This book sets out to answer the question: what happened to Islam to make it such an enormous problem today? The author’s strategy is to explain what happened so that we can go on to make a correct diagnosis. Islam has been voided of reason (dehellenized) and as a result turned into an ideology: Islamism. “Islamism is grounded in a spiritual pathology based upon a theological deformation that has produced a dysfunctional culture. Therefore the problem must be addressed at the level at which it exists.”
Roger Scruton says in the Foreword: “In his celebrated treatise The Incoherence of the Philosophers, al-Ghazali set out to show that reason, as enshrined in the writings of Plato, Aristotle, and their followers, leads to nothing save darkness and contradiction, and that the only light that shines in the mind of man is the light of revelation.” The result was incoherence. If you drive out good philosophy, your only alternative is bad philosophy. If you decide that God is not on the side of reason, then you have to be irrational.
The spiritual pathology is to ratchet up a high view of God by degrading man excessively. No man can think. Man is not made to think, but to obey. Man must submit to God even by refusing to reason. The theological deformation is Voluntarism and philosophical occasionalism. There is no such thing as cause and effect: things follow because God arbitrarily wills them at every moment. We cannot know him, we cannot understand him, we can only submit. The dysfunctional culture is one in which power and authority are one, all inquiry into anything is discouraged, and the resulting degradation of life is resented. It can’t be blamed on God, it must be blamed on incomplete submission.
To me, al-Ghazali sounds like presuppositionalism, which is why I read the book. It is far more interesting than reading stuff by presuppositionalists.