 When Ryle became a young don in the 1920s, philosophers could no longer “pretend that philosophy differed from physics, chemistry and biology by studying mental as opposed to material phenomena” (1971b, vii). Although the turn away from psychologism was laudable, philosophers succumbed instead to what Ryle considered to be a regrettable temptation to look for Objects which were neither mental nor material. Such objects were to be for philosophy what beetles and butterflies are for entomology: