grounds their existence; but that substance in turn sufficiently implies the existence of at least one attribute.

This may seem rough and ready given the long standing persistence of this metaphysical issue. But it should be enough merely to ask the reader to consider the logic that prompts the series of moves presented above. Consider that in posing the definition of substance presented here (seemingly out of thin air?) as an alternative to substratum theory, what has been shown is the non-necessity of substratum theory, provided that the version of the relationship between substances and their attributes is not self contradictory and can be said to be basically sound. The two paragraphs immediately above can be taken as answering to both of those requirements.

The desire to reify substance, to make it into a separate entity apart from its attributes, seems to follow from a mistake in thinking that whatever substance is, it must be something independent not only from other substances but also from its own attributes. It might be thought, for example, that since a substance may undergo a change in its attributes (for example changing from short to tall) it must be independent from its attributes. But this assumption is non-necessary from a logical standpoint: it may be said, alternatively, that substance sufficiently implies the existence of at least one attribute while the existence of an attribute necessarily implies a substance. Moreover, the irreducibility arguments above for an independent substance need only lead to the conclusion that a substance should be distinguished from its attributes from a conceptual standpoint: clearly, attributes must be fundamentally different from substances in some way, but that need not imply a total independence in re from one another. The above way of construing their inter-relationship allows for conceptual dependence on a logical basis with greater fidelity to the epistemological basis for that dependence than substratum theory offers.

In conclusion, the definition of substance presented above allows for a way to conceive of substance that satisfies the demand for both irreducibility required by Aristotelians and other substance dualists and the epistemological grounding in perception sought by phenomenalists or materialists. It makes the two compatible by simply distinguishing conceptual independence from interdependence in re in a way that is logically valid and, arguably, sound. As a viable alternative, it argues against the need to construe substances as substrata.

An approach to Plato’s “dream theory” in the Theatetus through the Socratic dialogues

Plato’s late dialogue, the Theatetus explores the question, “what does it mean to know something?”.  This concern is not new within the Platonic dialogues.  In particular, the Phaedo, Meno, and Republic stand out as discussions of knowledge that anticipate in many ways the more explicit treatment given in the Theatetus. I believe that, despite what some recent criticism suggests, due consideration of  the matter will show that what is common to all these is not merely the question of knowledge in general, but the problem of separation or “chorismos”: the classic problem of how to arrive at a knowledge of unchanging truth on the basis of ever changing experience.

Despite the widespread recognition of separation as a common thread of the middle dialogues, the third section of the Theatetus, in which Plato gives his fullest account of knowledge, is often presented as a discussion that falls outside this continuity.  This is even more surprising in view of the fact that the theme of the third section, the so called “dream theory”, explores a possible definition of knowledge which is also explored in the last attempt at defining virtue in the Meno: the hypothesis that knowledge is not merely a true opinion but one with a logically consistent account or “logos”.

The reasons why this approach has not been taken are not far to seek.  Theatetus, Socrates’ partner in the dialogue, introduces the dream theory as something he remembers having heard “someone” suggest (T 201C); Socrates, in turn, says he has heard the theory in a “dream” that matches the one Theatetus describes (one involving knowledge as true opinion with a consistent account). (T 201 c-d)  These details about attribution complicate an attempt to find a source for the theory that follows, (to be discussed briefly further on) but some have proposed Antisthenes as the author.  Whatever the origin of the theory, I would like to contend that the discussion that follows is certainly in part Plato’s way of exploring his own problem of separation.  On another front, some have argued that separation cannot be a theme in the Theatetus (see for example Waterfield’s ‘essay’) especially since Plato has abandoned the theory of Forms in the Theatetus.  There is ample evidence to suggest that separation, as well as the theory of Forms do make an appearance in the Theatetus, this time not as doctrines Plato is espousing but as ones he is examining.  I believe that once this move is made and the dream theory is read in continuity with the earlier dialogues, a new pathway to thinking about the problem of separation opens up.  Moreover, I believe the most consistent reading of the dialogue will yield the result that Plato has not solved the problem, but merely opened it up with greater clarity than elsewhere in his corpus as a difficulty to be solved.

This new pathway will be introduced by a brief sketch of the genesis of the separation problem in the Meno and Phaedo, followed by a discussion of the specific way in which I believe the problem of separation arises in the dream theory.  Once the link is drawn between the earlier and later dialogues in this way it will be possible to see just how the discussion of the separation problem in the Theatetus is innovative.


Perhaps the best starting point to catch a glimpse of the problem of separation in its genesis in the early dialogues is Socrates’ discussion of his youthful hopes for philosophical insight.  Socrates, according to his autobiographical account in the Phaedo had, at first, been interested in the exploration of the natural world.  Specifically, at (96A) he lists three questions he sought to answer: why a thing comes to be, why it perishes, and the cause of its being or existence.  The tale Socrates tells can be looked upon as a trans-migration from seeking knowledge in relation to the first two types of question to a concern with discovering in the cause of existence the true basis of explanation of the former two.  This type of cause is, importantly, not to be understood as a cause of a thing’s coming-to-be, but rather as the cause of its Being: something that stands above the sorts of causes that are concerned with the generation and destruction of things.  Socrates calls this cause the “cause of causes” and describes it as that cause without which the causes of generation and destruction would not be causes.  This cause can clearly be identified with Aristotle’s final cause.  In the Phaedo it is related to “mind” and described as that which orders or arranges with a view to some end or good order (harmony may also be read into the context here) which is pre-established as that at which the processes of generation and destruction continually aim.

