Review of 'Consciousness and its Function' by David Rosenthal

David Rosenthal is a well-known defender of a particular kind of theory of consciousness known as the higher-order thought theory (HOTT). Higher-order theories are united by what Rosenthal calls the Transitivity Principle (TP), which states that a mental state is conscious iff one is conscious of oneself, in some suitable way, as being in that mental state. Since there are various ways to implement TP and HOTT commits one to the view that any mental state could occur unconsciously it seems to predict that a mental state’s being conscious doesn’t have any significant function to perform. An unconscious mental state, according to the theory, has most of its causal connections already, as evidenced by priming studies, subliminal perception, and other empirical findings. Given this, one early objection to HOTT was to emphasize this consequence of the theory. Since consciousness does have a function any theory which predicts that it doesn’t must be suspect. Rosenthal’s primary goal in this paper is to defend HOTT against this objection. In fact he argues that if we could establish that consciousness has no function independently of HOTT we would then have an analogous argument for it: Since consciousness doesn’t have any significant function any theory which predicts that it doesn’t fares be.