It seems to me that the "tricky" word here is knowledge.
We have that, for Aristotle :
The subject of the Posterior Analytics is epistêmê. This is one of several Greek words that can reasonably be translated “knowledge”, but Aristotle is concerned only with knowledge of a certain type (as will be explained below). There is a long tradition of translating epistêmê in this technical sense as science, and I shall follow that tradition here. However, readers should not be misled by the use of that word. In particular, Aristotle’s theory of science cannot be considered a counterpart to modern philosophy of science, at least not without substantial qualifications.
We have (scientific) knowledge, according to Aristotle, when we know:
the cause why the thing is, that it is the cause of this, and that this cannot be otherwise. (Posterior Analytics,I.2)
This implies two strong conditions on what can be the object of scientific knowledge:
i.Only what is necessarily the case can be known scientifically
ii.Scientific knowledge is knowledge of causes
[...] Aristotle clearly thinks that science is knowledge of causes and that in a demonstration, knowledge of the premises is what brings about knowledge of the conclusion.
If we equate knowledge with epistêmê, we have that it is hard to speak of "knowledge of causes" in the case of a "bare particular" (like a pebble).
Of course, a more "correct" answer has to take care of Al-Ghazali use of "knowledge" and of his interpretation of Aristotle's theories :
Al-Ghazâlî describes the Incoherence of the Philosophers (Tahâfut al-falâsifa) as a “refutation” of the philosophical movement (Ghazâlî 1959a, 18 = 2000b, 61), and this has contributed to the erroneous assumption that he opposed Aristotelianism and rejected its teachings. His response to falsafa [the Arabic tradition of Aristotelian philosophy, from Greek: philosophía] was far more complex and allowed him to adopt many of its teachings. The falâsifa are convinced, al-Ghazâlî complains at the beginning of the Incoherence, that their way of knowing by “demonstrative proof” (burhân) is superior to theological knowledge drawn from revelation and its rational interpretation.