Mental state
A mental state, or a mental property, is a state of mind of a person. Mental states comprise a diverse class, including perception, pain/pleasure experience, belief, desire, intention, emotion, and memory.
There is controversy concerning the exact definition of the term. According to epistemic approaches, the essential mark of mental states is that their subject has privileged epistemic access while others can only infer their existence from outward signs. Consciousness-based approaches hold that all mental states are either conscious themselves or stand in the right relation to conscious states. Intentionality-based approaches, on the other hand, see the power of minds to refer to objects and represent the world as the mark of the mental. According to functionalist approaches, mental states are defined in terms of their role in the causal network independent of their intrinsic properties. Some philosophers deny all the aforementioned approaches by holding that the term "mental" refers to a cluster of loosely related ideas without an underlying unifying feature shared by all.
Various overlapping classifications of mental states have been proposed. Important distinctions group mental phenomena together according to whether they are sensory, propositional, intentional, conscious or occurrent. Sensory states involve sense impressions like visual perceptions or bodily pains. Propositional attitudes, like beliefs and desires, are relations a subject has to a proposition. The characteristic of intentional states is that they refer to or are about objects or states of affairs. Conscious states are part of the phenomenal experience while occurrent states are causally efficacious within the owner's mind, with or without consciousness. An influential classification of mental states was created by Franz Brentano, who argues that there are only three basic kinds: presentations, judgments, and phenomena of love and hate.
Mental states are usually contrasted with physical or material aspects. For physicalists, they are a kind of high-level property that can be understood in terms of fine-grained neural activity. Property dualists, on the other hand, claim that no such reductive explanation is possible. Eliminativists may reject the existence of mental properties, or at least of those corresponding to folk psychological categories such as thought and memory. Mental states play an important role in various fields, including philosophy of mind, epistemology and cognitive science. In psychology, the term is used not just to refer to the individual mental states listed above but also to a more global assessment of a person's mental health.
Definition
Various competing theories have been proposed about what the essential features of all mental states are, sometimes referred to as the search for the "mark of the mental". These theories can roughly be divided into epistemic approaches, consciousness-based approaches, intentionality-based approaches and functionalism. These approaches disagree not just on how mentality is to be defined but also on which states count as mental. Mental states encompass a diverse group of aspects of an entity, like this entity's beliefs, desires, intentions, or pain experiences. The different approaches often result in a satisfactory characterization of only some of them. This has prompted some philosophers to doubt that there is a unifying mark of the mental and instead see the term "mental" as referring to a cluster of loosely related ideas. Mental states are usually contrasted with physical or material aspects. This contrast is commonly based on the idea that certain features of mental phenomena are not present in the material universe as described by the natural sciences and may even be incompatible with it.Epistemic and consciousness-based approaches
Epistemic approaches emphasize that the subject has privileged access to all or at least some of their mental states. It is sometimes claimed that this access is direct, private and infallible. Direct access refers to non-inferential knowledge. When someone is in pain, for example, they know directly that they are in pain, they do not need to infer it from other indicators like a body part being swollen or their tendency to scream when it is touched. But we arguably also have non-inferential knowledge of external objects, like trees or cats, through perception, which is why this criterion by itself is not sufficient. Another epistemic privilege often mentioned is that mental states are private in contrast to public external facts. For example, the fallen tree lying on a person's leg is directly open to perception by the bystanders while the victim's pain is private: only they know it directly while the bystanders have to infer it from their screams. It was traditionally often claimed that we have infallible knowledge of our own mental states, i.e. that we cannot be wrong about them when we have them. So when someone has an itching sensation, for example, they cannot be wrong about having this sensation. They can only be wrong about the non-mental causes, e.g. whether it is the consequence of bug bites or of a fungal infection. But various counterexamples have been presented to claims of infallibility, which is why this criterion is usually not accepted in contemporary philosophy. One problem for all epistemic approaches to the mark of the mental is that they focus mainly on conscious states but exclude unconscious states. A repressed desire, for example, is a mental state to which the subject lacks the forms of privileged epistemic access mentioned.One way to respond to this worry is to ascribe a privileged status to conscious mental states. On such a consciousness-based approach, conscious mental states are non-derivative constituents of the mind while unconscious states somehow depend on their conscious counterparts for their existence. An influential example of this position is due to John Searle, who holds that unconscious mental states have to be accessible to consciousness to count as "mental" at all. They can be understood as dispositions to bring about conscious states. This position denies that the so-called "deep unconscious", i.e. mental contents inaccessible to consciousness, exists. Another problem for consciousness-based approaches, besides the issue of accounting for the unconscious mind, is to elucidate the nature of consciousness itself. Consciousness-based approaches are usually interested in phenomenal consciousness, i.e. in qualitative experience, rather than access consciousness, which refers to information being available for reasoning and guiding behavior. Conscious mental states are normally characterized as qualitative and subjective, i.e. that there is something it is like for a subject to be in these states. Opponents of consciousness-based approaches often point out that despite these attempts, it is still very unclear what the term "phenomenal consciousness" is supposed to mean. This is important because not much would be gained theoretically by defining one ill-understood term in terms of another. Another objection to this type of approach is to deny that the conscious mind has a privileged status in relation to the unconscious mind, for example, by insisting that the deep unconscious exists.
