## 1. Overview of the Dialogue



The opening conversation (17a1-27d4) introduces the
characters--Socrates, Timaeus, Critias and Hermocrates--and
suggests that the latter three would contribute to a reply to
Socrates' speech allegedly given on the previous day, which
presented an ideal political arrangement strongly reminiscent of the
 *Republic*.[3]
 This reply would start with an account of the creation of the
universe down to the creation of human beings and, in a second step,
show an ideal society in motion. Critias is meant to provide the
second step with his account of a war between ancient Athens and
Atlantis, the beginning of which we find in Plato's
*Critias*, while Timaeus is meant to deal with the first step
in our dialogue. Timaeus begins the discourse (27d5-92c9) with a
prologue (27d5-29d6) in which he sets out the metaphysical
principles on which his account is based, introduces the figure of the
Craftsman and his eternal model, and provides a brief comment on the
status of the account he is about to provide. This prologue is
followed by the discourse proper, which is uninterrupted to the end of
the dialogue (29d7-92c9). The discourse unfolds in three main
stages: the first sets out the achievements of Intellect
(29d7-47e2), the second gives an account of the effects of
Necessity (47d3-69a5), and the third shows how Intellect and
Necessity cooperate in the production of the psychophysical
constitution of human beings (69a6-92c9).



The first of the main sections of the discourse explains the existence
of the universe and some of its most general features teleologically.
The universe exists and manifests goodness because it is the handiwork
of a supremely good, ungrudging Craftsman, who brought order to an
initially disorderly state of affairs. It is a living thing
(*zo[i]on*, also translatable as "animal"),
because it is better for it to possess intelligence than to lack it,
and the acquisition of intelligence requires the acquisition of soul.
It is complete, and thus it includes within itself all the species of
living things as its parts. It is unique, because its model is unique;
the uniqueness of the model follows from its completeness. The
world's body is composed of fire (for visibility) and earth (for
tangibility), but these so-called elements require the mediation of
air and water in a progression of proportion to bind them together
into a unified, concordant whole. The shape of the universe's
body--a sphere--and the characteristics it possesses or
lacks are all explained in terms of their various purposes. The
composition of the world's soul out of a harmonically
proportionate series of portions of a mixture of both divisible and
indivisible Sameness, Difference and Being, and the division of these
portions into two intersecting circles (called the circle of the Same
and of the Different) explain the cognitive powers of the soul in
relation to the different types of objects of cognition: those that
are and those that become. When joined with the world's body,
they also explain the cosmological organization of the universe. The
heavenly bodies are divine and move in their various orbits to serve
as markers of time: the fixed stars to mark a day/night, the moon to
mark the (lunar) month and the sun to mark the year. Time itself came
into being together with these celestial movements as an "image
of
 eternity."[4]
 Individual souls are made up of the residue (and an inferior grade)
of the soul stuff of the universe, and are eventually embodied in
physical bodies. This embodiment throws the previously regular motions
of the soul into confusion as the soul is subjected to the forceful
disturbances of internal bodily processes as well as the impact of
external bodies upon it, particularly in sense experience. These
disturbances gravely impair the soul's cognitive functioning;
only with appropriate nurture and education can its original motions
be reestablished and proper cognitive functioning be restored. The
body and its parts were designed to support that functioning, and
Timaeus takes the design of the eyes and the mechanics of vision as an
important case in point.



Timaeus prepares for the transition to the second main part of his
discourse by pointing out that while a causal story of the sort he has
been telling so far is indeed concerned with what is properly the
cause (*aitia*) of the universe's generation, that story
is not by itself sufficient and must extend to an account of
"contributing causes" (*sunaitiai* or
*summetraitiai*, 46c7, 46e6, 68e4-5) as well. The
discourse must provide an account of the various physical structures
that are necessary for and support the achievement of the purposes of
Intellect. The properties possessed by these various structures are
determined by their constitutions as a matter of
"Necessity," and it is not open to the Craftsman to change
or eliminate the properties of these structures. The properties allow
(or disallow) certain processes desirable to the Craftsman, and to the
extent that Intellect achieves its desiderata, it succeeds in
"persuading" Necessity (48a2-5). It is the role of
the second major part of the discourse to set forth these contributing
causes.



