         Finally, according to David Rosenthal’s “higher-order thought” theory of consciousness, what makes a person’s mental state conscious is that the person is conscious of it by virtue of having formed a higher-order thought (or HOT) about it. Furthermore, the phenomenal character of a person’s sensory experience—what it is like for the person to be in that state—arises from the fact that the person has formed a HOT about it. The problem with the HOT theory of phenomenal consciousness is that the theory entails that creatures who, like non-human animals and human babies, lack the ability to form HOTs will be deprived of phenomenal consciousness—a consequence many will find implausible (cf. Rosenthal, 1986, 2005). For further discussion, see the SEP entries on  consciousness and intentionality  and   higher-order theories of consciousness.