To understand such an end as a cause is to have that which explains those processes themselves.  Socrates sought the knowledge of such a cause in Anaxagoras’ discussion of “Mind”, but found him making “no use of Mind” but instead gaving materialistic explanations for natural processes, using “air”, “ether” and “water” (basic elements) as his basis for understanding the natural world.  Socrates great insight, according to the story, might be said to be the discovery of the notion of an ultimate explanation that stands above those concerned with the causes of coming-to-be and passing away.

Here one can see the formulation of a distinction that would reach a level of thematic importance for Plato in the Republic: one between things characterized as involving a process of becoming (the natural world which is continually in flux) and other objects of understanding that are characterized, by contrast, as simply “Being”.  In the Phaedo, Socrates marks the distinction as one between the visible and the invisible or purely intelligible. (see P 79D)  These latter may be discovered, according to Socrates’ autobiographical sketch, by turning away from sights and sounds and turning toward an engagement with words and/or discussion (logoi) instead.  Once this step is taken, true knowledge is conceived as involving a consistent account (logos) of what one is trying to explain.  Moreover, this type of knowledge will correspond to a realizable end that stands to the flux of particulars as an ordered and ordering principle of arrangement and harmony that, in turn, explains the observable processes of change.

These points may be taken as a sketch of a theory that can be called Socrates’ ideal, if not precisely his dream, of complete knowledge that was later championed by Plato especially in the Middle dialogues: the Meno, Phaedo, and the Republic.  It will be a kind of knowledge that relates ideal models of reality to the fluctuating reality of the everyday world and can promise true insight into that world as if one understood the divine “Mind” ordering nature itself.  It involves the ideal of a “stairway” that one can climb to reach a more “divine” perspective beginning from the more (inevitably) quotidian one that Socrates and Plato took to be the concern of non-philosophical thought.


As was hinted at, a basic element of this ideal theory is a “separation” between visibles and intelligibles.  In order to contemplate the sort of cause that is the ordering cause of things, one must seek a unified idea that stands above and apart from the particulars it is meant to explain.  Now, it would seem that one could always gather a unified idea from particulars by abstracting some feature from them, such as when one might abstract the notion of three-sidedness from many instances of triangle.  In this instance we would have a purely synthetic approach to ideas; one that relies upon epagoge or induction.  Yet, as is familiar from Euclidean geometry, the notion of one material triangle that would correspond to every particular is impossible: in order to truly abstract from particulars, one must arrive at an idea.

The primary reason Plato gives for a type of ontological separation corresponding to that found in euclidean geometry arises in the Phaedo, and involves thinking about the nature of opposites: firstly, in the context of the natural world, and next, in a logical context as dialectical opposites.  According to Socrates’ reasoning, in the natural world, a thing always comes to be from its opposite.  For example, heat comes into being out of what was formerly cold.  However, logical opposition never has this feature.  Logical opposites always simply are what they are.  They are, as Plato sometimes says, ‘pure’, in the sense that they are free from that which they are not.  It is very tempting to think of dialectical opposition in concrete terms for the purpose of illustration: ‘pure’ white, ideal white, because it is precisely what is not not-white, can have no intermixture within itself of what is not what it is.  One may think of these “realities” as if they were on a spectrum of being: on one end one can imagine pure white or the Form of white, while on the other end would be placed the not-white (its opposite).  In between, would be an area of intermediacy (a point that will be of central importance in what follows).  Two problems might be seen to arise in the natural world in connection with any attempt to identify a particular instance of white with its Form: in the first instance, there is the problem of identifying “white itself” with something known to the senses: what appears purely white at one time may appear different at different times to different people.  This is a problem of separation between appearances and reality.  Secondly, there is the matter of flux: according to the criterion enforced by dialectical scrutiny, what is purely white or white itself must be eternally so: its basic idea must not be mutable or subject to change, and as a consequence, it can never become its opposite. (Phaedo 103b).  One encounters these two bases of separation in the dialogues again and again.

What remains to be seen next in this connection is the way in which these elements of separation line up with what appears in the dream theory of the Theateus.  As was already mentioned in the introduction, my intention is to show that there is a continuity between the early and middle dialogues and the dream theory that appears in the Theatetus.  So let us now turn to the Theatetus itself.


What has given interpreters the greatest trouble in approaching the Theatetus is how to understand the elements Plato speaks of at 201e-202c.  As was said in the introduction, one basic problem has been the question of the attribution of the dream.  However interesting points of similarity may be drawn between the elements of the dream theory and Plato’s own understanding of the relationship between forms and particulars.  If we look to the text itself, the problem the interpreter faces may be one of underdetermination.  For example, even if Socrates did hear the theory somewhere else, does that necessarily exclude the possibility that Plato could have incorporated it into his own?  It seems that if some insight can be taken from such an approach it is worth exploring.

