Plato's Timaeus

TIMAEUS

by Plato

Translated by Benjamin Jowett

Section 4.

The astronomy of Plato is based on the two principles of the same and the
other, which God combined in the creation of the world. The soul, which is
compounded of the same, the other, and the essence, is diffused from the
centre to the circumference of the heavens. We speak of a soul of the
universe; but more truly regarded, the universe of the Timaeus is a soul,
governed by mind, and holding in solution a residuum of matter or evil,
which the author of the world is unable to expel, and of which Plato cannot
tell us the origin. The creation, in Plato's sense, is really the creation
of order; and the first step in giving order is the division of the heavens
into an inner and outer circle of the other and the same, of the divisible
and the indivisible, answering to the two spheres, of the planets and of
the world beyond them, all together moving around the earth, which is their
centre. To us there is a difficulty in apprehending how that which is at
rest can also be in motion, or that which is indivisible exist in space.
But the whole description is so ideal and imaginative, that we can hardly
venture to attribute to many of Plato's words in the Timaeus any more
meaning than to his mythical account of the heavens in the Republic and in
the Phaedrus. (Compare his denial of the 'blasphemous opinion' that there
are planets or wandering stars; all alike move in circles--Laws.) The
stars are the habitations of the souls of men, from which they come and to
which they return. In attributing to the fixed stars only the most perfect
motion--that which is on the same spot or circulating around the same--he
might perhaps have said that to 'the spectator of all time and all
existence,' to borrow once more his own grand expression, or viewed, in the
language of Spinoza, 'sub specie aeternitatis,' they were still at rest,
but appeared to move in order to teach men the periods of time. Although
absolutely in motion, they are relatively at rest; or we may conceive of
them as resting, while the space in which they are contained, or the whole
anima mundi, revolves.

The universe revolves around a centre once in twenty-four hours, but the
orbits of the fixed stars take a different direction from those of the
planets. The outer and the inner sphere cross one another and meet again
at a point opposite to that of their first contact; the first moving in a
circle from left to right along the side of a parallelogram which is
supposed to be inscribed in it, the second also moving in a circle along
the diagonal of the same parallelogram from right to left; or, in other
words, the first describing the path of the equator, the second, the path
of the ecliptic. The motion of the second is controlled by the first, and
hence the oblique line in which the planets are supposed to move becomes a
spiral. The motion of the same is said to be undivided, whereas the inner
motion is split into seven unequal orbits--the intervals between them being
in the ratio of two and three, three of either:--the Sun, moving in the
opposite direction to Mercury and Venus, but with equal swiftness; the
remaining four, Moon, Saturn, Mars, Jupiter, with unequal swiftness to the
former three and to one another. Thus arises the following progression:--
Moon 1, Sun 2, Venus 3, Mercury 4, Mars 8, Jupiter 9, Saturn 27. This
series of numbers is the compound of the two Pythagorean ratios, having the
same intervals, though not in the same order, as the mixture which was
originally divided in forming the soul of the world.

Plato was struck by the phenomenon of Mercury, Venus, and the Sun appearing
to overtake and be overtaken by one another. The true reason of this,
namely, that they lie within the circle of the earth's orbit, was unknown
to him, and the reason which he gives--that the two former move in an
opposite direction to the latter--is far from explaining the appearance of
them in the heavens. All the planets, including the sun, are carried round
in the daily motion of the circle of the fixed stars, and they have a
second or oblique motion which gives the explanation of the different
lengths of the sun's course in different parts of the earth. The fixed
stars have also two movements--a forward movement in their orbit which is
common to the whole circle; and a movement on the same spot around an axis,
which Plato calls the movement of thought about the same. In this latter
respect they are more perfect than the wandering stars, as Plato himself
terms them in the Timaeus, although in the Laws he condemns the appellation
as blasphemous.

The revolution of the world around earth, which is accomplished in a single
day and night, is described as being the most perfect or intelligent. Yet
Plato also speaks of an 'annus magnus' or cyclical year, in which periods
wonderful for their complexity are found to coincide in a perfect number,
i.e. a number which equals the sum of its factors, as 6 = 1 + 2 + 3. This,
although not literally contradictory, is in spirit irreconcileable with the
perfect revolution of twenty-four hours. The same remark may be applied to
the complexity of the appearances and occultations of the stars, which, if
the outer heaven is supposed to be moving around the centre once in twenty-
four hours, must be confined to the effects produced by the seven planets.
Plato seems to confuse the actual observation of the heavens with his
desire to find in them mathematical perfection. The same spirit is carried
yet further by him in the passage already quoted from the Laws, in which he
affirms their wanderings to be an appearance only, which a little knowledge
of mathematics would enable men to correct.

