 Strawson made a major contribution to the theory of perception. His conception is articulated to some extent in The Bounds of Sense, but also in a series of articles, of which the most famous is ‘Perception and Its Objects’ (1979). He suggests that the concept of perception should be analysed as a causal concept. His version of the causal theory differs in two main respects from that of Grice, who also famously defended a similar analysis. First, Strawson’s argument for view turns on the idea that perception is essentially a method of acquiring knowledge; he suggests that this requires that the concept of perception is a causal concept. Second, Strawson claims that Grice’s attempt to spell out the right causal chain by picking it out via examples is circular, and he instead invokes notions of match and range. Strawson’s version attracted considerable attention. More important is Strawson’s claim that there is no way to describe perceptual experience in terms which are not physical-object concept involving. That this can be done, he thinks, is the crucial mistake of the traditional empiricist model, as represented, for example, in the thought of A. J. Ayer. According to Strawson we are not reading in or interpreting our experiences when we respond to them by making objective judgements; we are simply endorsing their content. Strawson therefore holds that it is myth to suppose that we can locate a level of claim on the basis of which we can defend the validity of our application of physical object concepts. Rather, our experience is ‘saturated’ by those concepts themselves. In a more recent terminology, Strawson holds that perception involves the occurrence in us of experiences having objective representational content, and that there can be hallucinations with a similar content but which are not properly perceptual because the complex causal requirements for being perceptual are not met. Strawson’s claims about perception are discussed in Snowdon 1998.