The second main section begins with the introduction of the
receptacle, a "third kind" alongside the familiar
paradigmatic forms and the generated images of the forms
(49a1-4, 52a8, d2-4). The receptacle has been seen as
serving either as material substratum or as some form of space or as
combining both roles. Timaeus' account of the receptacle
presents several interpretive difficulties, some of which will be
discussed below. In the "pre-cosmic" state (the state
"prior to" the intervention of the Craftsman) the
receptacle is subject to erratic and disorderly motions, and moves its
contents in turn. Its contents are mere "traces"
(*ichne*, 53b2) of the subsequently articulated four
"kinds" (the so-called "elements"): fire, air, water and earth. Each
of these four kinds is made up of geometrical bodies--fire of
tetrahedra, air of octahedra, water of icosahedra, and earth of cubes.
The Craftsman begins by constructing these four regular solids as the
primary corpuscles of each of the four kinds. These solids have faces
that are made up (ultimately) of two types of right-angled
triangles--the half-equilateral and the isosceles--and it is
these triangles that are the "simples" of the physics of
the dialogue. Because their triangles are similar (half-equilateral),
only corpuscles of fire, air and water may be transformed into one
another; while corpuscles of earth are made up of isosceles triangles
and are thus excluded from such transformations. Each of the four
kinds has properties that are determined by the constitution of their
respective corpuscles, and these properties in turn determine how the
particles act upon and react to one another. These actions and
reactions are ongoing and perpetuate a state of non-uniformity which
itself is a necessary condition for motion, i.e., the continuation of
the interactions. Although each of the four kinds has a tendency to
move toward its own region of space, their being squeezed together in
a spherical universe without any gaps leads to the inevitable
transformations that occur when their various corpuscles cut or crush
one another. Thus it is assured that these migrations are never
completed in the sense that there would be a complete separation of
the four elements into separate regions. The account proceeds to
explain the various varieties of each of the four kinds, and the
sensible properties that they and their compounds manifest. An account
of sensible properties calls for a preliminary account of sensation
(including pleasure and pain), and it is with that preliminary account
that this section of the discourse concludes.



The third main section of the discourse--about the cooperation of
Intellect with Necessity--focuses primarily on the psychophysical
construction of the human being. While the Craftsman has created the
individual souls, he delegates the creation of the human bodies to the
lesser, created gods. As individual immortal (and rational) souls are
embodied in mortal bodies, the embodiment requires the further
creation of the "mortal" parts of the soul--the
spirited and appetitive parts, familiar from the *Republic* and
the *Phaedrus*. These parts are assigned their respective
locations in the body: the immortal and rational soul in the head, and
the two parts of the mortal soul in the trunk: the spirited part in
the chest (nearer to the head) and the appetitive part in the belly.
The various organs in the trunk--the lungs and heart in the chest
and the liver in the belly--support the functions of their
resident soul parts. The account proceeds to describe the formation of
the various bodily parts, setting out in each case the purpose of the
part in question and showing how its construction (out of the
appropriately selected materials) serves that purpose. The purpose is
prescribed by Intellect, and the properties of the
materials--selected because their properties render them
compliant to Intellect's purposes--are the consequences
(and thus contributions) of Necessity. For the most part, Necessity
serves the purposes of Intellect well, but this is not always the
case. A notable example of them coming apart is the covering around
the brain. That covering needs to be massive to provide maximal
protection, but that very massiveness would impede sensation, and so a
preferential choice must be made between the conflicting demands. Such
occasional cases of resistance by Necessity to the
"persuasion" of Intellect limit the degree of excellence
the created world can attain. Timaeus' discourse moves on with
an account of the mechanisms of respiration and digestion, and a
classification and etiological discussion of various diseases of both
body and soul. This is preparatory to an exhortation to properly
exercise both the soul and the body to recover or maintain physical
and psychic well being. The well being of the soul in particular is
emphasized: it is through realigning the motions of our souls with
those of the universe at large that we achieve our goal of living
virtuously and happily. The discourse concludes with an account of the
generation of women and non-human animals.


## 2. An Interpretive Question



Ever since Aristotle rejected the cosmology of the *Timaeus* on
the ground that it required not just a beginning of the universe in
time, but a beginning of time itself (*Physics*251b14-26), defenders of the dialogue--perhaps wishing
to neutralize Aristotle's critique while conceding that the
assumption of a beginning of time is problematic--have claimed
that the creation story is not to be read literally, but
 metaphorically.[5]
 This metaphorical reading of the dialogue became the prevailing
(though not exclusive) view among Platonists, from the Old Academy of
Plato's immediate successors to Plotinus (third cent. CE). The
question of how literally the creation story is to be interpreted
remains an intriguing one that continues to interest (and divide)
scholars to this day: if we follow the metaphorical interpretation, we
will read the account not as a process by which an intelligent
Craftsman put the world together at some time in the past, but as a
statement of the principles that underlie the universe at all times of
its existence. Key questions raised by this issue include the
following: (1) Is Intellect (personified by the Craftsman) literally
an intelligent agent of some sort, an entity that is ontologically
distinct from both the model and its copy, or can the Craftsman be
identified with some aspect of either the copy or the model--the
world soul, for example, or one or other of the forms--and thus
be reducible to something else? (On this question, see more below,
under "Teleology.") (2) How do we understand the relation
of the "pre-cosmic" state of the universe to its finished
state? The account posits that pre-cosmic state "before"
the creative process by which the ordered universe comes into being.
But if there is no time apart from the measured celestial motions, how
is that "before" to be understood? (3) If the creation
story is read literally, is it consistent with Plato's views on
related subjects set forth in other dialogues?
 [6]


