 Atoms in Islamic philosophy were typically defined by the occupation of space and the exclusion of other bodies; by their ability to receive accidents; and by their ability to be perceived by the senses of sight and touch, presumably in sufficiently large aggregates. The assertion of an entailment between materiality and occupying space was apparently directed against the Peripatetic notion of matter and the Aristotelian notion of natural place (Dhanani 1994, 88–89). The spatial extendedness of atoms was also linked to the notion that atoms served as a unit for measuring extension. Because spherical atoms packed together would leave a space that is smaller than the atom—which would be impossible if atoms represented the smallest possible magnitude—atoms were said to be cubic (Dhanani 1994, 115). Atoms were thought to adhere to one another without the physical ‘hooks’ proposed by Democritus; even so, it proved difficult to avoid ascribing subatomic parts to atoms.