Abstract

Reid declared Hume's appeal to variation in the magnitude of a table with distance to be the best argument that had ever been offered for the ‘ideal hypothesis’ that we experience nothing but our own mental states. Reid's principal objection to this argument fails to apply to minimally visible points. He did establish that we have reason to take our perceptions to be caused by external objects. But his case that we directly perceive external objects is undermined by what Hume had to say about the role played by color in our perception of the primary qualities of bodies.