Higher-Order Thought and Borderline Cases of Consciousness: An Objection to HOT

David Rosenthal, in his Higher-Order Thought (HOT) theory of consciousness, argues that it is a higher-order thought to the effect that the subject is in a conscious state that makes one conscious of his or her own mental states. In this paper, I argue that since phenomenal consciousness can be vague and Rosenthal’s HOT cannot, HOT is not a necessary condition of phenomenal consciousness. I use primarily Ned Blocks’ refrigerator hum case and Sartre’s example of non-positional awareness to argue that the threshold which determines the degree of first-person awareness necessary for a mental state to be conscious is vague itself, therefore consciousness is a vague concept. HOT cannot accommodate for borderline cases of phenomenal consciousness, therefore it cannot be a necessary condition of all conscious mental states. This is especially relevant in the discussion of non-human animal consciousness, as HOT theories such as Carruthers have been used to deny non-human animal consciousness on the basis of the on/off feature of such representational theories