Of his earlier work, he is perhaps best known for the first chapter of his 1983 book,
Sense and Content, entitled "Sensation and the Content of Experience." In this chapter, Peacocke defends the claim that perceptual experience, over and above its intentional content, has certain "sensational properties". He gives three different examples of visual scenarios where intentional content alone cannot capture every aspect of the experience. Those aspects which elude intentional content are thought to be the sensational properties of the experience. Some of those who defend
qualia have used these examples as evidence of their existence. Several philosophers have criticized these examples (
Michael Tye,
Fred Dretske), claiming that the supposed extra quality can indeed be captured in terms of intentional content. In
Sense and Content, Peacocke assumed that the intentional content of mental states is exclusively conceptual content, i.e. the content is such that the subject of the state needs to possess all the concepts that specify the intentional content in question. From about 1986 and onwards, Peacocke abandoned this assumption, arguing that some mental states, in particular perceptual experiences and representational states implicated in subpersonal information processing (for example, in the subconscious parsing of heard speech), have non-conceptual intentional content. Peacocke is now often seen as a leading proponent of this notion of non-conceptual intentional content. In his 1992 book
A Study of Concepts, Peacocke gives a detailed exposition of a philosophical theory of concept possession, according to which the nature and identity conditions for concepts may be given, in a non-circular way, by the conditions a thinker has to satisfy in order to possess the relevant concepts. The theory is a version of a so-called "conceptual" or "inferential role" theory of concepts. == Works ==