The view that the truth of a proposition consists in its being a member of some suitably defined body of other propositions: a body that is consistent, coherent, and possibly endowed with other virtues, provided these are not defined in terms of truth. The theory, though surprising at first sight, has two strengths: (i) we test beliefs for truth in the light of other beliefs, including perceptual beliefs, and (ii) we cannot step outside our own best system of belief, to see how well it is doing in terms of correspondence with the world. To many thinkers the weak point of pure coherence theories is that they fail to include a proper sense of the way in which actual systems of belief are sustained by persons with perceptual experience, impinged upon by their environment. For a pure coherence theorist, experience is only relevant as the source of perceptual beliefs, which take their place as part of the coherent or incoherent set. This seems not to do justice to our sense that experience plays a special role in controlling our systems of belief, but coherentists have contested the claim in various ways. See also correspondence theory of truth.