 Despite the fact that commentators often appeal to E1ax4, the meaning of this important axiom is far from clear. There are two main interpretive problems (leaving aside the question of what sorts of causes, out of the rich panoply envisioned by the Aristotelians, Spinoza might allow in his metaphysics). The first problem concerns the kind of cognition at stake in E1ax4. Some readers (e.g. Bennett 1984; Gueroult 1969) have proposed that the axiom governs adequate cognition alone. So understood, the axiom expresses a version of the traditional view that truly “scientific” knowledge requires a knowledge of causes – the knowledge why something happened, not merely that it happened. But, as Margaret Wilson points out (1999: ch.10), this restricted reading of the scope of the axiom can’t be correct, since in Spinoza’s view even inadequate ideas formed in sense experience “involve” their causes. (For example, the inadequate knowledge I have of any bodily change “involves” the inadequate knowledge of its external cause [E2ax1’, E2p25, E2p28].)