Phaedo 72-76: we must have known the Forms before birth

And shall we affirm that there is such a thing as equality, not of wood with wood, or of stone with stone, but that, over and above this, there is equality in the abstract? --Affirm, yes, and swear to it, replied Simmias.

And do we know the nature of this abstract essence? --To be sure, he said.

And whence did we obtain this knowledge? Look at the matter in this way: Do not the same pieces of wood or stone appear at one time equal, and at another time unequal? --That is certain.

But are real equals ever unequal? or is the idea of equality ever inequality? --Never, Socrates.

What would you say of equal portions of wood and stone, or other materials? Are they equals in the same sense as absolute equality? or do they fall short of this in a measure? --Yes, he said, in a very great measure, too.

Now must we not agree that when I or anyone look at any object, and perceive that the object aims at being some other thing, but falls short of, and cannot attain to it, that he who makes this observation must have had prior knowledge of that to which, as he says, the other, although similar, was inferior? --Certainly.

And has not this been our case in the matter of equals and of absolute equality? --Precisely. Then we must have known absolute equality prior to the time when we first saw the material equals, and reflected that all these apparent equals aim at this absolute equality, but fall short of it? --That is true.

And it is from the senses, then, that is derived the knowledge that all sensible things aim at an idea of equality of which they fall short--is not that true? --Yes.

Then before we began to see or hear or perceive in any way, we must have had a knowledge of absolute equality, or we could not have referred to that the equals which are derived from the senses--for to that they all aspire, and of that they fall short? --That, Socrates, is certainly to be inferred.

And did we not see and hear and acquire our other senses as soon as we were born? --Certainly.

Then we must have acquired the knowledge of the ideal equal at some time prior to when we were born?  --True. ...

And therefore we must affirm that the soul existed before we were born, and possessed knowledge of the ideas...--Yes, Socrates; I am convinced that there is precisely the same necessity for the existence of the soul before birth, and of the essence or absolute idea of which you are speaking...

Phaedo 96-100: how Socrates came to the Theory of the Forms

At first, Socrates thought only in terms of the concepts and causes of nature

When I was young, Cebes, I had a prodigious desire to know that department of philosophy which is called Natural Science; this appeared to me to have lofty aims, as being the science which has to do with the causes of things, and which teaches why a thing is, and is created and destroyed; and I was always agitating myself with the consideration of such questions as these: Is the growth of animals the result of some decay which the hot and cold principle contracts, as some have said? Is the blood the element with which we think, or the air, or the fire? or perhaps nothing of this sort — but the brain may be the originating power of the perceptions of hearing and sight and smell, and memory and opinion may come from them, and science may be based on memory and opinion when no longer in motion, but at rest. And then I went on to examine the decay of them, and then to the things of heaven and earth, and at last I concluded that I was wholly incapable of these inquiries, as I will satisfactorily prove to you. For I was fascinated by them to such a degree that my eyes grew blind to things that I had seemed to myself, and also to others, to know quite well; and I forgot what I had before thought to be self-evident, that the growth of man is the result of eating and drinking; for when by the digestion of food flesh is added to flesh and bone to bone, and whenever there is an aggregation of congenial elements, the lesser bulk becomes larger and the small man greater. Was not that a reasonable notion? --Yes, said Cebes, I think so.

But then he discovered mathematics, which seemed to refer to non-physical entities

Well; but let me tell you something more. There was a time when I thought that I understood the meaning of greater and less pretty well; and when I saw a great man standing by a little one I fancied that one was taller than the other by a head; or one horse would appear to be greater than another horse: and still more clearly did I seem to perceive that ten is two more than eight, and that two cubits are more than one, because two is twice one. --And what is now your notion of such matters? said Cebes.

I should be far enough from imagining, he replied, that I knew the cause of any of them, indeed I should, for I cannot satisfy myself that when one is added to one, the one to which the addition is made becomes two, or that the two units added together make two by reason of the addition. For I cannot understand how, when separated from the other, each of them was one and not two, and now, when they are brought together, the mere juxtaposition of them can be the cause of their becoming two: nor can I understand how the division of one is the way to make two; for then a different cause would produce the same effect — as in the former instance the addition and juxtaposition of one to one was the cause of two, in this the separation and subtraction of one from the other would be the cause. Nor am I any longer satisfied that I understand the reason why one or anything else either is generated or destroyed or is at all, but I have in my mind some confused notion of another method, and can never admit this.