Intentionality-based approaches
Intentionality-based approaches see intentionality as the mark of the mental. The originator of this approach is Franz Brentano, who defined intentionality as the characteristic of mental states to refer to or be about objects. One central idea for this approach is that minds represent the world around them, which is not the case for regular physical objects. So a person who believes that there is ice cream in the fridge represents the world as being a certain way. The ice cream can be represented but it does not itself represent the world. This is why a mind is ascribed to the person but not to the ice cream, according to the intentional approach. One advantage of it in comparison to the epistemic approach is that it has no problems to account for unconscious mental states: they can be intentional just like conscious mental states and thereby qualify as constituents of the mind. But a problem for this approach is that there are also some non-mental entities that have intentionality, like maps or linguistic expressions. One response to this problem is to hold that the intentionality of non-mental entities is somehow derivative in relation to the intentionality of mental entities. For example, a map of Addis Ababa may be said to represent Addis Ababa not intrinsically but only extrinsically because people interpret it as a representation. Another difficulty is that not all mental states seem to be intentional. So while beliefs and desires are forms of representation, this seems not to be the case for pains and itches, which may indicate a problem without representing it. But some theorists have argued that even these apparent counterexamples should be considered intentional when properly understood.Behaviorism and functionalism
Behaviorist definitions characterize mental states as dispositions to engage in certain publicly observable behavior as a reaction to particular external stimuli. On this view, to ascribe a belief to someone is to describe the tendency of this person to behave in certain ways. Such an ascription does not involve any claims about the internal states of this person, it only talks about behavioral tendencies. A strong motivation for such a position comes from empiricist considerations stressing the importance of observation and the lack thereof in the case of private internal mental states. This is sometimes combined with the thesis that we could not even learn how to use mental terms without reference to the behavior associated with them. One problem for behaviorism is that the same entity often behaves differently despite being in the same situation as before. This suggests that explanation needs to make reference to the internal states of the entity that mediate the link between stimulus and response. This problem is avoided by functionalist approaches, which define mental states through their causal roles but allow both external and internal events in their causal network. On this view, the definition of pain-state may include aspects such as being in a state that "tends to be caused by bodily injury, to produce the belief that something is wrong with the body and... to cause wincing or moaning".One important aspect of both behaviorist and functionalist approaches is that, according to them, the mind is multiply realizable. This means that it does not depend on the exact constitution of an entity for whether it has a mind or not. Instead, only its behavioral dispositions or its role in the causal network matter. The entity in question may be a human, an animal, a silicon-based alien or a robot. Functionalists sometimes draw an analogy to the software-hardware distinction where the mind is likened to a certain type of software that can be installed on different forms of hardware. Closely linked to this analogy is the thesis of computationalism, which defines the mind as an information processing system that is physically implemented by the neural activity of the brain.
One problem for all of these views is that they seem to be unable to account for the phenomenal consciousness of the mind emphasized by consciousness-based approaches. It may be true that pains are caused by bodily injuries and themselves produce certain beliefs and moaning behavior. But the causal profile of pain remains silent on the intrinsic unpleasantness of the painful experience itself. Some states that are not painful to the subject at all may even fit these characterizations.