We have now to consider the much discussed question of the rotation or
immobility of the earth. Plato's doctrine on this subject is contained in
the following words:--'The earth, which is our nurse, compacted (OR
revolving) around the pole which is extended through the universe, he made
to be the guardian and artificer of night and day, first and eldest of gods
that are in the interior of heaven'. There is an unfortunate doubt in this
passage (1) about the meaning of the word (Greek), which is translated
either 'compacted' or 'revolving,' and is equally capable of both
explanations. A doubt (2) may also be raised as to whether the words
'artificer of day and night' are consistent with the mere passive causation
of them, produced by the immobility of the earth in the midst of the
circling universe. We must admit, further, (3) that Aristotle attributed
to Plato the doctrine of the rotation of the earth on its axis. On the
other hand it has been urged that if the earth goes round with the outer
heaven and sun in twenty-four hours, there is no way of accounting for the
alternation of day and night; since the equal motion of the earth and sun
would have the effect of absolute immobility. To which it may be replied
that Plato never says that the earth goes round with the outer heaven and
sun; although the whole question depends on the relation of earth and sun,
their movements are nowhere precisely described. But if we suppose, with
Mr. Grote, that the diurnal rotation of the earth on its axis and the
revolution of the sun and outer heaven precisely coincide, it would be
difficult to imagine that Plato was unaware of the consequence. For though
he was ignorant of many things which are familiar to us, and often confused
in his ideas where we have become clear, we have no right to attribute to
him a childish want of reasoning about very simple facts, or an inability
to understand the necessary and obvious deductions from geometrical figures
or movements. Of the causes of day and night the pre-Socratic
philosophers, and especially the Pythagoreans, gave various accounts, and
therefore the question can hardly be imagined to have escaped him. On the
other hand it may be urged that the further step, however simple and
obvious, is just what Plato often seems to be ignorant of, and that as
there is no limit to his insight, there is also no limit to the blindness
which sometimes obscures his intelligence (compare the construction of
solids out of surfaces in his account of the creation of the world, or the
attraction of similars to similars). Further, Mr. Grote supposes, not that
(Greek) means 'revolving,' or that this is the sense in which Aristotle
understood the word, but that the rotation of the earth is necessarily
implied in its adherence to the cosmical axis. But (a) if, as Mr Grote
assumes, Plato did not see that the rotation of the earth on its axis and
of the sun and outer heavens around the earth in equal times was
inconsistent with the alternation of day and night, neither need we suppose
that he would have seen the immobility of the earth to be inconsistent with
the rotation of the axis. And (b) what proof is there that the axis of the
world revolves at all? (c) The comparison of the two passages quoted by Mr
Grote (see his pamphlet on 'The Rotation of the Earth') from Aristotle De
Coelo, Book II (Greek) clearly shows, although this is a matter of minor
importance, that Aristotle, as Proclus and Simplicius supposed, understood
(Greek) in the Timaeus to mean 'revolving.' For the second passage, in
which motion on an axis is expressly mentioned, refers to the first, but
this would be unmeaning unless (Greek) in the first passage meant rotation
on an axis. (4) The immobility of the earth is more in accordance with
Plato's other writings than the opposite hypothesis. For in the Phaedo the
earth is described as the centre of the world, and is not said to be in
motion. In the Republic the pilgrims appear to be looking out from the
earth upon the motions of the heavenly bodies; in the Phaedrus, Hestia, who
remains immovable in the house of Zeus while the other gods go in
procession, is called the first and eldest of the gods, and is probably the
symbol of the earth. The silence of Plato in these and in some other
passages (Laws) in which he might be expected to speak of the rotation of
the earth, is more favourable to the doctrine of its immobility than to the
opposite. If he had meant to say that the earth revolves on its axis, he
would have said so in distinct words, and have explained the relation of
its movements to those of the other heavenly bodies. (5) The meaning of
the words 'artificer of day and night' is literally true according to
Plato's view. For the alternation of day and night is not produced by the
motion of the heavens alone, or by the immobility of the earth alone, but
by both together; and that which has the inherent force or energy to remain
at rest when all other bodies are moving, may be truly said to act, equally
with them. (6) We should not lay too much stress on Aristotle or the
writer De Caelo having adopted the other interpretation of the words,
although Alexander of Aphrodisias thinks that he could not have been
ignorant either of the doctrine of Plato or of the sense which he intended
to give to the word (Greek). For the citations of Plato in Aristotle are
frequently misinterpreted by him; and he seems hardly ever to have had in
his mind the connection in which they occur. In this instance the allusion
is very slight, and there is no reason to suppose that the diurnal
revolution of the heavens was present to his mind. Hence we need not
attribute to him the error from which we are defending Plato.

After weighing one against the other all these complicated probabilities,
the final conclusion at which we arrive is that there is nearly as much to
be said on the one side of the question as on the other, and that we are
not perfectly certain, whether, as Bockh and the majority of commentators,
ancient as well as modern, are inclined to believe, Plato thought that the
earth was at rest in the centre of the universe, or, as Aristotle and Mr.
Grote suppose, that it revolved on its axis. Whether we assume the earth
to be stationary in the centre of the universe, or to revolve with the
heavens, no explanation is given of the variation in the length of days and
nights at different times of the year. The relations of the earth and
heavens are so indistinct in the Timaeus and so figurative in the Phaedo,
Phaedrus and Republic, that we must give up the hope of ascertaining how
they were imagined by Plato, if he had any fixed or scientific conception
of them at all.