## 3. Relation of the *Timaeus* to other Platonic Dialogues



The question of the place of the *Timaeus* relative to the
other dialogues has given rise to an acrimonious but nevertheless
fruitful debate, with far-ranging implications for our assessment of
Plato's philosophy. In 1953, G. E. L. Owen published a
provocative article that challenged the orthodox view of the
*Timaeus* as a work written during Plato's so called
"late" period, and argued that it should be regarded as a
middle dialogue instead, composed prior to the *Theaetetus* and
the *Parmenides*. Owen claimed to see in the *Timaeus* a
reassertion of several metaphysical views familiar from the
*Republic* but (on the reading proposed by Owen) subsequently
exposed for refutation in these two dialogues, both of which on the
orthodox view precede the *Timaeus*. The orthodox view was
based on long-standing tradition, but had been confirmed by the
stylometric studies of Plato's writings undertaken by late
nineteenth- and early twentieth-century philologists. Owen called into
question the assumptions and the results of these studies. Four years
later Owen's criticism of stylometry, as well as his
interpretation of the relevant arguments in the *Theaetetus*
and the *Parmenides*, were in turn vigorously if not
rancorously disputed by H. F. Cherniss in defense of the traditional
view (Cherniss 1965, 1977). This debate between these two scholars of
renown whose approaches to the study of Plato's dialogues were
so markedly different did much to bring a new level of acuity to the
analysis of Platonic texts. Over time the orthodox view appears to
have held its own. Both a more nuanced examination of the texts and
more recent computer-assisted stylometric studies have done much to
reinforce
 it.[7]



The opening of the *Timaeus*, depicting it as a sequel to a
conversation about the ideal city-state that resembles the
*kallipolis* of the *Republic* in important points,
connects the project announced in the *Timaeus* to the
*Republic*. This opening also presents the *Critias* as
a sequel to the *Timaeus*. And Socrates' request in the
*Phaedo* to provide teleological causes for the explanation of
the world, instead of the material causes employed in the cosmologies
of the Presocratics (97b-99b), is answered by *Timaeus*'
account of the rational cause of the universe (the *Timaeus*,
however, points out that the material causes of the *Phaedo*
also have to be considered in order to explain the perceptible world).



## 4. The Status of the Account



In his prefatory remarks Timaeus describes the account he is about to
give as a "likely account" (*eikos logos*) or
"likely story" (*eikos
 muthos*).[8]
 The description is a play on words: the subject of the account is
itself an "image" (*eikon*) and, Timaeus
avers, "the accounts we give of things [should] have the same
character as the subjects they set forth" (29b3-5).
Fashioned after an unchanging and eternal model--a possible
subject of a definitive and exact account--the universe as a
thing that becomes is shifting and unstable, and hence any account
given of it will be similarly lacking in complete accuracy and
consistency (29c4-7). This may be read as lowering our
expectations--the account is no more than likely. At the same
time, Timaeus says he will strive to give an account that is "no
less likely than anyone else's" (or "any other
[account]") (29c7-8) and, while the account cannot be
grasped by understanding (*nous*, 29b6--the faculty for
apprehending unchanging truths), it nevertheless merits our
"belief" (*pistis*, 29c3) and fulfills certain
standards. As Timaeus' account proceeds, we are frequently
reminded of its "likely"
 character,[9]
 and both the negative and positive connotations of that
characterization should be kept in mind.



The account, then, is presented as reasonable, thus meriting our
belief, but neither definitive nor complete (cf. 68b6-8), and
thus open to possible revision (cf. 54b1-2, 55d4-6). A
definitive account of these matters eludes humans (29d1) and is
available only to a god "and those human beings dear to
him"
 (53d4-7).[10]
 It has sometimes been argued that the qualification of the account as
"merely likely" supports a metaphorical reading of the
cosmology. This, however, is a mistake; it is not easy to see how the
distinction between an exact and definitive versus a reliable but
revisable account maps on to the distinction between a literal versus
a metaphorical account. The contrast should rather be seen as one
between apodeictic certainty (about intelligible matters) and
 plausibility[11]
 (about empirical matters). To the extent that the subject of the
account is a thing that becomes rather than a thing that is, as well
as a thing that is perceptible rather than a thing that is
intelligible, the account will be no more than likely. To the extent
that it is beautiful and ordered, modeled after a perfect reality and
fashioned by a most excellent maker, the account will be no less than
likely.


