Metaphysics

​But in these opinions there is present much of the nature of the indeterminate, and of being in the way we have said. Therefore, they speak reasonably, but they do not speak truly (for it is more fitting to put it this way than as Epicharmus did against Xenophanes). Furthermore, seeing all this nature in motion, and that nothing is asserted truly of that which is changing, they concluded that about that which is changing in every way and in every respect it is impossible to speak truly. For from this supposition blossomed the most extreme of the mentioned opinions, namely that of those who claim to follow Heraclitus, and such as Cratylus held, who in the end thought that one ought to say nothing but only moved his finger, and censured Heraclitus for saying that it is not possible to step twice into the same river; for he himself thought not even once. But we shall say against this argument too that, while that which is changing, when it changes, gives them some reason to think that it does not exist, yet this is at least disputable; for that which is losing something still has something of that which is being lost, and of that which is coming to be, something must already exist; and on the whole, if it is being destroyed, there will exist something that is, and if it is coming to be, that from which it comes to be and that by which it is generated must exist, and this cannot go on to infinity. But leaving these things aside, let us say this: that to change in quantity is not the same as to change in quality; let it be, then, that in quantity a thing does not remain, but we know all things according to their form. Furthermore, it is worthy of censure in those who hold this opinion that, although they saw that this is the case only among the smaller number of sensible things, they declared in like manner about the whole heaven; for the region of the sensible around us alone is continually in destruction and generation, but this is, so to speak, no fraction of the whole, so that it would have been more just to acquit these because of those, rather than to condemn those because of these. Furthermore, it is clear that against these too we shall say the same things as were said before; for that there is some immovable nature must be shown to them, and they must be convinced of it. And yet, it happens to those who say at the same time that a thing is and is not, that they must say all things are at rest rather than in motion; for there is nothing into which they can change, for all things are already present in all. And concerning truth, to show that not every appearance is true, first of all, even if sensation is not false concerning its own proper object, yet imagination is not the same as sensation. Next, it is a wonder if they are in doubt about this: whether magnitudes are of such a size and colors of such a kind as they appear to those at a distance or to those nearby; and whether they are such as they appear to the healthy or to the sick; and whether those things are heavier which seem so to the weak or to the strong; and whether those things are true which appear to the sleeping or to the waking. For that they do not really think so is clear; at least, no one, if he supposes at night that he is in Athens when he is in Libya, sets out for the Odeum. Furthermore, concerning the future, as Plato also says, the opinion of the physician and that of the ignorant person are surely not of equal authority, for example, about whether someone is going to be healthy or not. Furthermore, in the case of the senses themselves, the authority of a foreign sense and that of the proper sense, or that of a neighboring sense and that of its own, are not equal; but sight, not taste, is authoritative concerning color, and taste, not sight, concerning flavor; and none of these senses ever says at the same time, concerning the same thing, that it is both so and not so. Nor indeed at another time does a sense ever dispute about the affection itself, but only about that to which the affection happens. I mean, for example, the same wine might seem, either because it has changed or because one’s body has changed, to be at one time sweet and at another not sweet; but the sweet itself, such as it is when it exists, has never changed, but is always true about itself, and that which is to be sweet is of necessity of such a nature. Yet all these arguments destroy this; just as they deny that there is any substance of anything, so they deny that anything is of necessity; for that which is necessary cannot be otherwise and otherwise, so that if anything is of necessity, it will not be both so and not so. And on the whole, if only the sensible exists, nothing would exist if animate things did not exist; for there would be no sensation. Now, that neither the objects of sensation nor the sensations themselves exist is perhaps true (for this is an affection of the sensing subject), but that the underlying subjects which produce sensation do not exist, even without sensation, is impossible. For sensation is surely not of itself, but there is also something else besides sensation, which must of necessity be prior to sensation; for that which moves is by nature prior to that which is moved, and this is no less true even if they are spoken of in relation to each other.