 Still, there are then two main dimensions along which higher-order theorists disagree amongst themselves. One concerns whether the higher-order states in question are perception-like, on the one hand, or thought-like, on the other. A thought is composed of or constituted by concepts. Those taking the former option are higher-order perception (often called ‘inner-sense’) theorists, and those taking the latter option are higher-order thought theorists. The two theories are therefore often abbreviated as HOP (higher-order perception) and HOT (higher-order thought) theory. The other general disagreement is internal to higher-order thought approaches, and concerns whether the relevant relation between the first-order state and the higher-order thought is one of availability or not. That is, the question is whether a state is conscious by virtue of being disposed to give rise to a higher-order thought, or rather by virtue of being the actual target of such a thought. These are the three main options that will now concern us. (A fourth will be considered in section 6.)