If we look to the description Socrates gives of the elements, they do not appear to be precisely the same as anything in Plato’s cosmos.  However, they do appear to fit very well with the understanding of particulars he develops in the Republic, and with the theme of separation mentioned earlier.  The way in which Being is, for Plato something simple and abstract was discussed above.  It will now be seen that there are parallels between Plato’s middle dialogue Forms and the elements dicussed here; but what is of ultimate importance are the differences.  There is a sense in which the elements of the Theatetus and Forms mirror one another; but there are important ways in which the elements fall short of the Forms.  

The elements appear to have a very minimal sort of being.  Indeed, from Plato’s description of them, it is difficult to see what being or non-being they have at all.  The important features mentioned are:

  1. Nothing can be attributed to them, including absolute being or non-being, or even phrases such as ‘itself’, ‘that’, ‘each’, ‘independent’, ‘this’, or anything else.
  2. They are attributes that ‘run around’ and get applied to everything, while they are different from what they are applied to.
  3. Since they only have names, it is impossible to give a rational account (logos) of them.
  4. They are that of which everything is made.
  5. Their names can be woven together to produce accounts that are intelligible even if the names by themselves are not (since an account is a weaving together of names).
  6. The physical elements can be woven together in the same way as their names.

The differences between the elements here and the Forms of the middle dialogues can now be drawn.  While each has a kind of simplicity, the description of elements goes further: nothing whatsoever can be attributed to them, whereas the Forms are usually described using terms such as “itself”, and “pure”.   Moreover, while the Forms explicitly have an absolute being, the elements here cannot be said either to be or not to be.  For all these reasons they are unknowable, whereas the Forms are described as the “intelligibles”.

Taking these points together, one kind of being found in Plato’s ontological schema applies especially well to the elements as presented: the intermediate being discussed above.  Intermediate being has to be understood within a framework of logical opposition if it is to be understood at all.  In fact, the whole set of attributes is hardly intelligible at all unless it is understood within this framework.  Ryle, for example, sought to understand the elements as logical simples; but this explanation seems to ignore the heavy ontological as well as logical slant of Socrates’ characterization.  It is clear from the points above that more than logical atoms are in view: there is indeed an attempt to describe a certain kind of being, and the way in which it may or may not be understood.  Moreover, these beings do not appear to fit entirely well with the characterization of them as material simples.  They certainly may be since they are “that of which everything is made”.  Yet the text is underdetermined as to the sense in which they make things up.  They are described as “attributes”: this opens the possibility that they are such things as would correspond to “red”, “green”, “5 feet tall”, etc. that make up all things, rather than the materialists’ atoms.  I believe that these considerations point to the sense of intermediate being discussed above as a possible way to understand all the points discussed above without making any definite commitments to the nature of the elements beyond the description given.

Now, here are some parallels that may be drawn between the characterisitics of the elements above and the “intermediates” in view:

  • From the perspective of dialectical opposition the intermediates are between being and non-being.  Hence they neither are nor are not.  If they lack these basic attributes, then it cannot be said that they possess any other characteristics (again, from the perspective of dialectical opposition, according to which a thing is either P or ~P, and P is defined as what is ~~P). (See Phaedo 103b)
  • The elements, like the intermediates, are things that fall short of a definite account, since they fall short of the kind of being the Forms themselves have. (Phaedo 72b-77a: note the way in which the discussion proceeds from Anaxagoras’ mixed cosmos of of things coming to be to the discussion of the Equal itself, and how this parallels Socrates’ discussion of Anaxagoras and his hopes for knowledge in the autobiographical section 96a and following).
  • The intermediates possess being (again from a dialectical perspective) only to the extent that they participate in the “reality” of the Forms themselves.  For example, snow is cold by participating in “cold”; but snow may become hot, in which case it loses its being as snow.  The name “cold” does not always apply to it, but is in a sense a borrowed name from that which is always “cold”.  Hence, just as above, an intermediate which is cold can be said to have its being by participation, and moreover its name by participation.  It has just this name to give it its reality, and does not even possess this reality absolutely, but only by participation. (see especially Phaedo 103e)
  • The intermediates have the character of attributes such as “hot” and “cold” that go into and out of bodies.  Hence, they could quite easily be said to be that of which everything is made in a sense that is both ontic (a thing really is hot or cold) and logical (a thing is referred as hot or cold when it has the proper characteristics).  (Phaedo 103c-d)
  • The same result follows with respect to the weaving together of names to form logoi (accounts, explanations, arguments, definitions).  In order to have a true account of something, it must be created from names that point to the reality of the thing in question. Indeed, it seems necessary that this should be the case if definitions can be drawn from division (such as those in the Sophist), and if it is to be possible to rise to the intelligible from the visible at all.  (see Phaedo 76d-e, where Socrates explicitly makes the latter point)

It remains now to show that not only something corresponding to the intermediates, but also something corresponding to the Forms is present in Plato’s discussion.  It is important to explore this aspect of separation since the presence of anything corresponding to the Forms in the Theatetus has been contested. (See Waterfield’s “Essay” pp. 239-246)  What I want to argue here is not that Plato is maintaining a theory of Forms corresponding to the middle dialogues, but, rather, that he is using the framework in the dream theory in order to evaluate the point of view of the middle dialogues.

