According to Ayer, meaningful factual statements can be reduced to claims about sense data. While he seemed at times to temper this view, over his career he stuck to sense data as the foundation of empirical knowledge. In a famous exchange with the ordinary language philosopher J.L. Austin (1911–1960), Ayer defended his theory of sense data. Ayer’s position was that sense data are not directly intuited until they have led to a perception of the ordinary world, with all of its normally perceptible objects, such as tables and chairs. Austin, who was a colleague of Ayer’s at Cambridge, held that Ayer’s theory of sense data could not be a form of foundationism because it presupposed common sense reality. That is, Austin’s claim against Ayer was that, contrary to how Ayer seemed to present his case, perceptual knowledge was not built up of sense data. Ayer defended his view by claiming that in the process of verification sense data were necessary to confirm perceptions.