General, discursively structured criticism of the way in which humans conceive and imagine the gods reaches back to the very beginnings of systematic Western philosophy. We have fragments of poems by Xenophanes written in the second half of the sixth century bc that contain a remarkably modern-sounding analysis and rejection of anthropomorphism (cf. DE, 4, 255, n. 6). Humans, he notes, think that the gods have human shape, but each race of men attributes to them its class="EmphasisTypeItalic ">own characteristic physical features: African gods have dark skin and snub noses; Thracian gods have blue eyes and red hair. If horses made statues of gods, their gods would be equiform, so the fact that all humans think the gods have human shape is a fact about humans, not about the divine. What is historically perhaps most notable about this is that Xenophanes in presenting his case does not appeal to any form of esoteric lore, to intuition, revelation, or the inspiration of the muses, but merely to comparative, empirical observation and to everyday forms of human reasoning. It is by virtue of this method of enquiry, more than of the particular results to which he comes, that Xenophanes can count as an early representative of the general, pan-European movement called by members of the early Frankfurt School the "Enlightenment".