The similarities to a separation framework are, in fact, ubiquitous.  At 187a, for example, Socrates mentions a function of the mind involved solely with things themselves.  Here there is not only a continuation of the theme of the separation of the visible and intelligible in terms of being, but also in terms of psychological faculties.  At 190b, he uses the framework of dialectical opposition invoked above where he speaks of the impossibility of imagining that what is beautiful is ugly, or that what is immoral is moral, or again that what is odd is even.  Here is the basis for separation precisely on the lines on the absolute Being of the Forms: a kind of being not subject to change into its opposite.  Furthermore, where Socrates proposes an intepretation of a syllable in the dream theory as a single identity without parts (Phaedo 204a (to be explained more fully further on)) this description corresponds best to the simplicity of the Forms.  When the characteristics of the ‘elements’  (as above) are compared these self-identical syllables, the result again invokes the classic separation framework of the middle dialogues.  Lastly, at Theatetus 205d, Socrates describes the same syllables as ‘single in form’.  It does not seem that either separation or the presence of Forms in the Theatetus can be dismissed out of hand.

Separation has been explored and developed as a theme that links the early and middle dialogues to the Theatetus.  The precise link that has been proposed is that between intermediate being and the elements on the one hand and an interpretation of the syllables (to be discussed further in what follows) as Forms on the other.  It remains to gather in fruits of this labor over the comparison, and to show just what new insight can be gleaned from this reading.  It will be shown that what the Theatetus advances over the earlier dialogues is further discussion of separation as a problem, rather than merely a feature of a complete middle-platonic theory of knowledge.  This occurs in the Theatetus as a problem for knowledge itself; one that is again familiar from the earlier dialogues, but explored in the later dialogues in greater depth.  The theory of knowledge presented in the middle dialogues is presented there as a viable epistemological schema.  However, just as the ideal emerged so did the questions that troubled it.  It will be the concern of the next section to explore these.


Much of what Plato writes concerning knowledge in the early and middle dialogues is concerned with developing criteria for knowledge.  For example, Socrates will often ask whether in the process of defining something, his interlocutor is giving an instance or example of what is to be defined or a definition that covers the whole of the cases concerned.  It is clear throughout these dialogues that there is a difference between the kinds of things that count as instances and those that count as unified ideas or accounts of instances.  These differences are specified and clarified in order to give us an idea of what we are seeking when we seek knowledge; when we are attempting, in other words, to grasp the ultimate Forms of things.  Such clarifications yield an understanding of separation as a matter of difference between visibles and intelligibles.

Separation does not arise in these dialogues as a structural problem to be overcome except in the case where the problem of the Meno is introduced.  Here it is asked, in effect, how one can know that one has arrived at one’s destination in seeking knowledge without prior knowledge of what one is seeking.  It seems that it cannot, and that one can only know that one has arrived at knowledge to the extent that one had prior knowledge of what one was seeking.  This necessary fore-knowledge could be present as the framework of a question that allows it to be answered effectively; or, it could be information contained in the premisses of an argument that allows one to proceed to a conclusion; but for the Socrates of the middle dialogues, who has the problem of arriving at a knowledge of the Forms in view, what is fore-known is something innate that needs to be accessed by a process of inquiry.  According to the theory, this knowledge was had by the soul before it entered the body.

Recollection theory functions as a way to unite the visibles and intelligibles of Plato’s epistemology.  If the Forms are so abstract as to be only identical to themselves (auto kath’ hauto), the question must arise as to how we get to know them if at all.  It would seem an unfortunate thing to develop a theory of knowledge only to find that knowledge within the theory was something unattainable.  This may explain the extravagance of the recollection theory of the Phaedo, with its questionable reliance upon the immortality of the soul to make it possible.  Recollection-knowledge arises as a matter of a sudden realization of a similarity, not among things in the visible world, but between things in the visible world and those in the intelligible world.  Such recollection requires innate knowledge.  This is a picture of radical separation, one that invokes the classical two-worlds view of the Phaedo.  What the Theatetus does most of all is challenge the basis for this type of separation.

The challenge is issued precisely through considering the terms of the proposed definition of knowledge.  Where Theatetus proposes that knowledge be definable not only as a true belief, but also as one with an explanation or logically consistent account, the terms of knowledge found in the “road to Larissa” analogy of the Meno are implicitly invoked.  The “road to Larissa” analogy is similar to the “problem of the Meno” (i.e. the problem of prior knowledge) discussed above, and differs only in that it supposes that if one is to be an ideal guide to a destination (as in the Meno problem) one must not arrive by accident, but with something that allows for repeated success: an account or explanation of how to get there (a logos).  Such an explanation is something an ideal guide should possess beforehand.  Thus, the framework for discussing prior knowledge is invoked along with the third definition of knowledge under discussion in the Theatetus.