Then Socrates learned of Anaxagoras' theory of divinity, and of divine teleological causation (providence)

Then I heard someone who had a book of Anaxagoras, as he said, out of which he read that mind was the disposer and cause of all, and I was quite delighted at the notion of this, which appeared admirable, and I said to myself: If mind is the disposer, mind will dispose all for the best, and put each particular in the best place; and I argued that if anyone desired to find out the cause of the generation or destruction or existence of anything, he must find out what state of being or suffering or doing was best for that thing, and therefore a man had only to consider the best for himself and others, and then he would also know the worse, for that the same science comprised both. And I rejoiced to think that I had found in Anaxagoras a teacher of the causes of existence such as I desired, and I imagined that he would tell me first whether the earth is flat or round; and then he would further explain the cause and the necessity of this, and would teach me the nature of the best and show that this was best; and if he said that the earth was in the centre, he would explain that this position was the best, and I should be satisfied if this were shown to me, and not want any other sort of cause. And I thought that I would then go and ask him about the sun and moon and stars, and that he would explain to me their comparative swiftness, and their returnings and various states, and how their several affections, active and passive, were all for the best. For I could not imagine that when he spoke of mind as the disposer of them, he would give any other account of their being as they are, except that this was best; and I thought when he had explained to me in detail the cause of each and the cause of all, he would go on to explain to me what was best for each and what was best for all. I had hopes which I would not have sold for much, and I seized the books and read them as fast as I could in my eagerness to know the better and the worse.

Though he gave up on theology as a way of understanding, he agreed human beings did things for reasons, not just causes

What hopes I had formed, and how grievously was I disappointed! As I proceeded, I found my philosopher altogether forsaking mind or any other principle of order, but having recourse to air, and ether, and water, and other eccentricities. I might compare him to a person who began by maintaining generally that mind is the cause of the actions of Socrates, but who, when he endeavored to explain the causes of my several actions in detail, went on to show that I sit here because my body is made up of bones and muscles; and the bones, as he would say, are hard and have ligaments which divide them, and the muscles are elastic, and they cover the bones, which have also a covering or environment of flesh and skin which contains them; and as the bones are lifted at their joints by the contraction or relaxation of the muscles, I am able to bend my limbs, and this is why I am sitting here in a curved posture: that is what he would say, and he would have a similar explanation of my talking to you, which he would attribute to sound, and air, and hearing, and he would assign ten thousand other causes of the same sort, forgetting to mention the true cause, which is that the Athenians have thought fit to condemn me, and accordingly I have thought it better and more right to remain here and undergo my sentence; for I am inclined to think that these muscles and bones of mine would have gone off to Megara or Boeotia — by the dog of Egypt they would, if they had been guided only by their own idea of what was best, and if I had not chosen as the better and nobler part, instead of playing truant and running away, to undergo any punishment which the State inflicts. There is surely a strange confusion of causes and conditions in all this. It may be said, indeed, that without bones and muscles and the other parts of the body I cannot execute my purposes. But to say that I do as I do because of them, and that this is the way in which mind acts, and not from the choice of the best, is a very careless and idle mode of speaking. I wonder that they cannot distinguish the cause from the condition, which the many, feeling about in the dark, are always mistaking and misnaming. And thus one man makes a vortex all round and steadies the earth by the heaven; another gives the air as a support to the earth, which is a sort of broad trough. Any power which in disposing them as they are disposes them for the best never enters into their minds, nor do they imagine that there is any superhuman strength in that; they rather expect to find another Atlas of the world who is stronger and more everlasting and more containing than the good is, and are clearly of opinion that the obligatory and containing power of the good is as nothing; and yet this is the principle which I would fain learn if anyone would teach me. But as I have failed either to discover myself or to learn of anyone else, the nature of the best, I will exhibit to you, if you like, what I have found to be the second best mode of inquiring into the cause. --I should very much like to hear that, he replied.

