AbstractIn FW 372 Nietzsche distinguishes between “idealism” and “sensualism”. The ancient philosophers thought that the senses would lead “to some dangerous southern island”. This island refers undoubtedly to the rock from which the Sirens attempt to compel Odysseus. The aphorism could nevertheless contain another reference, i. e. to the island whose philosophical meaning relies exactly on the distinction between idealism and sensualism. I refer to the Island quoted from Heraclitus, fr. B 56 D.K., that Nietzsche borrows from Aristotle (fr. 76 Rose). FW 302 confirms in fact that Nietzsche is familiar with this text.