The basic premisses of the dream theory are (a) that the criterion for knowledge will be a rational account (logos); hence, where no rational account can be given no knowledge is possible; and (b) that the individual primary elements (discussed above) of which everything is made cannot be explained, while the complexes that are composed out of them can.  This sets the stage for the test Socrates gives for the theory, where he takes letters to stand in the place of elements and syllables to stand as their complexes.  The grounds for separation are already present here, but the example does not yet include an analogue to the Forms.  This enters where two possibilities for understanding the syllables are invoked.  Understood (i) as a composite, the syllable SO (the first syllable of Socrates’ name) is a kind of set comprising the individual letters as parts; understood (ii) as a single unified idea, the Syllable has to thought of purely in terms of its idea, as something that comes into being only when the parts are brought together in the right way, and even then, as something greater than the sum of those parts, since it has attributes that the parts themselves to not possess individually.  It is in the latter case that an analogue to the Forms is put forward and the theory of Forms as presented in the middle dialogues is put to the test.

The first understanding of a syllable is perhaps the one more congenial to common sense.  Surely, it might be thought, a syllable can be understood as a composite of its letters.  But what motivates Socrates to (ii) is the realization that if knowledge is to be founded along the lines of (i), the elements themselves must be knowable; but according to the criterion proposed for knowledge in the dream theory section this will be impossible since they are (as above) simple entities without composition, whether in a logical or in an ontic sense.  The second possibility invoked in (ii) provides a different sort of foundation for knowledge: one found in a “unified idea” that has no foundation in the elements other than the possibility of its arising, and no actuality apart from its own being.  The difficulty with such a theory is that is supposes that such a unified idea cannot have parts.  Socrates might be seen to be driven to propose this view as an alternative by the terms of bivalence: if (i) takes a syllable to have parts and draws its major consequences from this, then (ii) must be opposed to (i) if it is to be a distinct alternative and not collapse back into (i).  Moreover, it should now be noticed the problem of separation is finally put forward as a problem for a theory of knowledge.  In the middle dialogues it was solved by the theory of recollection.  Finally, the text suggests that the two approaches are incompatible on the level of analysis and synthesis.  The model (ii) of a ‘one’ and ‘unified’ idea cannot be analyzed into any elements if it is truly sui-generis, self-identical, and without parts; on the other hand, if, as in the earlier dialogues synthesis (as in case i) is to be a part of the way in which we arrive at knowledge, some leap beyond the parts themselves must be required in order to arrive at knowledge: one must, the model suggests be able to catch a glimpse of something not present in the parts themselves; yet this is indeed a problem if, according to the definition proposed, we cannot know anything of the parts themselves.

Socrates’ claim in the Theatetus is that (ii) with its notion of a “whole” with a unified idea cannot but collapse back into (i) with its leading notion of a totality of parts.  This does pose a problem for separation as an initial outcome of the dialogue up to T-205, but rather may be seen to bring to light the way in which the whole dilemma collapses.  The dialogue suggests that wholes and totalities, must, at the end of the day, be inter-definable in some sense.  One cannot claim to have parts of anything if one maintains the notion of a whole in sense (ii) as a criterion for knowledge.  Undeniably, there are such things as wholes, such as notes that make up music scores and numbers that make up larger numbers.  It seems unreasonable to think that these do not contribute to an understanding of what they compose, whether that composite is understood as a totality after (i) or a whole according to (ii).

Thus, a path to knowledge is finally put forward at T 206ff.  Interestingly, it is a path to knowledge that was first mentioned in the Phaedo. (see P 96b)  His proposal is that we should turn our attention back to the order in which we do in fact learn things.  In the order of learning letters or musical notes, one had first to recognize and distinguish each letter and note before one could put them together into words or compositions.  Moreover, there is an new insistence, in keeping with the doctrine of the Phaedo, that, based upon these examples, one can indeed know the elements or our experience and that one can reliably draw inferences from them. (see T 206b) 

A question that arises is whether this new path is meant in earnest as a solution to the dilemma discussed above, or whether it is merely meant as a counter-example.  The latter seems to be more the case, due especially to the fact that Socrates’ next move is to discuss possible senses of logos as a way of maintaining the definition of knowledge as true belief with an account.  In other words, the upshot of the whole discussion seems to be that the counterexample is meant to defeat the whole premiss of the dilemma: in actual practice, we do in fact proceed from elements we in some sense know, to something we learn as a result.  This defeats the main assumption of the dilemma, that while we may know the composite, we cannot know the elements themselves.   


We must finally turn to the question of what may be drawn from this discussion of knowledge.  Plato does not himself draw any conclusions, and there is a temptation to think that the whole dialogue has a merely heuristic function; that is, that it is meant to help the reader draw conclusions more than to present them.  That conclusion would certainly not be foreign to the Platonic-Socratic sprit.  However, it has been proposed that there is both a continuity and a shift between Plato’s ideal of knowledge and the scrutiny it receives in the Theatetus.  It will now be brought out more explicitly what Plato seems to have learned, or perhaps, at least what he reveals about his own thought in this self-critical dialogue.  What seems needed to discover this shift in self reflection is the adoption of a broad perspective.  I believe that the difficulty Plato reveals in the Theatetus for his earlier theory is a problem of two methods that each seem to work independently but not in conjunction: the methods of analysis and synthesis on the one hand, and the method of dialectical opposition on the other. 