This led him to inquire through human language and belief, which is how humans understand the world

Socrates proceeded: I thought that as I had failed in the contemplation of true existence, I ought to be careful that I did not lose the eye of my soul; as people may injure their bodily eye by observing and gazing on the sun during an eclipse, unless they take the precaution of only looking at the image reflected in the water, or in some similar medium. That occurred to me, and I was afraid that my soul might be blinded altogether if I looked at things with my eyes or tried by the help of the senses to apprehend them. And I thought that I had better have recourse to ideas, and seek in them the truth of existence. I dare say that the simile is not perfect — for I am very far from admitting that he who contemplates existence through the medium of ideas, sees them only "through a glass darkly," any more than he who sees them in their working and effects. However, this was the method which I adopted: I first assumed some principle which I judged to be the strongest, and then I affirmed as true whatever seemed to agree with this, whether relating to the cause or to anything else; and that which disagreed I regarded as untrue. But I should like to explain my meaning clearly, as I do not think that you understand me. --No, indeed, replied Cebes, not very well.

Phaedo 100-107: Socrates' Theory of Forms and Proof of the Immortality of the Soul

Socrates' "simple" Theory of Forms

There is nothing new, he said, in what I am about to tell you; but only what I have been always and everywhere repeating in the previous discussion and on other occasions: I want to show you the nature of that cause which has occupied my thoughts, and I shall have to go back to those familiar words which are in the mouth of everyone, and first of all assume that there is an absolute beauty and goodness and greatness, and the like; grant me this, and I hope to be able to show you the nature of the cause, and to prove the immortality of the soul. --Cebes said: I readily grant you this.

Well, he said, then I should like to know whether you agree with me in the next step; for I cannot help thinking that if there be anything beautiful other than absolute beauty, that can only be beautiful in as far as it partakes of absolute beauty — and this I should say of everything. Do you agree in this notion of the cause? --Yes, he said, I agree.

He proceeded: I know nothing and can understand nothing of any other of those wise causes which are alleged; and if a person says to me that the bloom of color, or form, or anything else of that sort is a source of beauty, I leave all that, which is only confusing to me, and simply and singly, and perhaps foolishly, hold and am assured in my own mind that nothing makes a thing be or be called beautiful but the presence and participation of beauty in whatever way or manner obtained; for as to the manner I am uncertain, but I stoutly contend that by beauty all beautiful things become beautiful. That appears to me to be the only safe answer that I can give, either to myself or to any other, and to that I cling, in the persuasion that I shall never be overthrown, and that I may safely answer to myself or any other that by beauty beautiful things become beautiful. Do you not agree to that? --Yes, I agree.

And that by greatness only great things become great and greater greater, and by smallness the less becomes less. --True.

Then if a person remarks that A is taller by a head than B, and B less by a head than A, you would refuse to admit this, and would stoutly contend that what you mean is only that the greater is greater by, and by reason of, greatness, and the less is less only by, or by reason of, smallness; and thus you would avoid the danger of saying that the greater is greater and the less by the measure of the head, which is the same in both, and would also avoid the monstrous absurdity of supposing that the greater man is greater by reason of the head, which is small. Would you not be afraid of that? --Indeed, I should, said Cebes, laughing.

In like manner you would be afraid to say that ten exceeded eight by, and by reason of, two; but would say by, and by reason of, number; or that two cubits exceed one cubit not by a half, but by magnitude? — that is what you would say, for there is the same danger in both cases. --Very true, he said.

Again, would you not be cautious of affirming that the addition of one to one, or the division of one, is the cause of two? And you would loudly asseverate that you know of no way in which anything comes into existence except by participation in its own proper essence, and consequently, as far as you know, the only cause of two is the participation in duality; that is the way to make two, and the participation in one is the way to make one. .... --What you say is most true, said Simmias and Cebes, both speaking at once.

This is your way of speaking; and yet when you say that Simmias is greater than Socrates and less than Phaedo, do you not predicate of Simmias both greatness and smallness? --Yes, I do.

But still you allow that Simmias does not really exceed Socrates, as the words may seem to imply, because he is Simmias, but by reason of the size which he has; just as Simmias does not exceed Socrates because he is Simmias, any more than because Socrates is Socrates, but because he has smallness when compared with the greatness of Simmias? --True.

And if Phaedo exceeds him in size, that is not because Phaedo is Phaedo, but because Phaedo has greatness relatively to Simmias, who is comparatively smaller? --That is true.

And therefore Simmias is said to be great, and is also said to be small, because he is in a mean between them, exceeding the smallness of the one by his greatness, and allowing the greatness of the other to exceed his smallness. He added, laughing, I am speaking like a book, but I believe that what I am now saying is true. --Simmias assented to this.