## 5. Being and Becoming



The account Timaeus gives of the generation of the universe is from
the outset based on metaphysical and epistemological principles
familiar from the dialogues of Plato's middle period,
particularly the *Republic*. Introducing the subject of his
discourse, Timaeus posits a distinction between *what always is and
never becomes* and *what becomes and never is*
(27d5-28a1). He goes on to connect each with its familiar
epistemological correlate (28a1-4): the former is grasped by
understanding (*noesis*) involving a reasoned account
(*logos*), and the latter by opinion (*doxa*), which
involves unreasoning sense perception (*aesthesis
alogos*). Although Timaeus does not here name the types of entity
that satisfy these descriptions, the reader familiar with the
*Republic* will call to mind the distinction between forms and
sensibles (518c, 534a). The role of *what is* as the model
after which the Craftsman designs and constructs the universe (29a)
recalls the role of the forms as models for the philosopher-rulers to
imitate in exercising their statecraft (*Rep*.
500b-501c). It is not until much later in Timaeus'
discourse (51b7-e6) that forms are mentioned for the first time,
and their existence is argued for on the basis of the distinction
(itself supported by argument) between understanding and (true)
opinion. And the identification of *what becomes* with
sensibles (in this case the universe as an object of sense) is readily
made at 28b7-c2 (see 5. in the argument below).



Timaeus' opening question ("What is that which always
*is* and never *becomes*...?") can be read
extensionally ("What entity or entities are such that they
always *are* and never *become...*?") or
intensionally ("What is it for some entity always to *be*
and never to *become...*?"). If read in the former
way, the answer will be "forms" or "a form."
If read in the latter way, the question is answered immediately in the
text  and hence this reading seems preferable : always to be is
to be intelligible and unchanging.



The metaphysical being-becoming distinction and its epistemological
correlate are put to work in an argument that establishes the
framework for the cosmology to follow. The conclusion of that argument
is that the universe is a work of craft, produced by a supremely good
Craftsman in imitation of an eternal model. The reasoning may be
represented as follows:


1. Some things always are, without ever becoming (27d6).
2. Some things become, without ever being (27d6-28a1).
3. If and only if a thing always is, then it is grasped by
understanding, involving a rational account (28a1-2).
4. If and only if a thing becomes, then it is grasped by opinion,
involving unreasoning sense perception
 (28a2-3).[12]
5. The universe is a thing that has become (28b7; from 5a-c,
and 4).
	1. The universe is visible, tangible and possesses a body
	(28b7-8).
	2. If a thing is visible, tangible and possesses a body, then it is
	perceptible (28b8).
	3. If a thing is perceptible, then it has become (28c1-2; also
	entailed by 4).
6. Anything that becomes is caused to become by something
(28a4-6, c2-3).
7. The universe has been caused to become by something (from 5 and
6).
8. The cause of the universe is a Craftsman, who fashioned the
universe after a model (28a6 ff., c3 ff.; apparently from 7, but see
below).
9. The model of the universe is something that always is
(29a4-5; from 9a-9e).
	1. Either the model of the universe is something that always is or
	something that has become (28a5-29a2, also implied at
	28a6-b2).
	2. If the universe is beautiful and the Craftsman is good, then the
	model of the universe is something that always is (29a2-3).
	3. If the universe is not beautiful or the Craftsman is not good,
	then the model of the universe is something that has become
	(29a3-5).
	4. The universe is supremely beautiful (29a5).
	5. The Craftsman is supremely good (29a6).
10. The universe is a work of craft, fashioned after an eternal model
(29a6-b1; from 8 and 9).



Given familiar Platonic doctrines and assumptions, the argument up to
the intermediate conclusion that the universe has a cause of its
becoming (7) presents no particular difficulties. But 7 by itself
gives only partial support to
 8.[13]
 Here it helps to anticipate 9d as a fundamental premise in
Timaeus' reasoning; it is not just the generation of any world,
but that of a supremely beautiful one that Timaeus' reasoning
here--and in fact throughout the discourse--attempts to
explain. That a world as beautiful as ours might be the effect of an
unintelligent cause is a possibility that Plato does not discuss.



Once the conclusion that the universe is teleologically structured is
settled, the explanatory methodology of the discourse proceeds
accordingly. The question that frames the inquiry is not the question:
What best explains this or that observed feature of the world? It is
rather the question: Given that the world as a whole is the best
possible one within the constraints of becoming and of Necessity, what
sorts of features should we expect the world to have? This question
invites a priori answers, and Timaeus' arguments about the most
general features of the universe as a whole (for example, why it
exists, why it is alive and intelligent, why it is unique, why it is
shaped and composed as it is) are derived wholly a priori. The answers
to these questions are not open to empirical confirmation. But clearly
the inquiry is also constrained by features of the universe that are
actually observed, and this gives rise, secondly, to questions about
the good purposes that are being served by these features (for
example, the motions of the heavenly bodies, the psychophysical
constitutions of human beings, etc.), and how the features in question
accomplish those purposes. For the most part there is a happy
coincidence between the features that are required (in answer to the
first question), and the features that are actually observed (in
answer to the second), and it is part of the genius of the discourse
that these are so well woven together. Occasionally, however, the
methodology leads to conclusions apparently at odds with
observation--for example, the exemption of earth from
inter-elemental transformation (see further under
"Physics"
 below).[14]



