              Aristotle’s own preferred alternative, that there are first principles of the sciences graspable by those willing to engage in assiduous study, has caused consternation in many of his readers.   In Posterior Analytics ii 19, he describes the process by which knowers move from perception to memory, and from memory to experience (empeiria)—which is a fairly technical term in this connection, reflecting the point at which a single universal comes to take root in the mind—and finally from experience to a grasp of first principles.   This final intellectual state Aristotle characterizes as a kind of unmediated intellectual apprehension (nous) of first principles (APo. 100a10–b6).