Which Dog Do You Mean

Every question is settled out of knowledge that was there already. And the knowledge we already have of whatever is being investigated is sometimes only of its essence, while what it does remains unknown — as with stones and plants and animals, whose workings we do not know. Or it may be knowledge of the thing’s properties, or its powers, or, so to speak, the qualities that belong to it. Sometimes we know one or more of those powers or properties — the desires and feelings of the soul, for instance — and do not know the essence, and it is the essence we then set out to investigate. But often our understanding has taken in all of these, and the question is which of the essences they belong to; for it is only after we have formed a conception of both in our minds, of the essence and of the operation alike, that we go on to the question. And there are also things whose operation we know along with their essence, but whose modifications we do not know. [a]

This, then, is the method of discovery. We have to begin by knowing what the questions under discussion are. For the form an expression takes often deceives the mind, and confuses and unsettles it, so that it is not easy to find out what class a thing is to be put in — whether the fetus, for example, is an animal. Having a conception of an animal and a conception of a fetus, we ask whether it is in fact the case that the fetus is an animal: that is, whether the substance that is in the fetal state has the power of motion, and of sensation besides. So the inquiry is about functions and sensations in a substance we already know. Which means that the man who puts the question must first be asked what he calls an animal. This is to be done above all when we find the same term used for various purposes, and we must examine whether what the term means is in dispute or agreed on by everyone. For if someone were to say that he calls whatever grows and is fed an animal, we shall have to ask him further whether he counts plants as animals; and then, once he has declared himself on that, he must show what it is that is in the fetal state and is being nourished. Plato calls plants animals, on the ground that they share in the third kind of life alone, the life of appetite. Aristotle, on the other hand, thinks plants have a life of growth and nourishment, but does not think it proper to call them animals; only what has the other life, the life of sensation, does he think may rightly be called an animal. The Stoics do not call the power of growth life at all.

Now if the man who put the question denies that plants are animals, we shall show that what he says contradicts itself. For having defined an animal by the fact that it is nourished and grows, and then having asserted that a plant is not an animal, he appears to be saying nothing except this: that what is nourished and grows is both an animal and not an animal. So let him say what he wants to learn. Is it whether what is in the womb grows and is nourished? Or is it whether it has any sensation, or any motion of its own impulse? For according to Plato the plant is ensouled, and an animal; according to Aristotle it is not an animal, since it lacks sensation, but it is ensouled. On his view, then, an animal is an ensouled thing that has sensation. But according to the Stoics a plant is neither ensouled nor an animal, since an animal is an ensouled thing. If, then, an animal is ensouled, and life is a nature that has sensation, plainly what is ensouled has sensation. And if the man who put the question, on being asked again, still calls what is in the fetal state an animal because it is nourished and grows, he has his answer.

But if he says that what he is asking is whether the fetus already has sensation, or is capable of moving itself by some impulse, then the matter under investigation becomes clear and the trick played by the word is gone. If, however, he will not answer the question, and will not say what he means, or in what respect he is applying the word “animal” in putting the question, but tells us to define it ourselves, let him be set down as a man who only wants to argue. There are two methods, one by question and answer, the other by exposition. If he declines the first, let him listen while we set out everything that bears on the problem. Then, when we have finished, he may take up each point in turn. But if he tries to break into the inquiry by putting questions, he plainly does not want to hear. If he chooses to answer, let him first be asked what he applies the name “animal” to. And when he has answered that, let him be asked next what he takes “fetus” to mean — what is in the womb, or things already formed and living; and again, whether “fetus” means the seed once it has been deposited, or whether the name “embryo” is only to be used once limbs and a shape have formed. And on his replying to that, the point at issue should be reasoned out to a conclusion in due order, and taught.

But if he wants us to speak without answering, let him listen. Since you will not say in what sense you assert what you have put forward — for I would not have entered a discussion about meanings at all; by now I would have been looking at the things themselves — understand that you have done exactly as if you had put the question, is a dog an animal? For I might rightly have said: which dog do you mean? I shall speak of the land dog and the sea dog, and the one in the sky, and of Diogenes too, and of all the other dogs in order. I could not divine whether you were asking about all of them or about some one of them. What you will have to do afterward, do now: say distinctly what your question is about. Now if you are shuffling names about, it is plain to everybody that the name “fetus” is neither an animal nor a plant, but a name, and a sound, and a body, and a being, and anything and everything rather than an animal. And if that is what you have put forward, you have your answer.

