  The first requirement may look trivial but it is not. For Hume, for example, what makes a group of experiences one person’s experiences is that they are associated with one another in an appropriate way (the so-called bundle theory), not that they have a common subject. The need for a subject arises from two straightforward considerations: representations not only represent something, they represent it to someone; and, representations are not given to us – to become a representation, sensory inputs must be processed by an integrated cognitive system. Kant may have been conscious of both these points, but beyond identifying the need, he had little to say about what the subject of experience might be like, so we will say no more about it. (We will, however, say something about what its consciousness of itself is like later.)