The Divisions of the Philosophical Sciences (Part Two: Logical Sciences)

Excerpt from al-Ghazali's Deliverance from Error:

Nothing in the logical sciences has anything to do with religion by way of negation and affirmation. On the contrary, they are the study of the methods of proofs, of syllogisms, of the conditions governing the premises of apodeictic demonstration, of how these premises are to be combined, of the requisites for a sound definition, and how the latter is to be drawn up, Knowledge is either a concept, and the way to know it is the definition, or the assent, and the way to know it is the apodeictic demonstration. There is nothing in this which must be rejected. One the contrary, it is the sort of thing mentioned by the mutakallimun and the partisans of reasoning in connection with the proofs they use. The philosophers differ from them only in modes of expression and technical terms and in a greater refinement in definitions and subdivisions. Their manner of discoursing on such things is exemplified by their saying: "if it is certain that every A is B, then it necessarily follows that some B is A"- for instance: if it is certain that every man is an animal, then it follows necessarily that some animal is a man. This they express saying that a universal affirmative proposition is convertible to a particular affirmative proposition.

What has this to do with the important truths of our religion, that it should call for rejection and denial? When it is rejected, the only effect of such a rejection in the minds of logicians is a low opinion of the rejecter's intelligence, and, what is worse, of his religion, which, he claims, rests on such rejection. To be sure, the philosophers themselves are guilty of a kind of injustice in the case of this science of logic. This is that in logic they bring together, for apodeictic demonstration, conditions known to lead undoubtedly to sure and certain knowledge. But when, in metaphysics, they finally come to discuss questions touching on religion, they cannot satisfy those conditions, but rather are extremely slipshod in applying them. Moreover, logic may be studied by one who will think it a fine thing and regard it is very clear. Consequently he will think that the instances of unbelief related of the philosophers are backed up by the demonstrations such as those set forth in logic. Therefore he will rush into unbelief even before reaching the metaphysical sciences. Hence this evil may befall the student of logic.