Academia[edit]
Discussions about mental states can be found in many areas of study.
In cognitive psychology and the philosophy of mind, a mental state is a kind of hypothetical state that corresponds to thinking and feeling, and consists of a conglomeration of mental representations and propositional attitudes. Several theories in philosophy and psychology try to determine the relationship between the agent's mental state and a proposition.[97][98][99][100]
Instead of looking into what a mental state is, in itself, clinical psychology and psychiatry determine a person's mental health through a mental status examination.[101]
Epistemology[edit]
Mental states also include attitudes towards propositions, of which there are at least two—factive and non-factive, both of which entail the mental state of acquaintance. To be acquainted with a proposition is to understand its meaning and be able to entertain it. The proposition can be true or false, and acquaintance requires no specific attitude towards that truth or falsity. Factive attitudes include those mental states that are attached to the truth of the proposition—i.e. the proposition entails truth. Some factive mental states include "perceiving that", "remembering that", "regretting that", and (more controversially) "knowing that".[102] Non-factive attitudes do not entail the truth of the propositions to which they are attached. That is, one can be in one of these mental states and the proposition can be false. An example of a non-factive attitude is believing—people can believe a false proposition and people can believe a true proposition. Since there is the possibility of both, such mental states do not entail truth, and therefore, are not factive. However, belief does entail an attitude of assent toward the presumed truth of the proposition (whether or not it is so), making it and other non-factive attitudes different from a mere acquaintance.