Conscious attention to an object, singling it out in experience, provides knowledge of the reference of a demonstrative term. Knowledge of reference is the foundation of the ability to verify propositions about the object and of the ability to act on the object. To understand the relations between knowledge of reference, verification, and action, we have to look at the relations between conscious attention, visual information processing, and the motor system.Why should it be specifically conscious attention that provides the knowledge of reference? Knowledge of reference demands acquaintance with the individual, categorical substances around us, and not merely collections of affordances. I argue that only experience of objects can provide this kind of acquaintance with individual substances.The approach is extended beyond understanding one's own uses of visual demonstratives to cases of joint attention and to memory demonstratives. The approach has implications for Dummett's anti‐realism and Quine's theses of inscrutability and indeterminacy. The book concludes with remarks on the metaphysics of individual substances.