 Proponents of the Kalām tradition, such as al-Bāqillānī (950–1013) and al-Ghazālī (1058–1111), had a two-stage critique. First, anticipating Hume by at least 700 years, these thinkers noted that observation alone could not distinguish between causal connections and mere constant conjunctions. (A contemporary example often found in statistic classes is that the summer sun’s heat seems to be causally connected with ice cream’s melting, whereas eating ice cream is only constantly conjoined, at least in the US, with an increase in violent crimes.) Observation alone, these thinkers warn us, cannot determine, for example, whether the cotton’s burning, which follows upon placing fire in the cotton, or intoxication, which follows upon imbibing alcohol, is causally connected with the natures of fire and alcohol respectively, or whether these sets of events are merely constantly conjoined. Indeed the concurrence of two events may be a result of God’s habit or custom (ʿāda or sunna) of causing the one event together with the other. While one might think that appealing to God to explain the various mundane events that we constantly observe around us is extravagant, Kalām thinkers countered that it was in fact the philosophers who are ontologically profligate, for the theologians assume only one class of causes, namely, willful agent(s), whereas the philosophers are committed to two ontologically distinct classes of causes, if not more. This point leads to the second stage of the Kalām critique of natures. God’s (omnipotent) causal power extends to every actual or even possible event. God’s causal power is either sufficient to produce these effects or it is not. If God’s power is not sufficient, then either the deity needs the added “boost” of natural powers, or it needs natures as a tool or instrument, etc.  This later position flirts with impiety. If, however, God’s causal power is sufficient to produce every effect and there are also natures, functioning as internal causes, every event is over-determined. Indeed it is not clear at all what causal role natures have to play. A principle of parsimony, so the Kalām critique concludes, suggests that natures be jettisoned and one reserve all causal power to God alone. While Avicenna addresses the issue of the existence of natures and offers up a demonstration for their existence in the Metaphysics (4.2, 9.2 &amp; 9.5; also see Dadikhuda 2019), he also notes that the science of physics is not the proper place to undertake such an enterprise. That is because the existence of a science’s subject matter, Avicenna notes following Aristotle, is never demonstrated within that very science itself but only in a higher science. 