Al-Ghazali's relationship with philosophy is subtle and
complicated. The philosophy represented by al-Farabi and Ibn Sina (Avicenna) is,
for al-Ghazali, not simply an object of criticism but also an important
component of his own learning. He studied philosophy intensively while in
Baghdad, composing Maqasid
al-falasifa (The Intentions of the Philosophers), and then
criticizing it in his Tahafut
al-falasifa (The Incoherence of the Philosophers). The Maqasid
is a precise summary of philosophy (it is said to be an Arabic version of Ibn
Sina's Persian Danashnamah-yi ala'i (Book of Scientific Knowledge)
though a close comparative study of the two works has yet to be made). In the
medieval Latin world, however, the content of the Maqasid
was believed to be al-Ghazali's own thought, due to textual defects in the
Latin manuscripts. As a result, the image of the 'Philosopher Algazel' was
created. It was only in the middle of the nineteenth century that Munk
corrected this mistake by making use of the complete manuscripts of the Hebrew
translation. More works by al-Ghazali began to be published thereafter, but
some contained philosophical ideas he himself had once rejected. This made
al-Ghazali's relation to philosophy once again obscure. Did he turn back to
philosophy late in life? Was he a secret philosopher? From the middle of the
twentieth century there were several attempts to verify al-Ghazali's authentic
works through textual criticism, and as a result of these works the image of
al-Ghazali as an orthodox Ash'arite theologian began to prevail. The new trend
in the study of al-Ghazali is to re-examine his relation to philosophy and to
traditional Ash'arism while at the same time recognizing his basic distance
from philosophy.
Al-Ghazali composed three works on Aristotelian logic, Mi'yar al-'ilm
(The Standard Measure of Knowledge), Mihakk al-nazar
fi'l-mantiq (The Touchstone of Proof in Logic) and al-Qistas
al-mustaqim (The Just Balance). The first two were written
immediately after the Tahafut
'in order to help understanding of the latter', and the third was composed
after his retirement. He also gave a detailed account of logic in the long
introduction of his writing on legal theory, al-Mustasfa min
'ilm al-usul (The Essentials of Islamic Legal Theory). Al-Ghazali's
great interest in logic is unusual, particularly when most Muslim theologians
were antagonistic to it, and can be attributed not only to the usefulness of
logic in refuting heretical views (al-Qistas
is also a work of refutation of the Isma'ilis), but also to his being
fascinated by the exactness of logic and its effectiveness for reconstructing
the religious sciences on a solid basis.
There is a fundamental disparity between al-Ghazali's
theological view and the Neoplatonic-Aristotelian philosophy of emanationism.
Al-Ghazali epitomizes this view in twenty points, three of which are especially
prominent: (1) the philosophers' belief in the eternity of the world, (2) their
doctrine that God does not know particulars, and (3) their denial of the
resurrection of bodies. These theses are ultimately reducible to differing
conceptions of God and ontology. Interestingly, al-Ghazali's criticism of
philosophy is philosophical rather than theological, and is undertaken from the
viewpoint of reason.
First, as for the eternity of the world, the philosophers claim
that the emanation of the First Intellect and other beings is the result of the
necessary causality of God's essence, and therefore the world as a whole is
concomitant and coeternal with his existence (see Creation and conservation, religious
doctrine of). Suppose, say the philosophers, that God created the
world at a certain moment in time; that would presuppose a change in God, which
is impossible. Further, since each moment of time is perfectly similar, it is
impossible, even for God, to choose a particular moment in time for creation.
Al-Ghazali retorts that God's creation of the world was decided in the eternal
past, and therefore it does not mean any change in God; indeed, time itself is
God's creation (this is also an argument based on the Aristotelian concept of
time as a function of change). Even though the current of time is similar in
every part, it is the nature of God's will to choose a particular out of
similar ones.
Second, the philosophers deny God's knowledge of particulars or
confine it to his self-knowledge, since they suppose that to connect God's
knowledge with particulars means a change and plurality in God's essence.
Al-Ghazali denies this. If God has complete knowledge of a person from birth to
death, there will be no change in God's eternal knowledge, even though the
person's life changes from moment to moment.
Third, the philosophers deny bodily resurrection, asserting that
'the resurrection' means in reality the separation of the soul from the body
after death. Al-Ghazali criticizes this argument, and also attacks the theory
of causality presupposed in the philosophers' arguments (see Causality and necessity in Islamic
thought). The so-called necessity of causality is, says al-Ghazali,
simply based on the mere fact that an event A has so far occurred concomitantly
with an event B. There is no guarantee of the continuation of that relationship
in the future, since the connection of A and B lacks logical necessity. In
fact, according to Ash'arite atomistic occasionalism, the direct cause of both
A and B is God; God simply creates A when he creates B. Thus theoretically he
can change his custom (sunna, 'ada) at any moment, and resurrect
the dead: in fact, this is 'a second creation'.
Al-Ghazali
thus claims that the philosophers' arguments cannot survive philosophical
criticism, and Aristotelian logic served as a powerful weapon for this purpose.
However, if the conclusions of philosophy cannot be proved by reason, is not
the same true of theological principles or the teachings of revelation? How
then can the truth of the latter be demonstrated? Herein lies the force of
al-Ghazali's critique of reason.