Commentary Aristotle Posterior Analytics
Lecture 24
How there is demonstration quia through things not immediately connected b13. This also occurs (1) when the middle falls outside the major and minor, for here too the strict cause is not given, and so the demonstration is of the fact, not of the reasoned fact.
b14. For example, the question ‘Why does not a wall breathe?’ might be answered, ‘Because it is not an animal’; but that answer would not give the strict cause, because if not being an animal causes the absence of respiration, then being an animal should be the cause of respiration, according to the rule that if the negation of x causes the non-inherence of y, the affirmation of x causes the inherence of y; e.g., if the disproportion of the hot and cold elements is the cause of ill health, their proportion is the cause of health; and conversely, if the assertion of x causes the inherence of y, the negation of x must cause y’s non-inherence. But in the case given this consequence does not result; for not every animal breathes.
b24. A syllogism with this kind of cause takes place in the second figure. Thus: let A be animal, B respiration, C wall. Then A is predicable of all B (for all that breathes is animal), but of no C; and consequently B is predicable of no C; that is, the wall does not breathe.
b27. Such causes are like far-fetched explanations, which precisely consist in making the cause too remote, as in Anacharsis’ account of why the Scythians have no flute-players; namely because they have no vines.
b32. Thus, then, do the syllogism of the fact and the syllogism of the reasoned fact differ within one science and according to the position of the middle terms.
This also occurs when the middle. After clarifying with examples how there is demonstration 'quia' through effect, the Philosopher here shows how there is demonstration 'quia' through things not immediately connected.
About this he does two things.
First, he amplifies his proposition.
Second, he shows how the middles relate themselves to the conclusions in this type of demonstration, at: such causes are like far-fetched (78b27; [205]).
Concerning the first he does three things.
First, he states his intention.
Second, he clarifies it with examples, at: for example, the question (78b14; [203]).
Third, he puts it in syllogistic form, at: a syllogism with this kind (78b24; [204]).
He says therefore first (78b13) that there is demonstration 'quia' and not 'propter quid' not only in those matters that are proved through an effect but also in matters in which the middle is set outside.
Now, a middle is said to be set outside when it is diverse from the minor term, as in negative syllogisms; or a middle is said to be set outside when it is outside the genus as being something more common and not convertible with the major term. That something cannot be demonstrated 'propter quid' through such a middle he proves on the ground that demonstration 'propter quid' is through a cause. But the middle in question is not, properly speaking, a cause.
Then, at: for example, the question (78b14) he clarifies what he had said with an example, saying that if someone attempted to prove that a wall does not breathe because it is not an animal, he would not be demonstrating 'propter quid' or giving the cause. Because if the fact of not being an animal were the cause of not breathing, it would be required that being an animal would be the cause of breathing—which is false. For there are many animals which do not breathe. For it is required, if a negation is the cause of a negation, that the affirmation be the cause of the affirmation, as the fact of not being warm and cold in due measure is the cause of someone’s not getting well, and to be warm and cold in due measure is the cause of someone’s getting well. The converse is also true, namely, that if an affirmation is the cause of an affirmation, the negation is the cause of the negation. But this does not occur in the case at hand, because the affirmation is not the cause of an affirmation, since not every animal breathes.
Then, at: a syllogism with this kind (78b24) he arranges the aforesaid example in syllogistic form and says that it should be arranged in the second figure.
And this is so because in the first figure there cannot be a negative conclusion such that the major would be affirmative, as our example requires. For “to breathe,” which is the major extreme, must be joined with “animal,” which is the middle term, according to affirmation. But “wall,” which is the minor extreme, must be joined with “animal,” which is the middle, according to negation. Consequently, the major will be affirmative and the minor negative. But such a thing never occurs in the first figure, but only in the second.
Let “animal,” then, be A, that is, the middle term, “breathe” be B, that is, the major extreme, and “wall” be C, that is, the minor extreme. It therefore follows that A is in every B, because everything that breathes is an animal; but A is in no C, because no wall is an animal. Hence it follows that B, too, is in no C, that is, that no wall breathes.
Furthermore, if the most proximate middle were used, it would be demonstration 'propter quid': for example, if it were shown that a wall does not breathe because it does not have lungs. For whatever has lungs breathes, and conversely.
Then, at: such causes are like far-fetched (78b27) he shows how these middles are related to the conclusion, saying that such far-away causes are compared to what they explain as being too remote, because they go beyond the pale of the conclusion to be proved. Furthermore, a middle of this sort happens to assign what is far-fetched, as in Anacharsis’ proof that there are no flutists among the Scythians because there are no vines there. For this is quite a far-fetched middle. A nearer one would be that they have no wine, and nearer still, that they do not drink wine, from which follows a merry heart which moves one to sing—if 'fluting' is taken to mean singing. Or it might be better to say that 'fluting' is not taken for just any singing but for the song of the grape harvesters, called “celeuma.”
Then, at: thus, then, do the syllogism (78b32) he summarizes what he had said and declares that these are the differences between the syllogism 'quia' and the syllogism 'propter quid' in the same science, and according to the position of the same, that is, of those that have the same order. This he says to exclude what he will discuss later, namely, that one science is under another.