The model that serves the Craftsman is regularly named the
"Living Thing (Itself)," and this is either a form, or an
appropriately organized constellation of forms. It is the Ideal (or
better: Real) Universe; the object of what Plato had called
"real astronomy" (as opposed to empirical astronomy) in
the *Republic* (527d-531d, esp. 530a3). The Craftsman
does not--indeed logically cannot--copy by replicating the
Living Thing; his challenge rather lies in crafting an image of it
that is subject to the constraints of becoming: unlike the model, it
must be visible and tangible (28b7), hence three-dimensional
(solid--*stereoeide*, 32b1). This constraint in turn
requires the postulation of something three-dimensional *in
which* the created universe may subsist, what Timaeus initially
names the "receptacle (*hupodoche*) of all
becoming" (49a5-6) and subsequently calls
"space" (*chora*, 52a8, d3).



The imitative activity of the Craftsman, who forms the universe as an
imitation of an eternal model, is unlike that of a builder who
replicates a larger- or smaller-scale three-dimensional structure as
model, but like that of a builder who follows a set of instructions or
schematics. That set is the intelligible, non-material and non-spatial
model that prescribes the features of the structure to be built; it is
not a structure itself. It is a matter of debate whether Plato's
middle-period metaphysics included the view that forms were, or
exhibited, some grander, unalloyed version of some of the properties
exhibited by sensible objects. Arguably such a view (call it
"crude paradeigmatism") was refuted by the "Third
Man" argument of the *Parmenides* (132a). As invisible,
intangible, and non-spatial entities forms are excluded from
possessing properties that only visible, tangible and spatial object
may possess. Nevertheless, in so far as they are or exhibit
intelligible natures forms may, like a set of instructions or
schematics, serve as models to be "looked at" (28a7, 29a3)
by anyone who understands those natures and is in a position to
construct a world in accordance with them. (This view of the
Craftsman's imitative activity might by contrast be described as
"refined
 paradeigmatism."[15])


## 6. The Receptacle



Timaeus introduces the receptacle as a "third kind"
(*triton genos*, 48e4) alongside forms and their imitations. He
apologizes for the obscurity of the concept, and attempts to explicate
its role by means of a series of analogies: it is variously compared
to a lump of gold (50a4-b5), a mother that together with a
father produces offspring (50d2-4, 51a4-5), a plastic,
impressionable stuff (50c2-6, e7-51a1), and an ointment
that serves as a neutral base for various fragrances (50e5-8).
These images suggest that it is devoid of any characteristics in its
own right (except those formal characteristics necessary to its role,
such as malleability). The receptacle is posited as the solution to a
problem: none of the observable particulars persists as this or that
(for example as fire or water) over time. We observe the very thing
that is fire at one time becoming air, and subsequently becoming
water, etc., "transmitting their becoming to one another in a
cycle, so it seems" (49c6-7). Thus the thing that appears
as fire here and now is not fire in its own right: its fieriness is
only a temporary characterization of it. What, then, is that thing in
its own right? In a difficult and controversial passage Timaeus
proposes a
 solution:[16]
 In its own right it is (part of) a totally characterless subject that
temporarily in its various parts gets characterized in various ways.
This is the receptacle--an enduring substratum, neutral in itself
but temporarily taking on the various characterizations through traces
of the four elements in it. The observed particulars just are parts of
that receptacle so characterized (51b4-6).



The above analogies may be seen as suggesting that the receptacle is a
material substratum: as gold qua gold is the material substratum for
the various geometrical configurations it is shaped into, the ointment
base for the fragrances, or the impressionable stuff for the various
impressions, so the receptacle serves as the "stuff" that
gets characterized in various ways. But Timaeus does not use any
descriptive word that can suitably be translated as
"matter" or "material"; he does, however, use
the word, "space" (*chora*). And its function
of providing a "seat" (*hedra*, 52b1) reinforces
the conception that its role is to provide a spatial location for the
things that enter it and disappear from it (49e7-8,
50c4-5, 52a4-6).



There has been considerable discussion about whether the receptacle is
to be thought of as matter, or as space, and whether it is possible to
think of it coherently as having both of those roles. And there is
also ongoing disagreement about the nature of the entities that are
said to enter into and disappear from the receptacle. They are clearly
not forms (52a4). Some interpreters have suggested that these are
character types (or character tokens) derived from the forms, and that
these types (or tokens) are properly the form copies
(*mimemata*) that have a prominent place in the argument
for the receptacle (49c7-50a4). Whatever the merits of this
reading, the things the receptacle is said to "receive"
are "all the bodies (*somata*)" (50b6).
Bodies are three-dimensional entities, and this makes it likely that
it is the emergence and disappearance of the variously characterized
observable particulars as such, and not their properties (types or
tokens), that are mentioned in these passages (49e7-8,
50c4-5, 52a4-6). But the particular bodies have a
geometrical underpinning--the four "elements",
which are the building blocks of the physical world, are made up of
the so-called Platonic solids; and these solids, in turn, are made up
of two kinds of triangles (cf. below). 



