LECTURE 9 (213 a 11-b 20)

THE TREATMENT OF THE VOID PERTAINS TO NATURAL PHILOSOPHY.

&OPINIONS AND ARGUMENTS AFFIRMING AND DENYING THE EXISTENCE OF THE VOID

             494. After the Philosopher has treated place, he here treats the void.

             Concerning this he makes two points. First, he explains his intention. Secondly, where he says, 'Those who try to show . . .' (213 a 23), he takes up what he has proposed.

             Concerning the first part he makes two points. First he shows that the treatment of the void pertains to natural philosophy. Secondly, where he says, 'We must begin . . .' (213 a 20), he explains the order in which the void must be treated.

             He says, therefore, first that just as the treatment of whether place is and what place is pertains to natural philosophy, so does the treatment of the void. For through similar arguments some have believed and some have disbelieved in the existence of place and the void. Those who say that a void exists posit it as a certain place and a certain vase. For indeed a vase or a place seems to be full when it has in itself the mass of some body; and when it does not, it is said to be void. It is as if place, the void, and the plenum are the same in subject, and differ only according to reason [ratio].

             495. Next where he says, 'We must begin . . .' (213 a 20), he explains the order in which the void must be treated.

             He says that it is necessary to begin by giving the arguments of those who say that a void exists, next the arguments of those who say that a void does not exist, and lastly common opinions about the void, that is, what pertains to the nature [ratio] of a void.

             496. Next where he says, 'Those who try to show . . .' (213 a 23), he does what he has said.

             First he sets forth those things which are necessary for seeking the truth about the void. Secondly, where he says, 'Let us explain again . . .' (214 b 13), he begins to seek out the truth.

             Concerning the first part he makes two points. First he gives the arguments of those who affirm and of those who deny the existence of a void. Secondly, where he says, 'As a step towards . . .' (213 b 30), he gives the common opinion of the void, showing what is the nature [ratio] of the void.

             Concerning the first part he makes two points. First he gives the argument of those who deny the existence of a void, and secondly, where he says, 'They argue, for one thing . . .' (213 b 4), the arguments of those who affirm the existence of a void.

             497. He says, therefore, first that some of the ancient philosophers, wishing to show that a void does not exist, erred in that they did not argue against the reasoning of those who hold that a void does exist. For they did not show that a void does not exist. Rather they brought in their own arguments to show that that which is full of air is not a void. This is true of Anaxagoras and others who argue in similar ways. To deny a void they wished to show that air is something, and thus, since a void is that in which nothing is, it follows that that which is full of air is not a void.

             They showed that air is something by arguing with their adversaries by means of bags made of animal skin, which, when inflated, can sustain something heavy. This could not be unless air were something. Thus they showed that air is resistant. They also showed this by putting air in clepsydras (that is, in vases which withdraw water) into which water is drawn when the air is withdrawn. Furthermore the entrance of the water is impeded unless the air is removed.

             It is clear, therefore, that these men do not object to the position. For everyone who holds that a void exists wishes it to be a void of space in which there is no sensible body. The reason for this is that they think that everything which is is a sensible body, and thus, where there is no sensible body, they believe that there is nothing. Hence, since air is a moderately sensible body, they think that, where there is nothing except air, there is a void.

             498. Therefore, to refute their position it is not sufficient to show that air is something. Rather it is necessary to show that there is no space without a sensible body. Further some posit the existence of a void in two ways: first as something separated from bodies, as if we would say that the space which is between the extremities of a house is a void; secondly as actually existing within bodies and distinguishing bodies from each other so that they are not continuous, as Democritus, Leucippus, and many other natural philosophers have said. For they imagine that if the whole of being were continuous, everything would be one. For there would be nothing to determine why bodies should be distinguished here rather than there. Hence between all distinct bodies they held that a spatial void intervenes in which there is no being. And since Democritus held that bodies are composed of many indivisible bodies, in the intervals between these indivisible bodies he posited certain voids, which he called 'pores'. Thus he said that all bodies are composed of the plenum and the void. And even if the whole body of the world is a continuum and there is no void between the parts of the universe, nevertheless they held that there is a void outside the whole world.

