Of the use of equivocal premisses, hypothetical arguments and the like
1Most men are unaware that the handling of arguments which involve equivocal and hypothetical premisses, and, further, of those which derive syllogisms by the process of interrogation, and, in general, the handling of all such arguments, has a bearing upon the duties of life. 2For our aim in every matter of inquiry is to learn how the good and excellent man may find the appropriate course through it and the appropriate way of conducting himself in it. 3Let them say, then, either that the good man will not enter the contest of question and answer, or that, once he has entered, he will be at no pains to avoid conducting himself carelessly and at haphazard in question and answer; 4or else, if they accept neither of these alternatives, they must admit that some investigation should be made of those topics with which question and answer are principally concerned.
5For what is the professed object of reasoning? To state the true, to eliminate the false, to suspend judgement in doubtful cases. Is it enough, then, to learn this alone?—It is enough, says one.6—Is it, then, also enough for the man who wants to make no mistake in the use of money to be told the reason why you accept genuine drachmas and reject the counterfeit?—It is not enough.7 —What, then, must be added to this? Why, what else but the faculty that tests the genuine drachmas and the counterfeit and distinguishes between them? 8Wherefore, in reasoning also the spoken word is not enough, is it? On the contrary, is it not necessary to develop the power of testing the true and the false and the uncertain and of distinguishing between them?—It is necessary.— 9What else besides this is proposed in reasoning? Pray accept the consequence of what you have properly granted. 10Come, is it enough, then, in this case also merely to know that this particular thing is true? It is not enough, but one must learn in what way a thing follows as a consequence upon certain other things, and how sometimes one thing follows upon one, and at other times upon several conjointly. 11Is it not, then, necessary that a man should also acquire this power, if he is to acquit himself intelligently in argument, and is himself not only to prove each point when he tries to prove it, but also to follow the argument of those who are conducting a proof, and is not to be misled by men who quibble as though they were proving something? 12There has consequently arisen among us, and shown itself to be necessary, a science which deals with inferential arguments and with logical figures and trains men therein.
13But of course there are times when we have with sound reasoning granted the premisses, and the inference from them is so-and-so; and, in spite of its being false, it is none the less the inference. 14What, then, should I do? Accept the fallacy? And how is that possible? 15Well, should I say, "It was not sound reasoning for me to grant the premisses"? Nay, but this is not permissible either. Or, "This does not follow from what has been granted"? But that is not permissible, either. 16What, then, must be done in these circumstances? Is it not this, that the fact of having borrowed is not enough to prove that one is still in debt, but we must add the circumstance that one abides by the loan—that is, has not paid it—17and just so our having once granted the premisses is not enough to compel us to accept the inference, but we must abide by our acceptance of the premisses? 18And what is more, if the premisses remain until the end what they were when they were granted, there is every necessity for us to abide by our acceptance of them, and to allow the conclusion that has been drawn from them;... 19for from our point of view and to our way of thinking this inference does not now result from the premisses, since we have withdrawn from our previous assent to the premisses. 20It is necessary, therefore, to enquire into premisses of this kind and into such change and equivocal modification of them, whereby, at the very moment the question is put, or the answer made, or the deduction drawn, or at some other similar stage in the argument, the premisses take on modified meanings and give occasion to the unthinking to be disconcerted, if they do not see what follows in consequence. 21Why is it necessary? In order that in this matter we may not behave unsuitably, nor at haphazard, nor confusedly.
22And the same holds true of hypotheses and hypothetical arguments. For it is necessary at times to postulate some hypothesis as a sort of stepping-stone for the subsequent argument. 23Are we, therefore, to grant any and every hypothesis that is proposed, or not every one? And if not every one, what one? 24And when a man has granted an hypothesis, must he abide for ever by it and maintain it, or are there times when he should abandon it and accept only the consequences which follow from it without accepting those which are opposed to it?—Yes.25—But someone says, "If you once admit an hypothesis that involves a possibility, I will compel you to be drawn on to an impossibility." Shall the prudent man refuse to engage with this person, and avoid enquiry and discussion with him? 26Yet who but the prudent is capable of using argument and skilful in question and answer, and, by Zeus, proof against deceit and sophistic fallacies? 27But shall he argue, indeed, and then not take pains to avoid conducting himself recklessly and at haphazard in argument? And if he does not, how will he any longer be the sort of man we think he is? 28But without some such exercise and preparation in formal reasoning, how will he be able to maintain the continuity of the argument? 29Let them show that he will be able, and all these speculations become mere superfluity; they were absurd and inconsistent with our preconception of the good man.
30Why are we still indolent and easy-going and sluggish, seeking excuses whereby we may avoid toiling or even late hours, as we try to perfect our own reason?— 31If, then, I err in these matters, I have not murdered my own father, have I?—Slave, pray where was there in this case a father for you to murder? What, then, have you done, you ask? You have committed what was the only possible error in the matter. 32Indeed this is the very remark I made to Rufus when he censured me for not discovering the one omission in a certain syllogism. "Well," said I, "it isn't as bad as if I had burned down the Capitol." But he answered, "Slave, the omission here is the Capitol." 33Or are there no other errors than setting fire to the Capitol and murdering one's father? But to make a reckless and foolish and haphazard use of the external impressions that come to one, to fail to follow an argument, or demonstration, or sophism—in a word, to fail to see in question and answer what is consistent with one's position or inconsistent—is none of these things an error?
1 With the Stoics, whose sole standard of judgement in problems of conduct was the appeal to reason, the proper training of the reasoning faculties was an indispensable prerequisite to the good life. Three modes of sophistical reasoning are here differentiated. "Equivocal premisses" are those that contain ambiguities in terms which are intended to mean one thing at one step in the argument, another at another. " Hypothetical premisses" involve assumptions, or conditions. The last class proceeds by drawing unexpected conclusions from the answers to questions.