The complete metaphysical scheme of the Timaeus that is summed up at
50c7-d4 and again at 52a1-b5 is thus as follows: (i) the
eternal and unchanging forms, the "model," or
"father"; (ii) the receptacle, or "mother,"
and (iii) the copies of the model or "offspring" of the
father and the mother. These three are the components of Plato's
analysis; they are not three ontologically distinct ingredients. The
receptacle is introduced not as a distinct entity newly superadded to
particulars and forms, but as a new and essential component in the
analysis of what it is to be a spatio-temporal particular. What is
missing from that analysis, however, is any mention of character types
or tokens, and while later philosophers might see a use for such
concepts in elucidating the metaphysical scheme of the
*Timaeus*, it is not clear that Plato himself makes any use of
them there.



The introduction of the receptacle is an important innovation in
Plato's metaphysics, and clearly a development that takes him
beyond the metaphysics of the middle
 dialogues*.*[17]
 Little attention was given in those dialogues to the question of what
it is to be a sensible particular (other than being something that
participates in forms), or what is required of particulars to be such
that forms may be exemplified in them. In order to be effective in
their role of exemplifying forms, particulars must possess certain
general characteristics qua particulars: they must be spatially
extended and spatially situated, and they must be constituted of some
indeterminate but determinable "stuff" that is subject to
determination by way of participating in forms. Although the
receptacle does not appear by name in any other of the later
dialogues, it clearly has affinities to the concept of the
*apeiron* (indefinite or indeterminate) of the metaphysical
scheme in the *Philebus.* It is impossible, however, to
determine the chronological relation between these two dialogues with
certainty (see note 7), and thus impossible to infer which of the two
schemes Plato might have thought to be the more definitive.


## 7. Teleology



Many commentators on the *Timaeus* have pointed out that the
teleological account set out in the *Timaeus* is the
fulfillment of a quest for teleological explanations related in the
*Phaedo* (see, e.g., Strange 1999). In that dialogue the
character Socrates describes his foray into causal questions in the
realm of natural science and recounts both his high expectations of
and disappointment with Anaxagoras' concept of Intellect
(*nous*) as providing the true cause of natural phenomena.
Socrates expected the use Anaxagoras made of Intellect to provide
teleological explanations; instead, Anaxagoras employed the concept to
provide the same sort of causal explanation--in terms of physical
interactions--that Socrates had found confusing. Continuing to
hope for teleological causal explanations but finding them elusive,
Socrates settles for a second best account: offering causal
explanations in terms of participation in Forms (*Phaedo* 99c6
ff.).



It is not entirely clear by what avenue of reasoning Plato found what
his character Socrates failed to find in the *Phaedo*, but it
is reasonable to assume that the role of the form of the Good,
introduced in the *Republic*, assisted in the discovery.
Although the character Socrates in that dialogue declines to offer an
account of the nature of the Good, it is not unreasonable to connect
that form, as some have done, with rational, mathematical
 order.[18]
 Such order as the expression of goodness is arguably for Plato the
ultimate metaphysical datum; forms other than the Good are good in so
far as they possess such intelligible order, and they do so perfectly.
Sensibles are good in so far as they participate in these forms,
though they fail to do so completely. What is left to be explained,
then, is how such order is manifested in the visible universe, however
imperfectly. The explanation offered in the *Timaeus* is that
order is not inherent in the spatio-material universe; it is imposed
by Intellect, as represented by the Craftsman.



While the figure of the Craftsman seems to be an anthropomorphic
representation of
 Intellect,[19]
 it remains to ask what the ontological status of Intellect is, in
relation to the division between being and becoming--a
distinction that appears to be exhaustive. Some interpreters, relying
on Timaeus' claim (at 30b3) that intellect cannot become present
to anything apart from soul, have argued that Intellect is (part of)
the world's
 soul.[20]
 This cannot be correct: like the rest of becoming, the world's
soul is a product of the Craftsman, and hence neither it nor anything
else on the side of becoming can be identified with Intellect.
Alternatively, either Intellect is a form, or the distinction between
being and becoming is not exhaustive. Some have argued that Intellect
is to be identified with the entire realm of
 forms,[21]
 or the form of the
 Good,[22]
 while others, understanding "*nous*" to name a
virtue, have opted for the form of Intelligence (a substance in virtue
of its status as a
 form).[23]
 More recently, it has been suggested that the figure of the Craftsman
is a personification of
 craftsmanship.[24]
 None of these accounts seem adequate either: if Intellect were a form
of any kind, it would be an intelligible object, not a subject that
possesses cognition and efficient causal
 agency.[25]
 Intellect, then, cannot be placed either on the side of being or on
that of becoming, and that dichotomy is thus not
 exhaustive.[26]
 It is reasonable to conclude that Intellect is a *sui generis*
substance that transcends the metaphysical dichotomy of being and
becoming--possibly not unlike the Abrahamic conception of
 God.[27]



