Abū Ḥāmid al-Ghazālī, answered from the texts and cited to the page.
The title names the aim precisely. Tahāfut — incoherence, collapse, the headlong rush into disaster — is what I found when I examined the philosophers' claims to have established, by conclusive demonstration, the true nature of things.1 The book is not a work of construction. I said this plainly in the text itself: I entered not as one who introduces and builds, but as one who destroys and objects.2
That is the office the moment required. The philosophers — and I mean above all Aristotle, whose views their tradition had refined and systematized — claimed a kind of certainty they had not earned. My purpose was to make that impotence visible. Twenty problems are taken up in sequence.3 The first four bear on the eternity of the world; others concern whether God knows particulars, whether the soul perishes, whether the disruption of the habitual course of nature is possible.
On seventeen of these I show that the philosophers have failed to demonstrate what they assert — they are in error, but the error is internal to rational inquiry and does not cross a categorical boundary. Three touch what revelation states plainly, and there the judgement is of a different kind. What the book is for is as important as what it tears down.
Once the claim to conclusive demonstration collapses, a space opens. There are those who hold that the realities of divine matters are not reached by rational reflection alone — that the lawgiver's instruction to think on God's creation rather than God's essence is not an evasion but a limit built into the instrument itself.4 The philosophers disapprove of such people, attributing to them mere ignorance of syllogistic method.
But if the philosophers' own demonstrations are incoherent, that disapproval loses its ground entirely. The argument is therefore a defence before it is an attack: a defence of prophecy, of miracle, of the path that reason can point toward but cannot itself walk.
A common meaning is 'collapse,' or 'collapsing,' sometimes with the nuance of rushing headlong and crowding to fall into disaster, into hellfire.The Incoherence of the Philosophers, pp. 25–26
We did not plunge into this book in the manner of those who introduce [what is constructive], but in the manner of those who are destroyers and objectors. For this reason we have named the book The Incoherence of the Philosophers, not The Introduction to Truth.The Incoherence of the Philosophers, pp. 241–242
The first problem: [On] refuting their doctrine of the world's preeternity... The twentieth:" [listing twenty discussions in sequence]The Incoherence of the Philosophers, pp. 49–51
What is intended is to show your impotence in your claim of knowing the true nature of things through conclusive demonstrations, and to shed doubt on your claims. Once your impotence becomes manifest, then [one must point out that] there are among people those who hold that the realities of divine matters are not attained through rational reflection.The Incoherence of the Philosophers, pp. 241–242