Logic in the Islamic Legacy: a General Overview

Concluding Remarks

We have seen that the Greek syllogism underwent a variety of modifications in the Medieval Islamic environment. The involvement of analogical reasoning with syllogistics was an attempt to aid the process of legal reasoning, but it was the a priori metaphysical assumptions which de marcate thinkers most forcefully. AI-Fiiriibi's successfully raised the strength of analogy to that of a first order syllogism thereby insisting that the 'il/a must exist along with a judgment in all inferences. Inevitably, al-Farabi's departure from the a priori interpretation of the Qur'an attracted much adversity from literalists. It is to al-Farabi that thinkers such as al-Ghazali and Ibn Taymiyya owe their whole point of departure.

In his article, "GhazaI'i's Attitude to the Secular Sciences and Logic", Michael Marmura has stated:

The matter of the syllogism involves the epistemological status of its premises; the form, the rules for valid inference. To take the formal aspect first, the philosopher's logic is the more comprehensive as it includes, for example, the Aristotelian figures which, prior to Ghazali, were not included in nazar. It also included a more precise formulation of analogical reasoning which, for example, Alfarabi reduced to the first Aristotelian figure and which, probably following him, Ghazali urged his fellow theologians to adopt.

AI-Ghazal'i could not deny, at least at the level of social and legal disputation, the auspicious utility of the syllogism, replete with its probable analogies. It is only at the metaphysical level (causality) where al-GhazaI'i becomes uncomfortable with the encroachment of the Greek tools (logic) upon the Muslim texts. If scriptures conflict with the "findings" of the syllogism, then (unlike with Hume and his aversion to religion) the Scriptures are to be assigned metaphorical readings. The dissonance produced by religion and logic is diffused, and the syllogism can remain a welcome addendum to the legal ambiguities pondered by the jurists.

With Ibn Taymiyya we saw that all legitimate definitions proceed from the Qur'an when legal and/or existential conceptions are being formed. His attack on causality and modal logic, employed mainly by philosophers (but also by theologians) places him in a-causal agnostic position where the explication of metaphysics is concerned. One could almost assume that, in relation to logic, analogy and syllogistic proofs, the words of David Hume could be supplanted into the pen of Ibn Taymiyya who resisted all such logical attempts at a definitive metaphysical reconstruction:

But can a conclusion, with any propriety, be transferred from parts to the whole? Does not the great disproportion bar all comparison and inference from observing the growth of a hair? Can we learn anything concerning the generation of a man? Would the manner of a leaf's blowing, even though perfectly known, afford us any instruction concerning the vegetation of a tree?

And elsewhere:

If we see a house, Cleanthes, we conclude, with the greatest certainty, that it had an architect or builder because this is precisely that species of effect which we have experienced to proceed from that species of cause. But surely you will not affirm that the universe bears such a resemblance to a house that we can with the same certainty infer a similar cause, or that the analogy is here entire and perfect. The dissimilitude is so striking that the utmost you can here pretend to is.

Ibn Taymiyya would undoubtedly agree with much of this, but would reject Hume's skeptical ethos by maintaining revealed Qur'anic foundations. Indeed, he would take literally Hume's ambiguous statement, "Let us fix our attention out of ourselves as much as possible: Let us chase our imagination to the heavens, or to the utmost limits of the universe". However, it would not be adverse to state that Ibn Taymiyya was also a skeptic, "a sceptic who was saved by religion", but nevertheless a skeptic. Thus his bid to question identity goes only so far. In the face of outright skepticism, then, comes outright faith.

There remained the task of determining the proper limits and applications of syllogism so as to define and categorize the termqiyiis (a method of inference).

These discussions were the result of the theologically motivated defense of the concept of divine omnipotence that solely actuated existence, events, miracles and their causal links. It follows, then, that Theologians did not accept the doctrine of natural causation where phenomenal acts proceeded from a thing's quiddity. In their view Causal efficacy resided solely with God's divine will and contingent atoms and accidents were created ex nihilo. Thus, no causal uniformity in nature was inherently possible

For Muslims Greek logic was initially a means to defend metaphysical doctrines but the scope of logic was expanded to jurisprudence and language. All of this was attempted under the questionable notion that logic could remain doctrinally neutral and, at the same time, could be used to the advantage and defense of religion.  Eventually, the supposed neutrality of logic was vehemently called into question.

The use of analogy formed part of the Qur'anically derived juridical system. Complications arose once the syllogism was introduced. Suddenly, metaphysical assumptions were questioned; this gave rise to the ambiguous relationship between analogy and the syllogism especially when attempting to define qiyas. A variety of arguments surrounds this term and its translation into "analogy": "Qiyiis thus cannot be given the fixed definition of analogy. Instead, it should be regarded as a relative term whose definition and structure vary from one jurist to another." Qiyiis, denotes a way of inferring something from another, and is derived from the logical sciences which embrace both the syllogism and analogy. The concern here is to determine the central method by which juridical qiyas was endowed with "a wider definition as to include formal arguments".