The reason why I say this is that I want you to agree with me in thinking, not only that absolute greatness will never be great and also small, but that greatness in us or in the concrete will never admit the small or admit of being exceeded: instead of this, one of two things will happen — either the greater will fly or retire before the opposite, which is the less, or at the advance of the less will cease to exist; but will not, if allowing or admitting smallness, be changed by that; even as I, having received and admitted smallness when compared with Simmias, remain just as I was, and am the same small person. And as the idea of greatness cannot condescend ever to be or become small, in like manner the smallness in us cannot be or become great; nor can any other opposite which remains the same ever be or become its own opposite, but either passes away or perishes in the change. --That, replied Cebes, is quite my notion.

An objection; Socrates' answer

One of the company, though I do not exactly remember which of them, on hearing this, said: By Heaven, is not this the direct contrary of what was admitted before — that out of the greater came the less and out of the less the greater, and that opposites are simply generated from opposites; whereas now this seems to be utterly denied.

Socrates inclined his head to the speaker and listened. I like your courage, he said, in reminding us of this. But you do not observe that there is a difference in the two cases. For then we were speaking of opposites in the concrete, and now of the essential opposite which, as is affirmed, neither in us nor in nature can ever be at variance with itself: then, my friend, we were speaking of things in which opposites are inherent and which are called after them, but now about the opposites which are inherent in them and which give their name to them; these essential opposites will never, as we maintain, admit of generation into or out of one another. At the same time, turning to Cebes, he said: Were you at all disconcerted, Cebes, at our friend's objection? --That was not my feeling, said Cebes; and yet I cannot deny that I am apt to be disconcerted.

Then we are agreed after all, said Socrates, that the opposite will never in any case be opposed to itself? --To that we are quite agreed, he replied.

Socrates' "complex" Theory of Forms

Yet once more let me ask you to consider the question from another point of view, and see whether you agree with me: There is a thing which you term heat, and another thing which you term cold? --Certainly. But are they the same as fire and snow? --Most assuredly not. Heat is not the same as fire, nor is cold the same as snow? --No.

And yet you will surely admit that when snow, as before said, is under the influence of heat, they will not remain snow and heat; but at the advance of the heat the snow will either retire or perish? --Very true, he replied. And the fire too at the advance of the cold will either retire or perish; and when the fire is under the influence of the cold, they will not remain, as before, fire and cold. --That is true, he said.

And in some cases the name of the idea is not confined to the idea; but anything else which, not being the idea, exists only in the form of the idea, may also lay claim to it. I will try to make this clearer by an example: The odd number is always called by the name of odd? --Very true.

But is this the only thing which is called odd? Are there not other things which have their own name, and yet are called odd, because, although not the same as oddness, they are never without oddness? — that is what I mean to ask — whether numbers such as the number three are not of the class of odd. And there are many other examples: would you not say, for example, that three may be called by its proper name, and also be called odd, which is not the same with three? and this may be said not only of three but also of five, and every alternate number — each of them without being oddness is odd, and in the same way two and four, and the whole series of alternate numbers, has every number even, without being evenness. Do you admit that? --Yes, he said, how can I deny that?

Then now mark the point at which I am aiming: not only do essential opposites exclude one another, but also concrete things, which, although not in themselves opposed, contain opposites; these, I say, also reject the idea which is opposed to that which is contained in them, and at the advance of that they either perish or withdraw.

There is the number three for example; will not that endure annihilation or anything sooner than be converted into an even number, remaining three? --Very true, said Cebes. And yet, he said, the number two is certainly not opposed to the number three? --It is not. Then not only do opposite ideas repel the advance of one another, but also there are other things which repel the approach of opposites. --That is quite true, he said.

Suppose, he said, that we endeavor, if possible, to determine what these are. --By all means. Are they not, Cebes, such as compel the things of which they have possession, not only to take their own form, but also the form of some opposite? --What do you mean?

I mean, as I was just now saying, and have no need to repeat to you, that those things which are possessed by the number three must not only be three in number, but must also be odd. --Quite true. And on this oddness, of which the number three has the impress, the opposite idea will never intrude? --No. And this impress was given by the odd principle? --Yes. And to the odd is opposed the even? --True. Then the idea of the even number will never arrive at three? --No. And three has no part in the even? --None. And the triad or number three is uneven? --Very true.