The teleology of the *Timaeus* may be usefully compared to that
of Aristotle's philosophy of nature. What is immediately
striking in that comparison is the absence from Aristotle's
natural philosophy of a purposive, designing causal agent that
transcends nature. Aristotelian final causes in the formation of
organisms and the structures of the natural world are said to be
immanent in nature (i.e., the nature or "form" of the
organism or structure) itself: it is not a divine Craftsman but nature
itself that is said to act
 purposively.[28]
 Such an immanent teleology will not be an option for Plato.
Aristotle's teleology is local, with no more than a few hints at
a global level : while it makes sense to ask Aristotle for a
teleological explanation of this or that feature of the natural world,
it makes little sense to ask him for a teleological explanation of the
world as a whole. Moreover, for Aristotle the development of an
individual member of a species is determined by the form it has
inherited from its (male) parent: the goal of the developing
individual is to fully actualize that form. For Plato the primeval
chaotic stuff of the universe has no inherent preexisting form that
governs some course of natural development toward the achievement of
some goal, and so the explanatory cause of its orderliness must be
external to any features that such stuff may possess.


## 8. Physics



While the receptacle has an obvious metaphysical role in the
*Timaeus*, its primary role after its introduction is in the
physical theory of the dialogue. The argument from 47e3 to 52d4
prepares the ground for both the spatial matrix in which to situate,
and the material substratum from which to constitute, the universe
that he will fashion after its eternal model. The fashioning, however,
is the process of bringing order to what was, prior to and apart from
the Craftsman's intervention, a thoroughly disorderly state of
affairs, and so the physical account begins with a description of that
disorderly, "god-forsaken" (53b3-4) initial
state.



In that state, dramatically described at 52d4-53c3, the filled
space that is the receptacle undergoes constant, erratic motion: it is
subject to forces (*dunameis*, 52e2) that are dissimilar to and
out of balance with each other, and thus, as each spastic movement
produces its chain of spastic reactions, it is perpetually unstable
(52e1-5). These motions may accidentally produce manifestations
that to a would-be observer look like fire or any of the so-called
four elements, or "kinds" (*gene*). Timaeus
calls these manifestations "traces" (53b2) of the four
kinds, and states that even as inarticulate traces, they tended to
behave in the ways in which the subsequently articulated kinds would
come to behave by necessity: each trace type would gather to its own
region, with the heavier to one region and the lighter to another.
These migrations are the effect of the ceaseless agitation of the
receptacle, which acts like a "winnowing sieve" (52e6),
separating the heavy from the light. The result is a pre-cosmic
inchoate stratification of these traces, which anticipates the
(perpetually incomplete, 58a2-c4) stratification of the finished
universe.



In accordance with the requirements for the construction of the body
of the universe previously set out at 31b4-32c4, the Craftsman
begins by fashioning each of the four kinds "to be as perfect
and excellent as possible..." (53b5-6). He selects as
the basic corpuscles (*somata*, "bodies")
four of the five regular solids: the tetrahedron for fire, the
octahedron for air, the icosahedron for water, and the cube for earth.
(The remaining regular solid, the dodecahedron, is "used for the
universe as a whole," [55c4-6], since it approaches most
nearly the shape of a sphere.) The faces of the first three of these
are composed of equilateral triangles, and each face is itself
composed of six elemental (scalene) half equilateral right-angled
triangles, whose sides are in a proportion of 1:[?]3:2. Timaeus
does not say why each face is composed of six such triangles, when in
fact two, joined at the longer of the two sides that contain the right
angle, will more simply constitute an equilateral triangle. The faces
of the cube are squares composed of four elemental isosceles
right-angled triangles and again, it is not clear why four should be
preferred to two. Given that every right-angled triangle is infinitely
divisible into two triangles of it own type (by dropping a
perpendicular from the right-angle vertex to the hypotenuse, the
resulting two smaller right triangles are both similar to the original
triangle) the equilateral or square faces of the solids and thus the
stereometric solids themselves have no minimal size. Possibly, then,
the choice of six component triangles for the equilateral and four for
the square is intended to prevent the solid particles from becoming
vanishingly
 small.[29]



