With Anaxagoras we move once more back to eastern Greece whence philosophy had originally come. We have seen that Anaxagoras was older than Empedocles, but that he began his philosophical activity later than the Sicilian. This would be helpful if we could achieve more determination about Empedocles' dates and if we did not have the puzzling information to the effect that Anaxagoras came to Athens and began philosophizing at the age of twenty. It may be safe enough to think of him as flourishing about 460 B.C. We are told that Anaxagoras was forced to flee Athens and that he died at Lampsacus. We need not here go into the speculation and discussions about when and why he left Athens. Anaxagoras is said to have studied under Anaximenes, but this remark seems prompted by certain doctrinal tenets.
Anaxagoras is said to have written only one book; this seems virtually certain, although in late antiquity many writings were attributed to him. We have a little over twenty fragments of his book and they are such that we can surmise that we have the core of his doctrine. That doctrine seems to be a quite conscious response to the challenge of Parmenides' way of truth; and Anaxagoras answers it in a way that goes beyond the efforts of Empedocles, though somewhat in the same line. The tenor of his solution is found in the first fragment.
All things were together, infinite both in number and in smallness; for the small too was infinite. And, when all things were together, none of them could be distinguished for their smallness. For air and aether prevailed over all things, being both of them infinite; for amongst all things these are the greatest both in quantity and size. (Fr. 1)
Simplicius, who has preserved most of the fragments we have of Anaxagoras, tells us that this remark was the first in Anaxagoras' book. We are immediately apprized of Anaxagoras' way of handling Parmenides. If things cannot come to be, we need not conclude with Parmenides that there is but one unchanging thing; rather let us say that in the beginning everything, the whole variety of things of our sense experience, was present in a confused whole. That is, if nothing can be said to come to be, let everything exist from the beginning, since thereby we can save what our senses tell us and not violate the Eleatic logic.
But before they were separated off, when all things were together, not even was any color distinguishable; for the mixture of all things prevented it -- of the moist and the dry, and the warm and the cold, and the light and the dark, and of much earth that was in it, and of a multitude of innumerable seeds in no way like each other. For none of the other things either is like any other. And these things being so, we must hold that all things are in the whole. (Fr. 4)
It is not mere conjecture that Anaxagoras begins as he does because of what Parmenides had taught.
The Hellenes follow a wrong usage in speaking of coming into being and passing away; for nothing comes into being or passes away, but there is mingling and separation of things that are. So they would be right to call coming into being mixture and passing away separation. (Fr. 17)
Empedocles had met the difficulty by speaking of the four roots of all things, the elements which alone are fire, air, earth and water. Anaxagoras accepts the diversity of things and says that something like gold is not to be reduced to non-gold as to its elements, but rather to particles of gold, particles which must be thought of ultimately as infinitesimally small but of the same nature as that with which we began. "How can hair come from what is not hair, or flesh from what is not flesh?" (Fr. 10)
We have here a much more radical heeding of the argument of the way of truth. To say, as Empedocles had, that what we call the coming into being of something like flesh is a new combination of elements, themselves not flesh, seems to give too much meaning to becoming. If, on the other hand, before flesh comes to be, as we would say, it has already existed as flesh, but as very small particles, then the notion of becoming is too strong to describe what is happening, and we would do better to speak of mingling and separation. If we take something like flesh and think of it as being broken into smaller particles of flesh, and each of those as being further broken down, we will never, Anaxagoras maintains, come to an end.
Nor is there a least of what is small, but there is always a smaller; for it cannot be that what is should cease to be by being cut. But there is also always something greater than what is great, and it is equal to the small in amount, and, compared with itself, each thing is both great and small. (Fr.3)
If fragments quoted earlier seem to refer to Parmenides, this one, as Kirk and Raven have argued (pp. 371-2), seems clearly to have Zeno in mind. The paradoxes of Zeno were directed against those who confused physical and mathematical magnitude. In mathematics, we can speak of infinite divisibility, but Zeno attempted to show that we encounter insurmountable difficulties if we think of physical extension in this way. Anaxagoras refuses to be intimidated and appears to insist quite consciously on the infinite divisibility of physical matter. There is no end to the process whereby flesh could be cut down into small particles of flesh; and just as that with which we begin has magnitude, so too must the infinity of infinitely small particles it contains. Thus, no matter how small the particle of flesh we imagine, it is great because it can be further subdivided into parts of the same kind. Aristotle uses the word homoeomeries to convey this notion that the parts of the whole are of the same nature as the whole. Difficult as it is, Anaxagoras is deliberately saying that something like flesh has this in common with the line that however far you divide it, you will still be left with smaller versions of that with which you began. The assertion that things are at once great and small seems clearly an open retort to Zeno.
