The source relies on a common error, the source of which is explained
here
The error:
His Incoherence of the Philosophers attacked philosophy on 20 counts of heresy. These included the idea that nature had its own, internally-consistent laws and ways of operating – this was heretical because only God is truly independent, and nature must be dependent on God...
The Asharis also denied causality, or the principle of cause and effect, even though their position negates free will and personal responsibility. If I were to punch you in the face, I could argue that God and his angels had actually broken your nose: it was purely a coincidence that my fist was nearby, and any imagined connection between my punch and your injury was just an illusion!
AG believed we should assume consistency in nature, but it is not impossible that God intervenes, hence miracles.
I have already quoted AGs views that clearly assume predictability in nature, if you would prefer a secondary source (from a Professor of Philosophy, who specialises in Islamic Philosophy and thus actually understands the context):
Thus al-Ghazâlî himself raises the question of why miracles do not prevent our knowledge of the empirical world, admitting that if they did, a man who left a book in his home would have to say, 'I do not know what is in the house now, and the extent of what I know is only that I left a book in the house, and perhaps now it is a horse.' (10) Al-Ghazâlî's response to the objection is most intriguing: he suggests that God continually creates in us the knowledge that He will not perform these miracles. Thus the source of a man's knowledge that, say, his book is still in the house, is God Himself. Indeed, al-Ghazâlî seems to be contrasting the so-called 'knowledge' of experience, which only leads to the habit of expecting given natures to cause given effects, with a certain knowledge created in us by God...
al-Ghazâlî goes on to say, in essence, that natural causes can be regarded as causes if we invoke a weaker notion of causality. He admits that a natural cause has a nature which gives rise to certain effects: fire, for instance, has a nature such that it burns whatever is in contact with it. But this does not mean that fire is a necessary cause, in the sense that the existence of fire in contact with cotton logically entails the existence of burning cotton. The nature of fire itself, says al-Ghazâlî, derives from God, and God chooses whether or not this nature will give rise to its normal effect or not. On al-Ghazâlî's view, natural causes are only contingently causes -- their effects only proceed if the true Agent who gave them their natures wishes it.
20th WCP: Al-Ghazâlî, Causality, and Knowledge
Another obvious error. What your "expert" claims represents "AG's triumph":
Al-Ghazali's triumph in the Islamic world led to a deepening gulf between religion and science. A couple of examples from 15th-century traditionalist scholars will illustrate this. Ibn Hajar, a master of hadith-commentary, queried the Muslim astronomers who explained that solar eclipses were caused by the moon blocking the sun: "How can this be, when you yourselves claim that the sun is much bigger than the moon? And the Egyptian scholar Suyuti wrote in his Qur'an-commentary, "The religious authorities hold that the earth is flat, in opposition to the astronomers who hold that it is spherical, although this is not a major principle of religion."
What AG said:
Again, the eye sees a star and believes it as large as a piece of gold, but mathematical
calculations prove, on the contrary, that it is larger than the earth. These notions, and all others
which the senses declare true, are subsequently contradicted and convicted of falsity in an
irrefragable manner by the verdict of reason...
The second evil comes from the sincere but ignorant Muslims who thinks the best
way to defend religion is by rejecting all the exact sciences. Accusing their
professors of being astray, he rejects their theories of the eclipses of the sun and
moon, and condemns them in the name of religion. These accusations are carried
far and wide, they reach the ears of the philosopher who knows that these theories
rest on infallible proofs; far from losing confidence in them, he believes, on the
contrary, that Islam has ignorance and the denial of scientific proofs for its basis,
and his devotion to philosophy increases with his hatred to religion.
It is therefore a great injury to religion to suppose that the defense of Islam
involves the condemnation of the exact sciences. The religious law contains
nothing which approves them or condemns them, and in their turn they make no
attack on religion.
So the best evidence he can offer that AG made people anti-science comes from 4 centuries later and is the exact opposite of what AG argued...
So now I think we can conclude that these claims rest on a misunderstanding/misrepresentation of AGs arguments, or at least that no one in this thread has presented any arguments that
do not rest on such misunderstanding/misrepresentation.
Occasionalism wasn't even remotely new, it was the standard position of large percentage of Muslims throughout the Golden Age.
Given that we have numerous very clear and obvious reasons for social decline, such as warfare, conquest, economic decline and changing patterns of global trade, it seems quite clear that it would be irrational to assume AG played any significant role unless any evidence can be presented to illustrate this.
You're welcome.