Logic in the Islamic Legacy: a General Overview

Logic and Language

Al-farabi explains how logic, grammar and language relate to each other:

And this art (of logic) is analogous to the art of grammar, in that the relation of the art of logic to the intellect and the intelligibles is like the relation of the art of grammar to language and expressions. That is, to every rule for expressions which the science of grammar provides us, there is a corresponding [rule] for intelligibles which the science of logic provides us (Ihsa' al-'ulum, in Amin 1968: 68).

al-Farabi argues that logic and grammar both have some legitimate interest in language, but whereas grammatical rules primarily govern the use of language, logical rules primarily govern the use of intelligibles.

More precisely, al-Farabi explains that although grammar and logic share a mutual concern with expressions, grammar provides rules that govern the correct use of expressions in a given language, but logic provides rules that govern the use of any language whatsoever in so far as it signifies intelligibles. Thus, logic will have some of the characteristics of a universal grammar, attending to the common features of all languages that reflect their underlying intelligible content. Some linguistic features will be studied in both logic and grammar, but logic will study them as they are common, and grammar in so far as they are idiomatic. On the basis of this comparison with grammar, then, al-Farabi is able to complete his characterization of the subject matter of logic as follows: 'The subject-matters of logic are the things for which logic provides the rules, namely, intelligibles in so far as they are signified by expressions, and expressions in so far as they signify intelligibles' (Ihsa' al-'ulum, in Amin 1968: 74).

Alfarabi adds:

Logic shares something with grammar in that it provides rules for expressions, yet it differs in that grammar only provides rules specific to the expressions of a given community, whereas the science of logic provides common rules that are general for the expressions of every community. This is to say - logic is something of a universal grammar or, more strictly, providing a universal grammar is one of the tasks of logic.

Avicenna recognizes and attempts to deal with the close nexus between language and thought:

Were it possible for logic to be learned through pure cogitation, so that meanings alone would be observed in it, then this would suffice. And if it were possible for the disputant to disclose what is in his soul through some other device, then he would dispense entirely with its expression. But since it is necessary to employ expressions, and especially as it is not possible for the reasoning faculty to arrange meanings without imagining the expressions corresponding to them (reasoning being rather a dialogue with oneself by means of imagined expressions), it follows that expressions have various modes (ahwâl) on account of which the modes of the meanings corresponding to them in the soul vary so as to acquire qualifications (ahkâm ) which would not have existed without the expressions. It is for this reason that the art of logic must be concerned in part with investigating the modes of expressions… But there is no value in the doctrine of those who say that the subject matter of logic is to investigate expressions in so far as

they indicate meanings…but rather the matter should be understood in the way we described.

Ibn Sina criticized attempts to introduce linguistic concerns into the subject matter of logic. In al-Madkhal, Ibn Sina labels as 'stupid' those who say that 'the subject matter of logic is speculation concerning expressions in so far as they signify meanings (ma'ani)'. However, Ibn Sina does not deny that the logician is sometimes or even often required to consider linguistic matters; his objection is to the inclusion of language as an essential constituent of the subject matter of logic. The logician is only incidentally concerned with language because of the constraints of human thought and the practical exigencies of learning and communication. 'if logic could be learned through pure thought so that meanings alone could be attended to in it, then it would dispense entirely with expressions'; but since this is not in fact possible, 'the art of logic is compelled to have some of its parts come to consider the states of expressions' (al-Madhkal, in Anawati et al. 1952: 22-3). For Ibn Sina, then, logic is a purely rational art whose purpose is entirely captured by its goal of leading the mind from the known to the unknown; only accidentally and secondarily can it be considered a linguistic art.

As Sabra says, Avicenna seems to hold that “the properties constituting the subject matter of logic would be inconceivable without the exercise of a particular function of language” (Sabra (1980) 764).

However, Ibn Sina and al-Farabi were concerned to distinguish logic from grammar as many Arabic grammarians - whose linguistic theories were developed to a high degree of complexity and sophistication - were contemptuous of the philosophers for importing Greek logic, which they saw as a foreign linguistic tradition, into the Arabic milieu. This attitude toward Greek logic is epitomized in a famous debate reported to have taken place in Baghdad in 932 between the grammarian Abu Sa'id al-Sirafi and Abu Bishr Matta, a Syriac Christian who translated some of Aristotle's works into Arabic and is purported to have been one of al-Farabi's teachers. Abû Bishr argued that speakers of Arabic need to learn Greek logic. For him Logic comes ahead of Grammar:

"The logician has no need of grammar, whereas the grammarian does need logic. For logic enquires into the meaning, whereas grammar enquires into the expression. If, therefore, the logician deals with the expression, it is accidental, and it is likewise accidental if the grammarian deals with the meaning. Now, the meaning is more exalted than the expression, and the expression humbler than the meaning".

The extant account of the debate is heavily biased towards al-Sirafi, who attacks logical formalism and denies the ability of logic to act as a measure of reasoning over and above the innate capacities of the intellect itself. His principal claims are that philosophical logic is nothing but Greek grammar warmed over, that it is inextricably tied to the idiom of the Greek language and that it has nothing to offer speakers of another language such as Arabic.

Yahya ibn 'Adi, makes his case for the independence of logic from grammar based upon the differences between the grammar of a particular nation and the universal science of logic. He argues that the subject matter of grammar is mere expressions (al-alfaz ), which it studies from the limited

perspective of their correct articulation and vocalization according to Arabic conventions. The grammarian is especially concerned with language as an oral phenomenon; the logician alone is properly concerned with 'expressions in so far as they signify meanings' (al-alfaz al-dalla 'ala al-ma'ani ) (Maqala fi tabyin, in Endress 1978: 188). To support this claim, Yahya points out that changing grammatical inflections do not affect the basic signification of a word: if in one sentence a word occurs in the nominative case, with the appropriate vocalization, its signification remains unchanged when it is used in another sentence in the accusative case and with a different vocal ending.