Tahafut_al-Tahafut-transl-Engl-van-den-Bergh

arguments in the following form: How can man’s identity be attributed to
body with all its accidents? For bodies are continually in dissolution and
nutrition replaces what is dissolved, so that when we see a child, after
separation from its mother’s womb, fall ill a few times, become thin and
then fat again, and grow up, we may safely say that after forty years no
particle remains of what there was when its mother was delivered of it.
Indeed, the child began its existence out of parts of the sperm alone, but
nothing of the particles of the sperm remains in it; no, all this is dissolved
and has changed into something else and then this body has become
another. Still we say that the identical man remains and his notions remain
with him from the beginning of his youth although all bodily parts have
changed, and this shows that the soul has an existence outside the body
and that the body is its organ. Now the first part of this argument, that all
things are in a state of flux and that of the bodily life of man no part
remains identical, is textually found in Montaigne’s Apologv of Raymond
de Sebond. Montaigne has taken it from Plutarch, and the Arabic
philosophers may have borrowed it from the same source from which
Plutarch has taken it. The argument of the philosophers that matter is
evanescent, but the soul a stable identity, which is also given by the
Christian philosopher Nemesius in his De natura hominis (a book
translated into Arabic), who ascribes it to Ammonius Saccas and
Numenius, is basically Platonic and Neoplatonic, and strangely enough,
although he refutes it here, it is adduced by Ghazali himself in his
Vivification of Theology. Socrates says in the Platonic dialogue Cratylus:
‘Can we truly say that there is knowledge, Cratylus, if all things are
continually changing and nothing remains? For knowledge cannot
continue unless it remains and keeps its identity. But if knowledge
changes its very essence, it will lose at once its identity and there will be
no knowledge.’ Plotinus (Enn. iv. 7. 3) argues that matter, in its continual
changing, cannot explain the identity of the soul. And he says in a
beautiful passage (Enn. iv. 7. 10) the idea of which Avicenna has copied:
‘One should contemplate the nature of everything in its purity, since
what is added is ever an obstacle to its knowledge. Contemplate
therefore the soul in its abstraction or rather let him who makes this
abstraction contemplate himself in this state and he will know that he
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