Philosophy & cognitive science

Joe Lau
The University of Hong Kong
1st semester 2005-06
July 20 2024

Examples of mental states

Mental states are states of the mind, such as :


One meaning of "Intentionality" is aboutness or directedness. A mental state is an intentional mental state (has intentionality) when it is about about, or directed at some object. Beliefs are necessarily intentional mental states. It is impossible to have a belief without the belief being about something. If you believe that the earth is round, your belief is about the earth. If you are looking at a bird, your perceptual experience is directed at the bird. So these are examples of intentional mental states. Similarly, desire is also an intentional mental state - it is impossible to have a desire without the desire being a desire about something.

Notice that an intentional mental state can be about something that does not actually exist. A little girl might believe that Santa Claus lives in Finland. Her belief is about Santa Claus even though Santa Claus does not exist.

Are all mental states intentional mental states?

This is actually quite a controversial topic. Not all philosophers think that all mental states are intentional. Some philosophers think that mental states such as pain or itches are not about anything at all, and so they are non-intentional mental states. It certainly seems strange to speak of a pain as being "about" something.

On the other hand, it does not seem strange to say that pains and itches are states that carry information. We might say that a pain carries information about what is happening to our body, for example. In cases of phantom limbs, patients who have their limbs amputated might continue to feel pain which they locate in body parts that no longer exist. One way to understand this is to say that their pains are misrepresentations in that they carry false information about their bodies. This is somewhat similar to having false beliefs. So if we understand intentionality as carrying information then perhaps pains and itches can be seen as intentional too.

However, if this is the definition of intentionality, we might not be able to say that desires are intentional states. We do not normally say that desires carry information. If I desire sugar my desire is about sugar, but the desire does not carry any information about sugar. Perhaps we can define an intentional mental state as any mental state that either is about something or carries information. Then beliefs, desires and pains can all be regarded as intentional mental states.

This issue relates to the question of whether there is "a mark of the mental". This is just the question of whether there is any distinctive feature that is unique to all mental states, a feature that all and only mental states possess. Perhaps intentionality is the mark of the mental. On the other hand, perhaps the concept of the mental is vague and there is no precise definition of mentality.


Whatever we think about the intentionality of pains and itches, they are at least conscious mental states. Philosophers these days like to say that a conscious mental state is a mental state for which there is something it is like to be in it. If a creature is having a conscious mental state, there is something it is like to be that creature. Whereas there is nothing it is like to be a stone. There is, however, something it is like to be in pain, and what it is like to be in pain is what is distinctive about pain. There is also something it is like to have an itch, and it is different from what it is like to be in pain. Conscious mental states are also called phenomenal states.

Not all intentional states are conscious

However, a belief is not regarded as a conscious mental state, or at least it is not always a conscious mental state. You do not cease to believe that 1+1=2 when you are sleeping, but there is nothing it is like at that time to have the belief. If Freud is right, then perhaps even some emotions can be unconscious. Perhaps it is possible for unconscious anger toward a person to manifest itself in nasty behavior toward that person, but the one who is angry actually does not feel the anger.

Some mental states are both intentional and conscious

Mental imagery is one example. If you imagine yourself flying above the ocean presumably you have some kind of conscious experience. It is a bit like having a picture in one's mind. On the other hand this state of our imagination has content : it is about you flying above the ocean. Or consider a different example. Suppose you feel very angry at your boyfriend. This is again a conscious mental state since there is something it is like to feel anger. But your anger is also an intentional state since it is directed at your boyfriend. Your state of anger is a state about him.

Are all mental states intentional, conscious, or both?

Many mental states seem to be analyzable in terms of some combination of intentional and conscious states. It seems that the same is true for character or personality traits. An optimistic person is one who is disposed to have certain types of thoughts or feelings. We should bear this in mind when we ask whether computers can (or cannot) have some particular mental state X. This becomes the question of whether computers can have mental states A, B, and C, if X is composed of mental states A, B, and C.

Some other points to bear in mind

There might be different types of minds. Having mental states sufficies for having a mind, but there is no reason that all minds must have the same sort of mental states. Perhaps animal minds are different from human minds, and they are both different from the minds of robots or ghosts or whatever. So we should not argue from (a) "X cannot have mental state Y" to (b) "X cannot have a mind".

It is not clear whether having a mind requires having both intentional mental states and having conscious mental states. Is it possible for a system to have only intentional mental states but no conscious experience?

Derived intentionality

Sometimes a distinction is made between original and derived intentionality. Sentences, pictures and diagrams are also intentional objects since there are things they might be about. But their intentionality derives from our minds and so they have derived intentionality, whereas our mental states have original intentionality.