Date of Award

Spring 1-1-2011

Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Robert Rupert

Second Advisor

Brad Monton

Third Advisor

Carol Cleland


This dissertation defends the explanatory value of unconscious mental states. Unconscious mental states are a subject’s information-bearing states with certain properties. These states possess features that make them mental states but do not possess the properties that make them conscious mental states. The claim is that some human behaviors, driven by perceptual and cognitive mental states, are best explained by employing unconscious mental states of one kind or another. The general idea is that the explanatory value of unconscious mental states equals the number of a subject’s behaviors valuably explained by their mental states minus the number of the subject’s behaviors that are valuably explained by their conscious mental states.

Support for the claim that some human behaviors are best explained by employing unconscious mental states comes in three forms. First, there is a coherent information-processing model for mental states. This model can account for certain of a subject’s perceptually and cognitively driven behaviors, in part or whole, with unconscious mental states. Second, independent criteria regarding human subject’s conscious mental states support explanations that use unconscious mental states. Finally, unconscious mental states are supported by the success of models that employ such states found in modern psychological and neurological explanations of some human behaviors. This dissertation will also support the idea that the set of unconscious mental states in human subjects are moderately unified, made of various kinds, and are numerous.

Unconscious mental states in empirical psychology and neuroscience are often called a subject’s “cognitive unconscious” (Kihlstrom 1987). The explanatory value of the “cognitive unconscious” has been recently attacked, for example by Searle (1990), as well as others. This dissertation defends the explanatory value of the cognitive unconscious against these attacks.