I would prefer to think of the problem that arises for Plato in terms of a visual metaphor involving horizontal planes and vertical lines.  I believe an ideal image for the perspective I have in mind would be a Mondrian painting. 

The horizontal lines would represent Plato’s dialetical researches into logical opposition (the opposition between P and ~P discussed above), while the vertical ones would relate to the method of synthesis or the relating together of the aspects of one’s experience, or epagoge (roughly, induction by abstraction in Plato’s case).   The places where the lines intersect would correspond to points of understanding in the process of developing a complete body of knowledge; points where experience (synthesis) meets logic (dialectical opposition).  Analysis or division would enter as a method whereby one could draw out the consequences of knowledge one already possesses, perhaps in the way one does when working out a crossword puzzle.   

The methods are meant to work in harmony in the early and middle dialogues to create a perfect science; one in which “things themselves” such as the ideas of the “equal itself”, or of “triangle itself” would, while abstract and separate, be places where one can “stand” as a knower in the stream of fluctuating appearances.  It was perhaps Plato’s assumption that, given the doctrine of recollection, one could be assured in taking such stands.  The goal of the entire ideal seems to be nothing less than the discovery not merely of a kind of knowledge that explains one’s experience, but one which, if it passes the test of dialectical opposition, stands to explain any experience.  

The difficulty Plato seems to have noticed is that even if, supposing one has been given an insight that appears to be a matter of recollection, the two methods do not quite work in harmony.  (ii) above illustrates this well.  Suppose that one has a unified idea of a syllable, one that is self-identical so that it has no parts and has nothing in common with anything else: how, then, does one know through analysis that it bears a necessary relationship to experience.  In the matter of letters and syllables, this point might seem overly contentious at first or perhaps like nothing more than a philosopher’s debate.  But if we take the analogy seriously, there is something to be gained from it.  One must perhaps remember that the analogy is meant to have a broader application, but consider what the analogy suggests: is there any ultimate reason why the syllable should sound a certain way based upon the way the letters sound?  One may press the point further: given that the Greeks understood many letters to be ‘soundless’ (e.g. mutes, sibilants, nasals, and continuants) one could argue that from the Greek perspective, this type of argument has even greater relevance.  To state the same point in a different way, can anything necessarily be deduced from the sound of the syllable to that of the letters?  Knowing the sound of the letters, like that of the syllables seems to be something one must at some point just know; one must be taught the sounds one identifies with the letters and syllables. 

This point brings us back, of course, to the theory of recollection.  The theory of recollection solves the above problem by positing a pre-existing knowledge that lies within us.  But as the analogy suggests, no experience can lead us infallibly to such knowledge and such knowledge has, as the analogy again suggests, an air of irresolution about it.  Thus, what the Theatetus reveals are the interstices, the gaps in the horizontal and vertical crossings that ultimately prevent the structure from being ultimately strong or sound.  But, moreover, the lines and planes analogy may be carried into the world of engineering to yield the perspective that while a microstructure may not be free of interstitial defects, it may yet be a strong and useful one for most purposes.  Moreover, if this was Plato’s conclusion regarding his earlier theory of knowledge, he can be taken to have anticipated to some extent later epistemological insights that had to await the passing of the middle ages and the waning of the hope of subsequent centuries for truly objective knowledge.  Finally, this perspective reveals just where that hope might be kept alive: in the sort of synthetic exploration and discovery found in Plato’s counterexample to his own theory.  Whether this method can yield ulitmately definitive oppositions, is, of course, an open question.    


Plato’s Theatetus translated with an essay by Robin Waterfield (Penguin: 1988).

Corford, F.M., Plato’s Theory of Knowledge, the Theatetus and the Sophist (Dover 2003).  Originally published in 1957 by the Liberal Arts Press.

Plato Five Dialogues, trans. G.M.A. Grube (Hackett: 1981).

Plato’s Republic, trans. G.M.A. Grube (Hackett: 1974).

The Theaetetus of Plato with a revised text and English notes, trans. Lewis Campbell (Arno press: 1973).  Contains Greek text and valuable notes.

On Aristotle’s to ti ên einai and its translation

Aristotle’s phrase, to ti ên einai, is generally understood as a formula for expressing the notion of “essence”.  A problem that has arisen for translators, interpreters, and readers is how to understand the original greek words in a way that makes sense to us today.  The difficulty arises simply from what many have thought to be the disjointedness of the literal translation, which runs, “the what it was to be,” or as some have rendered it, “the what it was being”.