Thus far the view of Anaxagoras would seem to lead to an image of the world according to which things are rigorously set off from each other, since the parts of any thing are simply smaller instances of its nature. Flesh and bone, then, would seem to have nothing in common. A first corrective to this is Anaxagoras' cosmogonical remark about the way things were first of all. In Fragment I we find Anaxagoras speaking of when all things were together, at which time they were indistinguishable because of their smallness. So too in Fragment 4, quoted before, we read of the innumerable seeds present in the original mass where none of the opposites was yet obvious. More emphatically, Anaxagoras maintains that everything is in everything.
And since the portions of the great and of the small are equal in amount, for this reason, too, all things will be in everything; nor is it possible for them to be apart, but all things have a portion of everything. Since it is impossible for there to he a least thing, they cannot be separated, nor come to be by themselves; but they must be now, just as they were in the beginning, all together. And in all things many things are contained, and an equal number both in the greater and in the smaller of the things that are separated off. (Fr.6)
This would mean that we could take any object in the universe and it would contain within itself everything else. Change, consequently, would involve the separation off of some particles so that the original object would appear different afterwards than it had before what we call the change took place. Not that there could be a complete depletion of particles of a certain kind from a given physical object. There is an infinity of particles of any given type in anything both before and after what we would call a change.
Now, as Aristotle pointed out, this leads to a perplexing question. If anything contains everything, why do we call some things flesh, others bone, yet others gold, etc.? Anaxagoras' equally perplexing answer, according to Aristotle, is that what we call flesh has more portions of flesh than anything else -- although of course it has an infinity of parts of anything else. It is well to recall once more why Anaxagoras is putting forward this paradoxical doctrine. If everything is in anything, then no change, however surprising, is going to involve the coming into being of something which did not exist before. Aristotle gives a more concrete and plausible statement of this motivation. Anaxagoras accepted the rather obvious fact that a thing seems to arise from its opposite and its opposite again from it, hot from cold, dry from wet. Now Anaxagoras, given the Parmenidean way of truth, would not want to say that before hot comes to be, hot did not exist; therefore, he is led to say that hot already existed in the cold, that it was there in parts and particles, and that when portions of cold are removed we notice the portions of hot and designate the object accordingly. Such a process could never be completed, however, as if all the particles of cold might be removed: everything is in everything. "The things that are in one world are not divided nor cut off from one another with a hatchet, neither the warm from the cold nor the cold from the warm." (Fr. 8)
The perplexing thing about the theory of Anaxagoras is that his cosmogony seems repeatable in every particular thing in the world. That is, he speaks of all things being together in the beginning, present in one mass in infinitely small particles so that the whole would not seem to have any particular nature, except perhaps that of air or aether. (Fr. 1) Then begins a process of separating off. "For air and aether are separated off from the mass that surrounds the world, and the surrounding mass is infinite in quantity." (Fr.2) This separation is accomplished by a whirling motion (Fr. 13), and after separating, things begin to mingle again.
The dense and the moist and the cold and the dark came together where the earth is now, while the rare and the warm and the dry (and the bright) went out towards the further part of the aether. (Fr. 15)
In the area of the earth, the things that we know appear. "From these as they are separated off earth is solidified; for from mists water is separated off, and from water earth. From the earth stones are solidified by the cold, and these rush outwards more than water." (Fr. 16) Thus far, the doctrine of Anaxagoras emerges as an ingenious if difficult attempt to circumvent the difficulties Parmenides had posed for those who would accept motion and change and multiplicity as requiring no explanation. Anaxagoras is more thoroughgoing in his attempt to have change without novelty, becoming without any alteration of the things that are; but the difference would seem to be one of degree rather than kind.
There is a good deal more than this in the fragments of Anaxagoras, an element of doctrine that caused Aristotle to say that he sounded like one sober man in a chorus of drunks (Metaphysics I 3,984b15-18). Aristotle is referring to Anaxagoras' doctrine of Nous or Mind. The few things said about Mind in the fragments indicate that a great advance is being made, a positive contribution, and not simply an ingenious reaction.
If everything is in everything, there is at least one exception to this dictum.
