 Aristotle’s comments do not sound as if they were based on first-hand knowledge of Thales’ views, and the doxographical reports say that Thales did not write a book. Yet Aristotle is confident that Thales belongs, even if honorifically, to that group of thinkers that he calls “inquirers into nature” and distinguishes him from earlier poetical “myth-makers.” In Book I of Metaphysics, Aristotle claims that the earliest of these, among whom he places the Milesians, explained things only in terms of their matter (Met. I.3 983b6–18). This claim is anachronistic in that it presupposes Aristotle’s own novel view that a complete explanation must encompass four factors: what he called the material, efficient, formal, and final causes. Yet there is something in what Aristotle says. Aristotle links Thales’ claim that the world rests on water with the view that water was the archē, or fundamental principle, and he adds that “that from which they come to be is a principle of all things” (983b24–25; DK 11A12/LM 5D3, R9). He suggests that Thales chose water because of its fundamental role in coming-to-be, nutrition, and growth, and claims that water is the origin of the nature of moist things. 