Conclusion

Deduction (istintāj), then, is the outcome of induction (istiqrāʼ); for by induction we judge the general rule and are guided to the natural law (al-nāmūs al-ṭabīʻī), while by deduction we judge of individuals

Conclusion

Errors often arise in discussions and in disputes for want of attention. We have already drawn notice to most of their kinds in what has gone before: such as passing from the known to the unknown; and setting up the proof (burhān) of a thing by a proposition (qaḍīyah) whose soundness depends upon the soundness of the first; or defining a thing by another thing which, were the question put about it, would be defined by the first — and this is called circularity (al-dawr). And such as inferring the material by analogy with the non-material, or the reverse. And such as passing from what is true in some respects to what is true in all respects. And such as drawing out a universal matter from a number of particular matters, which is incomplete induction (al-istiqrāʼ al-nāqiṣ). And such as making what is not a cause a cause, or supposing the soundness of what is unsound. And such as answering about the unknown with what is itself unknown as well, or defining a thing by its synonyms, which is begging the question (al-muṣādarah). And such as answering with what has no connection with the question, which is wrangling (al-mushāghabah). And this kind of fallacy (mughālaṭah) is often employed by certain shameless orators in the hope of drawing their hearers over to themselves, and that by adducing what is granted and self-evident (badīhī) and what works upon the emotions and upon religious or communal feelings and the like, so as to win approval, and so that the hearer may forget the original subject and come to suppose that his adversary had been denying that, and so turn against him. And you may find many examples of this in the speeches of the men of politics of the backward parties — albeit that this method, though it be exceedingly faulty, politics permits lying with a view to obtaining the result required

Among the simple fallacies is what comes about through the use of significations that are shared (mushtarakah), or resembling, or absolutely obscure — as when a speaker says: the eye (ʻayn) may have drowsiness creep into it, and this is an ʻayn (pointing to a spring of water), therefore this ʻayn may have drowsiness creep into it. And his saying: light gleams and shines in the darkness, and the intellect (ʻaql) is light, so the intellect gleams and shines in the darkness. And his saying: some men are learned and some men are rich, so some of the learned are rich. The error in the first two examples is plain; in the third it is the possibility that the first “some” is other than the second “some” — and once possibility (iḥtimāl) comes upon the indicator (dalīl), the inference is thereby void

As the poet said:

And thought may go corrupt in the state it is in — so that it makes you fancy the pearl to be a drop of the night dew

And whenever a man has made himself firm in what we have mentioned concerning the primary truths (al-awwalīyāt), and attends, in the application of the syllogisms (al-aqyisah), to what we have mentioned of the rules, he is safe from error. Here is an example plainer than this, namely: some stones are white, and some stones are black. It cannot follow from this that some white thing is black. Errors enter, and are palmed off upon a man, for the most part only when the syllogisms interlock and run on in a chain, or when his thought is wearied and his attention grows weak

Most authors have indeed brought the table (al-jadwal), rhetoric (khaṭābah), and poetry — indeed, even fallacy — into logic. But since these yield no certainty (yaqīn), and are arts (ṣināʻāt) proper to themselves and standing on their own, I have passed them over in this treatise

Completed on 4 Muḥarram of the year 1325, and on 17 Shubāṭ, by the Frankish reckoning (ifranjī), of the year 1907

Dimashq al-Shām: Muḥammad Salīm al-Jazāʼirī al-Ḥasanī