To return then to my distinction of natures which are not opposites, and yet do not admit opposites: as, in this instance, three, although not opposed to the even, does not any the more admit of the even, but always brings the opposite into play on the other side; or as two does not receive the odd, or fire the cold — from these examples (and there are many more of them) perhaps you may be able to arrive at the general conclusion that not only opposites will not receive opposites, but also that nothing which brings the opposite will admit the opposite of that which it brings in that to which it is brought. And here let me recapitulate — for there is no harm in repetition. The number five will not admit the nature of the even, any more than ten, which is the double of five, will admit the nature of the odd — the double, though not strictly opposed to the odd, rejects the odd altogether. Nor again will parts in the ratio of 3:2, nor any fraction in which there is a half, nor again in which there is a third, admit the notion of the whole, although they are not opposed to the whole. You will agree to that? --Yes, he said, I entirely agree and go along with you in that.

And now, he said, I think that I may begin again; and to the question which I am about to ask I will beg you to give not the old safe answer, but another, of which I will offer you an example; and I hope that you will find in what has been just said another foundation which is as safe. I mean that if anyone asks you "what that is, the inherence of which makes the body hot," you will reply not heat (this is what I call the safe and stupid answer), but fire, a far better answer, which we are now in a condition to give. Or if anyone asks you "why a body is diseased," you will not say from disease, but from fever; and instead of saying that oddness is the cause of odd numbers, you will say that the monad is the cause of them: and so of things in general, as I dare say that you will understand sufficiently without my adducing any further examples. --Yes, he said, I quite understand you.

Socrates' proof of the immortality of the soul

Tell me, then, what is that the inherence of which will render the body alive? --The soul, he replied. And is this always the case? --Yes, he said, of course.

Then whatever the soul possesses, to that she comes bearing life? --Yes, certainly. And is there any opposite to life? --There is, he said. And what is that? --Death.

Then the soul, as has been acknowledged, will never receive the opposite of what she brings. And now, he said, what did we call that principle which repels the even? The odd. --And that principle which repels the musical, or the just? --The unmusical, he said, and the unjust.

And what do we call the principle which does not admit of death? --The immortal, he said. And does the soul admit of death? --No. Then the soul is immortal? --Yes, he said. And may we say that this is proven? --Yes, abundantly proven, Socrates, he replied.

And supposing that the odd were imperishable, must not three be imperishable? --Of course. And if that which is cold were imperishable, when the warm principle came attacking the snow, must not the snow have retired whole and unmelted — for it could never have perished, nor could it have remained and admitted the heat? --True, he said. Again, if the uncooling or warm principle were imperishable, the fire when assailed by cold would not have perished or have been extinguished, but would have gone away unaffected? --Certainly, he said.

And the same may be said of the immortal: if the immortal is also imperishable, the soul when attacked by death cannot perish; for the preceding argument shows that the soul will not admit of death, or ever be dead, any more than three or the odd number will admit of the even, or fire or the heat in the fire, of the cold. Yet a person may say: "But although the odd will not become even at the approach of the even, why may not the odd perish and the even take the place of the odd?"

Now to him who makes this objection, we cannot answer that the odd principle is imperishable; for this has not been acknowledged, but if this had been acknowledged, there would have been no difficulty in contending that at the approach of the even the odd principle and the number three took up their departure; and the same argument would have held good of fire and heat and any other thing. --Very true.

And the same may be said of the immortal: if the immortal is also imperishable, then the soul will be imperishable as well as immortal; but if not, some other proof of her imperishableness will have to be given. --No other proof is needed, he said; for if the immortal, being eternal, is liable to perish, then nothing is imperishable. --Yes, replied Socrates, all men will agree that God, and the essential form of life, and the immortal in general, will never perish. --Yes, all men, he said — that is true; and what is more, gods, if I am not mistaken, as well as men.

Seeing then that the immortal is indestructible, must not the soul, if she is immortal, be also imperishable? --Most certainly. Then when death attacks a man, the mortal portion of him may be supposed to die, but the immortal goes out of the way of death and is preserved safe and sound? --True.

Then, Cebes, beyond question the soul is immortal and imperishable, and our souls will truly exist in another world! --I am convinced, Socrates, said Cebes, and have nothing more to object; but if my friend Simmias, or anyone else, has any further objection, he had better speak out, and not keep silence, since I do not know how there can ever be a more fitting time to which he can defer the discussion, if there is anything which he wants to say or have said.

But I have nothing more to say, replied Simmias; nor do I see any room for uncertainty, except that which arises necessarily out of the greatness of the subject and the feebleness of man, and which I cannot help feeling.