Nor, again, is what the name “fetus” signifies an animal. That is incorporeal, and may be called a thing and a notion and everything rather than an animal. The nature of an animal is something else. For the very point in question was clearly shown — I mean the nature of the embryo, what sort of thing it is. The question about what is meant by the name “animal” is a different question. I say this, then. If you assert that an animal is what has the power of sensation and of moving itself by its own impulse, an animal is not simply what is at this moment moving by impulse and exercising sensation. For it is also capable of sleeping, or, when there is nothing present to be sensed, of not exercising the power of sensation. It is the natural power of impulse or of sensation that is the mark of an animal, and something of this sort is what these considerations indicate. First, whether the fetus is incapable of sensation or of motion by impulse — which is the point put forward for consideration. The other point is whether the fetus is capable of ever exercising sensation or of moving by impulse; and in that sense nobody makes it a question, since it is evident.

But the question was whether the embryo is already an animal or still a plant. And then the name “animal” was brought down to a definition, for the sake of clarity. Having found that it is marked off from what is not an animal by sensation and by motion from impulse, we went on to separate that from what goes along with it. We said that it is one thing to be such potentially — not yet possessing the power of sensation and motion, but going to possess it at some point — and another thing to be so already, in act; and that in the second case it is one thing to be exercising the powers and another to be able to exercise them while at rest or asleep. And that is the question. The embryo is not to be called an animal on the ground that it is nourished. That is the allegation of people who turn aside from the essence of the question and give their minds to something else that happens to be true of it. But in every case where a conclusion is claimed to have been found out, demonstration is applied in common; and demonstration is reasoning that establishes one thing from others. The grounds from which the point at issue is to be established must be granted and known by the learner. And the foundation of all of them is what is evident to the senses and to the intellect.

So the primary demonstration is put together out of all of these. But a demonstration which uses points already demonstrated by the first one to establish some further point is no less reliable than the first. It simply cannot be called primary, because its premises are not first principles. That, then, is the first of the three kinds of question set out — the kind in which the essence is known and some one of its powers or properties is not. The second sort of proposition was the one in which we all know the powers and the properties, but do not know the essence: for example, in what part of the body the governing faculty of the soul is.

The same treatment that applies to demonstration applies to the following question as well. Some, for instance, say that there cannot be several originating causes for one animal. It is impossible that there should be several originating causes of the same kind for one animal; but that there should be several of different kinds is not absurd. Take the Pyrrhonian suspension of judgment — the idea, as they call it, that nothing is certain. It is plain that, beginning with itself, it invalidates itself first. Either it grants that something is true, namely that you are not to suspend judgment about everything; or it goes on insisting that nothing is true. And it is evident that in the first place it will not itself be true. For it either asserts what is true or it does not assert what is true. If it asserts what is true, it concedes, unwillingly, that something is true. And if it does not assert what is true, it leaves standing as true the very thing it wanted to do away with. For so far as the skepticism that demolishes is proved false, so far the positions being demolished are proved true — like the dream that says all dreams are false. In confuting itself it confirms the others. [l]

And in short, if it is true, it will make a beginning with itself, and be skepticism about nothing else before it is skepticism about itself. Then if such a man apprehends that he is a man, or that he is a skeptic, it is evident that he is not a skeptic. And how is he to reply when he is questioned? For he is evidently no skeptic on this point. He even asserts that he does doubt. And if we must be persuaded to suspend judgment about everything, we shall first suspend judgment about the suspension of judgment itself — whether we are to credit it or not. And if this position is true, that we do not know what is true, then absolutely nothing is allowed by it to be true. But if he will say that even this is open to question, whether we know what is true, then by that very statement he grants that truth can be known, at the very moment when he appears to be establishing the doubt about it.

But suppose a philosophical school is an inclination toward doctrines — or, as some put it, an inclination toward a number of doctrines that are consistent with one another and with what appears, and that tend toward a right life; and suppose a doctrine is a conception arrived at by reasoning, and a conception is a state and an assent of the mind. Then it is not skeptics only: everyone who holds doctrines is in the habit of suspending judgment in certain things, either through want of strength of mind, or through want of clearness in the things themselves, or because the reasons on either side are of equal force.