All other things partake in a portion of everything, while Nous is infinite and self-ruled, and is mixed with nothing, but is alone, itself by itself. For if it were not by itself, but were mixed with anything else, it would partake in all things if it were mixed with any; for in everything there is a portion of everything, as has been said by me in what goes before, and the things mixed with it would hinder it, so that it would have power over nothing in the same way that it has now being alone by itself. For it is the thinnest of all things and the purest, and it has all knowledge about everything and the greatest strength; and Nous has power over all things, bothgreater and smaller, that have life. And Nous had power over the whole revolution, so that it began to revolve from the beginning; but the revolution now extends over a larger space, and will extend over a larger still. And all the things that are mingled together and separated off and distinguished are all known by Nous. And Nous set in order all things that were to be, and all things that were and are not now and that are, and this revolution in which now revolve the stars and the sun and the moon, and the air and the aether that are separated off. And this revolution caused the separating off, and the rare is separated off from the dense, the warm from the cold, the light from the dark, and the dry from the moist. And there are many portions in many things. But no thing is altogether separated off nor distinguished from anything else except Nous. And all Nous is alike, both the greater and the smaller; while nothing else is like anything else, but each single thing is and was most manifestly those things of which it has most in it. (Fr. 12)
Empedocles of course had introduced a pair of causes beside the elements to account for the changes that occur. Anaxagoras speaks of Nous, of Mind, as the motive force behind the revolution, causing the separating off from the primal whole and the consequent constitution of our world. Why does this make Anaxagoras more deserving of praise than Empedocles? One way would be to suggest that when Empedocles wants to explain what he means by love he says that men have felt it as they feel the effects of Aphrodite. Now this would suggest being propelled along a given course of action, rather than choosing it with reason; and, indeed, Empedocles does not want to suggest that cosmological processes take place otherwise than by chance. Moreover, love and strife or hate are manifestly corporeal for Empedocles, just as thought is the surging of blood about the heart. The Nous of Anaxagoras is described in such a way that it seems quite clear that he is striving in a wholly new way to speak of a principle which transcends the material order. Nous is unmixed, it does not contain portions of all things; and it is this freedom from admixture which is said to explain both its power over all things and its ability to know all things. This way of speaking of knowledge goes quite a distance beyond Empedocles' explanation, whereby knowing was like answering to like. Here it is utter difference in nature which underlies knowledge. The dichotomy between Nous and the material world is sharply described in the long fragment we have just quoted. Nous is over against the cosmos; unmixed, itself by itself. If it contained any bit of physical matter it would contain all, since everything is in everything. Thus Anaxagoras speaks of Nous as thinnest and purest, striving to express what is utterly unlike the other things he is speaking of. Nous directs the cosmogonical process and continues to govern the movements of the heavens and this means that things do not come about by chance. They are caused by mind, by intelligent direction. Later Greeks -- Socrates and Aristotle -- could not refrain from praising Anaxagoras for stating that the world involves rational direction, intelligence; if they then went on to make reservations about the use to which Anaxagoras put this new principle -- reservations we shall discuss presently -- we should not let this distract us from the magnificence of Anaxagoras' contribution to Greek philosophy. The world is no longer something that just happened, that is, a state consequent on a previous state for purely mechanical reasons; it is caused by a rational principle who initiates the process, and, thanks to his unmixed nature, knows and has power over all things.
In the Phaedo, Plato allows Socrates to speak of how overjoyed he was when he found that Anaxagoras had taught that all things were directed by Mind; and yet Socrates was disappointed because the principle remained so abstract and Anaxagoras had not employed it in any particular explanation. Aristotle suggests that Anaxagoras, despite the merit of his introduction of Nous to explain the cosmogonical process, has set Nous an impossible task. Nous is given as the cause of separating off; but this, according to Anaxagoras, is a process which can never achieve its term. Thus, Mind is engaged in an irrational enterprise. As Freeman points out (p. 269), the complaint of Socrates is not wholly justified, since Nous is said to be the cause of whatever was, is, or will be; the statement may be general, but it could hardly be more comprehensive. Aristotle's criticism would be a good deal harder to meet, and Anaxagoras' doctrine acquires, in the face of it, a bifurcated look. On the one hand there is his strange and difficult response to Parmenides; on the other, the new principle, Nous, the directing cause of whatever goes on in the physical world.
Doubtless we must caution ourselves against attributing too much to Anaxagoras, as if his doctrine on the Nous emerges unequivocally from the few fragments we possess. We have seen earlier attempts -- the first notable one being that of Xenophanes -- to achieve clarity in speaking of what is beyond the things grasped by the senses. Obviously, the way which proceeds by negating of such a principle the qualities of physical things is the only way open to us. So Xenophanes denies that the divine is at all like men or other things. So, too, Parmenides would speak of a being which is devoid of all sensible qualities -- although it seems to have spatial extension. Despite the dangers of exaggeration, it seems undeniable that Anaxagoras has taken a significant step beyond earlier efforts to speak of a principle which is other than physical things. What is more, as Aristotle liked to point out, the dissimilarity of Nous with physical things is explained in function of such activities as knowledge and governing. If Anaxagoras is making a significant forward step in the effort to transcend the material, it is equally true that there is still a long way to go; only with Plato and Aristotle, and with significantly different underpinning, will we encounter clearcut statements of entities beyond the material. From the vantage point of their achievements, a backward glance at the contribution of the first Greek philosopher associated with Athens will enable us to make another and perhaps surer appraisal of the extent of that contribution.
The doctrines of Empedocles and Anaxagoras are not the last efforts by presocratic philosophers to escape the dilemma Parmenides had posed for natural philosophy. Extreme as their doctrines may seem as reactions to the Eleatic philosopher, there is another species of pluralism, atomism, to which we must now turn.