Since each of the first three of the regular solids has equilateral
faces, it is possible for any fire, air or water corpuscles to come
apart in their interactions--they cut or crush each
other--and their faces be reconstituted into corpuscles of one of
the two other sorts, depending on the numbers of faces of the basic
corpuscles involved. For example, two fire corpuscles could be
transformed into a single air corpuscle, or one air corpuscle into two
fire corpuscles, given that the tetrahedron has four faces and the
octahedron eight (other examples are given at 56d6-e7). In this
way Timaeus explains the intertransformation that can occur among
fire, air and water. On the other hand, while the faces of the cube
particles may also come apart, they can only be reconstituted as cubes
since they are based on isosceles right-angled triangles; and so earth
undergoes no intertransformation with the other
 three.[30]
 Having established the construction and interaction of the basic
particles, Timaeus continues the physical account of the discourse
with a series of applications: differences among varieties of each of
the primary bodies are explained by differences in the sizes of the
constituent particles (some varieties consisting of particles of
different sizes), and compounds are distinguished by their
combinations of both different sorts and different sizes of particles.
These various arrangements explain the perceptible properties
possessed by the varieties of primary bodies and their compounds. An
object's particular arrangement of triangles produces a
particular kind of "disturbance" or
"experience" (*pathos*) in the perceiving subject,
so that the object is perceived as having this or that perceptible
property.



It is a fair question to ask how the physics of the discourse relates
to its metaphysics--for example, how the perceptible properties
of observable instances of fire (its brightness, lightness and heat,
let us say) relate to the form of Fire, an intelligible reality that
has no perceptible properties at all. The form of Fire is the
non-spatial, non-material, non-perceptible intelligible, eternal and
unchanging nature of fire that the Craftsman "imitates,"
and in so doing produces spatially extended, material, perceptible,
transient and variable instances of fire. Although we are not told
what it is about the nature of fire that requires observable instances
of it to have just these properties, it is presumably that knowledge
that guides the Craftsman to select and assign the four regular solids
as he does. Given that the nature of fire is such that any
"imitations" of it that appear in the Receptacle must be
perceptible as bright, light and hot, the type of solid body that best
supports these properties--the tetrahedron, it turns
out--should be assigned to fire. And so with the other three
kinds (see 55d7-56c7).


## 9. Ethics



Plato inherited from Socrates the conviction that knowledge of
goodness has a salvific effect upon human life. That knowledge
remained elusive to Socrates. As Plato continues the Socratic quest,
he expands the scope of the search beyond ethical matters. In the
*Phaedo*, as we saw earlier, the character Socrates expresses
the conviction that goodness is the true cause (*aitia*) of the
beneficent arrangement of the natural world, though the nature of
goodness continues to elude him as well. The causal supremacy of
goodness is recognized in the metaphysical and epistemological roles
assigned to the *Republic's* form of the Good, and it is
the understanding of that form that constitutes the culmination of the
education of the philosophical statesman, the paragon of the virtuous
and happy person. What remains to be articulated is a conception of
how cosmic goodness is manifested in the universe so that human beings
will recognize it, understand it, and emulate it in order that their
lives may become truly virtuous and
 happy.[31]



We saw above that in its dramatic context, the *Timaeus* is the
second of a series of three or possibly four (see *Critias*
108a-b) speeches exchanged by four or possibly five (see
*Timaeus* 17a) friends during one of the yearly Athenian
Panathenaic festivals. It is sandwiched between Socrates'
*Republic*-like speech, which is briefly summarized at the
beginning of the *Timaeus* (17c-19b), and Critias'
speech, the unfinished sequel to the
 *Timaeus*,[32]
 which was intended to recount and celebrate the great victory of
ancient, prehistoric Athens over the vast military might of
 Atlantis.[33]
 The stated thematic purpose of Timaeus' discourse is to provide
an account of human nature in the context of the nature of the
universe as a whole. Conjoined with Socrates' previous account
of education (a la *Republic*) this account will provide
the basis for Critias' forthcoming account of human virtue in
action, as displayed by the deeds of the ancient Athenians
 (27a7-b1).[34]
 If we take this stated purpose seriously, we will expect the entire
cosmological account to culminate in human psychology and ethics. And
that is indeed what we find.



In the passage that may fairly be taken as the climax of
Timaeus' discourse (90a2-d7), human beings are urged to
devote their utmost attention to the cultivation and preservation of
the well being of their immortal, rational souls. The well being of a
rational soul consists in its being well ordered (*eu
kekosmemenon*, 90c5), and so the goal of human life, given
the fact that the soul's revolutions were thrown off course
around the time of birth (43a6-44b1), is to realign
(*exorthounta*, 90d3) those revolutions with those of the
universe at large. Such realignment is achieved by a study of the
revolutions and harmonies of the universe and, once achieved, restores
the soul to its original condition and thereby brings to fulfillment
"that most excellent life offered to humankind by the gods, both
now and forevermore" (90d5-7).