will confirm the sharing: "And every reasonable [universal] expectation depends on resemblance of [generic] circumstances, together with our tendency to expect similar causes to have similar effects." "The notion of a kind and the notion of similarity or resemblance seem to be variants or adaptations of a single [universal] notion. Similarity is immediately definable in terms of kind; for things are similar when they are two of a kind."

Quine posited an intuitive human capacity to recognize criteria for judging degrees of similarity among