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One prominent suggestion for how to deal with the phrase comes from the Aristotelian scholar, Joseph Owens. Owens argued that the “was” in the phrase should be understood not literally, but in terms of its imperfective aspect.  Thus ên (“was” above) would be read as connoting an action taking place in a “timeless present” (“was” in its imperfetive sense carries the idea of an action without a start or an end).  Thus, the translation Owens recommends emerges as “the what-IS-being” (here the ‘was’ becomes a timeless ‘is’).  Moreover, as might be expected in the context of his book “The doctrine of being in the Aristotelian metaphysics”, Owens builds metaphysical implications into the timelessness of the IS in the expression, saying that it points us to what “essentially, necessarily is” in a thing, apart from the “unintelligible matter…which is the principle of contingency and change” in a thing.  Many translators choose to simply gloss the phrase as “essence”; but Owens’ translation serves as an attempt to work through the language to uncover the thinking behind the literal meaning of the phrase.

Owens’ treatment is indeed useful in developing Aristotelian concepts that are latent in the language. Nevertheless, I believe that an older tradition which translates the phrase more in terms of its literal meaning, which leaves the “was” intact also reveals a great deal about the notion of essence that should not be cast aside.  In what follows, I would  like to point out that there are ways in which his view complements the one being the literal rendering offered here, but also that there are important ways in which it may lead a reader to conclusions that are unlikely to have been accurate.


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To take up the complementarity between the “was” and “IS” translations first, it is important to see that Owens’ “the what-IS-being” emphasizes an aspect of form that places it outside of time in a way that contrasts with “the contingency of matter and change, upon which time follows” (4).  In this precise sense of form, it coincides with an understanding of form not as present in things, but as ideally separate in a way that coincides with a more Platonic sense of “form.”  Needless to say, this is, as was hinted at in the opening a highly metaphysical sense of form.  There is, of course, a sense in which one can consider “form” as abstracted in thought from all matter in which case it becomes literally an idea or else a celestial object in Aristotle’s cosmos.  Such a conception would lead one to consider form as manifested in matter apart from matter, and in this sense it coincides with one of the principles of the natural world, as one of the senses of ousia (the one that coincides with entelecheia) outlined above.

What is lacking in this reading is that it seems to forget that the entelechy in view is equally an aspect of ousia as it is experienced in the world around us.  Several of Aristotle’s pronouncements on the proper methodological approach to the natural sciences point in this direction, and it is perhaps as clear in De Anima II.2 as anywhere.  At the beginning of II.2, at 413a9-16, Aristotle is concerned to go beyond the the facts gathered together in the initial, general treatment of the soul in De Anima II.1 to access the core, so to speak, of what makes it what it is.  In doing so, he will proceed from what is more evident to the senses (phaneroteron) to an explanation that is more intelligible and clear as a reasoned account (kata ton logon). (5)  What should be noticed is that in doing so, Aristotle is in search of a cause that will explain the presence of the phenomenal facts gathered in the first section.  That cause or reason will have two aspects: one mentioned immediately above that is purely intelligible and can be grasped in terms of its logos or account, and another that is present in the thing: an aspect emphasized in the present context where he says that the cause sought after must be phenomenally present in the subject under discussion (alla kai ten aitian enhuparchein kai emphainesthai).  These are the two familiar poles of Aristotle’s notion of understanding, his fundamental starting points of knowledge (logos and sense experience) which must be connected if any truly explanatory demonstration is to be possible.

Any account of “essence” for Aristotle must be consistent with these two aspects of the cause or reason that explains what a thing is.  Moreover, as one might have glimpsed, these two aspects can and should be related to the three-fold division of ousia Aristotle draws out explained above as entelecheia (actuality), dunamis (potentiality), and the composite of the two.  In searching for the cause of the observable phenomena associated with a thing, one is likewise in search of its underlying actuality, or, again, that which makes a thing what it is.  Owens’ account would have our understanding of essence limited to actuality apart from all potentiality or coming to be not only in terms of its logical, rational formula (cf. kata ton logon above)  but also in terms of its existence in a composite thing.  That this is in fact what Owens is up to can be seen most clearly where he writes that “The notion back of the imperfect therefore should be that of necessary Being….” and again where he says his treatment of to ti ên einai “implies that the form is the fundamental Being of the thing”. However, most decisively, Owens writes that due to timelessness of this “Being”, “the Greek imperfect cannot be taken here as denoting past time” since “It refers in this phrase to something still present, and applies equally well to the timeless separate Forms.” (6)

Now, interestingly, Owens arrives at a sense of the role of to ti ên einai in Aristotle’s researches into the natural world that is perfectly compatible with the three-fold analysis of ousia given above.  This can be seen where Owens presents matter, form, and the composite as possible answers to the socratic “what-is-it”  question and then relates to ti ên einai exclusively to the formal aspect of what a thing is (pp. 186-7).  Owens relates this type of “Being” not merely to the form of a thing but also attempts depict it to the formal cause of a thing in a way consistent with his earlier characterization saying that, “The form appears to be ’cause’ in the highest sense, and as such is the ‘Entity’ of the what-IS-Being of the thing to which it is the cause”.  (7)  It does not seem to occur to Owens that there is a discrepancy between (a) his fully separate “Being” and (b) the role to ti ên einai plays in relation to ousia as analyzed in terms of the natural world: such an ousia is not, as the example of his treatment of the soul makes clear, to be understood as an abstraction from things, but the being of things.  The formal causality that such a being brings to composite being is more in tune with being in time rather than “Being” construed as separate and timeless.  This is brought out explicitly where Aristotle, at 412a27 writes that the soul is the first entelechy (lit. being-at-its-goal) of a physical body potentially having life, supporting among other things, waking and sleep.  Such beings can come into and go out of being in the natural world; only as mental abstractions or when considered as necessary within a logically based ontological reconstruction of the cosmos do they have a necessary being.  Thus, it seems it must be concluded that however strange Aristotle’s formulation may initially seem, it would be misleading to characterize to ti ên einai as indicating a purely timeless, abstract Being in all contexts.