             Therefore, it is clear that the above mentioned philosophers who wish to refute the void do not bring in arguments on the question according to the position of the others. For they ought to have shown that there is no void in any of these ways.

             499. Next where he says, 'They argue, for one thing . . .' (213 b 4), he gives the arguments of those who affirm that a void exists. First he gives the arguments of those who have spoken of the void in terms of nature, and secondly, where he says, 'The Pythagoreans, too . . .' (213 b 23), of those who have not spoken of the void in terms of nature.

             Concerning the first part he makes two points. First he gives the argument of those who hold that the void is a certain space separated from bodies, and secondly, where he says, 'They reason from the fact . . .' (213 b 15), of those who hold that there is a void in bodies.

             Concerning the first part he makes two points. First he gives the argument of those who hold that there is a void. Secondly, where he says, 'Melissus, indeed, infers . . .' (213 b 12), he explains how Melissus contrariwise used that argument.

             500. He says, therefore, first that those who affirm that the void exists bring in better arguments for their position.

             One of these is that motion in respect to place, that is, change of place and augmentation, as was said above, could not be if there were no void. They explained this as follows. If something is moved in respect to place, it cannot be moved in a plenum. For a place which is filled by one body cannot receive another. If it could receive another, it would follow that there are two bodies in the same place. And for the same reason, this would be true of everything, for one could not establish any reason why two bodies and not more are in the same place. Now if this happened, namely, that many bodies are in the same place, then it would follow that the smallest place could receive the largest body, because many small things constitute one large thing. Hence if many small equal things are in the same place, so also can many unequal things. Therefore, having proven this conditional statement--that if there is motion, there is a void--they argue by positing the antecedent: motion exists, therefore a void exists.

             501. Next where he says, 'Melissus, indeed, infers . . .' (213 b 12), he shows that Melissus, having assumed the same conditional statement, argued to the contrary by denying the consequent. If there is motion, there is a void; but there is no void; hence there is no motion. Therefore, all being is immobile.

             This, then, is one way in which some have proven that there is a void as something separated.

             502. Next where he says, 'They reason from the fact . . .' (213 b 15), he gives three arguments from those who hold that there is a void in bodies.

             The first of these deals with things that are condensed. In things which are condensed, the parts seem to come together or meet each other, and to trample on and compress each other. Thus the example is given that jars receive as much wine with bags as without bags, especially if the bags are thin, because the wine seems to be condensed in the bags. They thought that this condensation happened as if the body became more dense by parts entering into certain voids.

             503. He gives the second argument, which deals with increase, where he says, 'Again increase, too . . .' (213 b 19).

             Bodies are increased through nourishment, which is a certain body. But two bodies cannot be in the same place. Therefore in bodies which are increased there must be some voids into which the nourishment is received. Thus, in order for nourishment to be received, there must be a void.

             504. He gives the third argument where he says, 'A proof of this . . .' (213 b 21). This argument deals with a vase filled with ashes. This vase receives as much water as it would when empty. This could not be unless there are some voids between the parts of the ashes.

             505. Next where he says, 'The Pythagoreans, too . . .' (213 b 23), he gives the opinions of those who do not speak of the void in terms of nature.

             He says that the Pythagoreans also affirm the existence of a void, which enters into the parts of the world from the heavens because of the infinite void which they thought exists outside the heavens as a certain air or infinite breath. And as one who breathes divides by his own breathing something that is easily divisible, like water and such things, likewise distinction enters into things as from something that is breathing. They thought that this occurs only by means of a void, as was said of Democritus, as if the void were nothing else than the distinction of things. And since the first distinction and plurality is found in numbers, they placed the void primarily in numbers. Thus through the nature of the void one unity is distinguished from another so that number is not continuous but discrete in nature. But since they have spoken, as it were, equivocally about the void, calling it the distinction of things, this opinion is not examined any further in what follows.

             Lastly he concludes that he has now indicated why some say that there is a void and why some do not.