There is no one kind of thing that we 'perceive' but many different kinds, the number being reducible if at all by scientific investigation and not by philosophy: pens are in many ways though not in all ways unlike rainbows, which are in many ways though not in all ways unlike after-images, which in turn are in many ways but not in all ways unlike pictures on the cinema-screen--and so on.
J. L. Austin"What is truth?" said jesting Pilate, and would not stay for an answer. Pilate was in advance of his time. For "truth" itself is an abstract noun, a camel, that is, of a logical construction, which cannot get past the eye even of a grammarian. We approach it cap and categories in hand: we ask ourselves whether Truth is a substance (the Truth, the Body of Knowledge), or a quality (something like the colour red, inhering in truths), or a relation ("correspondence"). But philosophers should take something more nearly their own size to strain at. What needs discussing rather is the use, or certain uses, of the word "true." In vino, possibly, "veritas," but in a sober symposium "verum."
J. L. Austin