Photo by the author, Gem Lapin Beaucoup

The question presents itself, then, whether Owens’ understanding of to ti ên einai in the Metaphysics ought to be taken as peculiar to that context or whether it might be construed as a more architectonic way of treating the phrase than the more temporal interpretation of essence given by the traditional translation.  It follows from what has been argued above that, precisely as it has been formulated, Owens’ translation will not stand as a more architectonic way of understanding of the role of to ti ên einai.  This should be evident from the fact that it is not applicable without qualification to the context of natural science (the method announced in the De Anima being applicable to the natural sciences generally).  On the other hand, as alluded to above, there is a sense in which the metaphysical reading of to ti ên einai is compatible with a more everyday physical way of considering being.  What, then, is the proper way of conceiving the relation between entelectic being and Owens’ Being?

If there is a priority that may be given to the metaphysical sense, it will not be one that connotes a platonic sense of essential Being.  That sense does not apply generally, if at all to Aristotle’s researches in natural science.  It may apply to the immaterial heavenly bodies of an Aristotelian cosmos; but even in such a context, may we be said to be contemplating a kind of Being that is truly timeless?  Such beings would seem to require a separate realm if  taken to be entities in Aristotle’s sense.  Recall that the planets do have motion-in their revolutions. (8)  I propose that the proper sense that belongs to the metaphysical formulation should be construed as compatible with what is for Aristotle kata ton logon (cf section 2 above), which amounts to a way of seeing or considering reality mentally that is purely intelligible and that allows for contemplation.  This mode of apprehending the world contrasts with a phenomenologically based one that forms the ultimate starting point of investigation.

Thus, I believe the type of priority Owens’ formulation will bear is one that is compatible with the order of explanation or of demonstration when full understanding has been attained: that is, when experience is explained with consistency by a governing principle, reason, or cause; or, again, when the logical account we give of things has attained both internal coherence and external coherence with the phenomena it explains.  This is obviously a sense in which the form of a thing, considered as an arche of understanding may have a logical priority over the observable phenomena associated with it it is meant to explain.  But this priority is of an entirely different order than a more ontological one that considers ousia as a component of things in the natural world.  Nevertheless, despite the apparent incompatibility, there is a place within Aristotle’s metaphysics where the two orders merge: where ousia is identified in Metaphysics Book Z as the foundation of everyday being, and more especially, associated with the formal reality that is in things.

This is in fact, what I believe should provide the locus for a more architectonic understanding of to ti ên einai.  It is in the context of Z that to ti ên einai is identified with the formal nature that is in things as a metaphysical principle.  This is a metaphysical sense that is compatible with being in time as considered in the physical world.  It may be applied to Aristotle’s analogy involving an axe: things come to have particular being, to be individual substances of a certain type when they can also be said to have a certain entelechy that is compatible with the way such things are ordinarily described.  In the case of an axe, this ordinary description will involve its having a blade, and in a very everyday sense, just as a lump of iron will not be an axe until it has a blade, so a particular sort of body will not be living unless it has a soul, and so on for other cases in the natural world.  When things become what is compatible with the way we ordinarily describe them they are what we say they are; an account of their essence clarifies just what it is that unifies such descriptions and explains the natural phenomena before us.  Such an account is precisely what Aristotle intends by the phrase to ti ên einai which indicates what sort of attribute or attributes a thing must possess if it is to be a certain kind of thing.  This being stands as the fulfillment of what a thing was-to-be.


(1) See The Doctrine of Being in the Aristotelian Metaphysics, p. 181.

(2) See Philoponus’ Commentary on the De Anima, under the pages marked with the Bekker number corresponding to the text.

(3) Cf. the text of Aristotle’s de Anima, II.1, ll. 412a6ff.

(4) Owens esp. pp. 183-184.

(5) 413a12 of DA II.2.

(6) Owens, pp.184-185

(7) Owens, p. 188.

See Aristotle’s Metaphysics, V.13, 1020a29-33, where Aristotle relates time to space and movement


Owens, Joseph.  The Doctrine of Being in the Aristotelian Metaphysics (3rd ed.).  (Toronto: Pontifical Institute of Mediaeval Studies, 1978). 

Ioannis Philoponi in Aristotelis De anima libros commentaria / consilio et auctoritate Academiae Litterarum Regiae Borussicae ; edidit Michael Hayduck.  (Berolini: Typis et Impensis G. Reimeri, 1897).

Aristotle. de Anima (ed. W.D. Ross).  (Oxford: Clarendon Press, 1961).