Desire

Desires are states of mind that are expressed by terms like "wanting", "wishing", "longing" or "craving". A great variety of features is commonly associated with desires. They are seen as propositional attitudes towards conceivable states of affairs. They aim to change the world by representing how the world should be, unlike beliefs, which aim to represent how the world actually is. Desires are closely related to agency: they motivate the agent to realize them. For this to be possible, a desire has to be combined with a belief about which action would realize it. Desires present their objects in a favorable light, as something that appears to be good. Their fulfillment is normally experienced as pleasurable in contrast to the negative experience of failing to do so. Conscious desires are usually accompanied by some form of emotional response. While many researchers roughly agree on these general features, there is significant disagreement about how to define desires, i.e. which of these features are essential and which ones are merely accidental. Action-based theories define desires as structures that incline us toward actions. Pleasure-based theories focus on the tendency of desires to cause pleasure when fulfilled. Value-based theories identify desires with attitudes toward values, like judging or having an appearance that something is good.
Desires can be grouped into various types according to a few basic distinctions. Intrinsic desires concern what the subject wants for its own sake while instrumental desires are about what the subject wants for the sake of something else. Occurrent desires are either conscious or otherwise causally active, in contrast to standing desires, which exist somewhere in the back of one's mind. Propositional desires are directed at possible states of affairs while object-desires are directly about objects. Various authors distinguish between higher desires associated with spiritual or religious goals and lower desires, which are concerned with bodily or sensory pleasures. Desires play a role in many different fields. There is disagreement whether desires should be understood as practical reasons or whether we can have practical reasons without having a desire to follow them. According to fitting-attitude theories of value, an object is valuable if it is fitting to desire this object or if we ought to desire it. Desire-satisfaction theories of well-being state that a person's well-being is determined by whether that person's desires are satisfied.
Marketing and advertising companies have used psychological research on how desire is stimulated to find more effective ways to induce consumers into buying a given product or service. Techniques include creating a sense of lack in the viewer or associating the product with desirable attributes. Desire plays a key role in art. The theme of desire is at the core of romance novels, which often create drama by showing cases where human desire is impeded by social conventions, class, or cultural barriers. Melodrama films use plots that appeal to the heightened emotions of the audience by showing "crises of human emotion, failed romance or friendship", in which desire is thwarted or unrequited.

Theories

Theories of desire aim to define desires in terms of their essential features. A great variety of features are ascribed to desires, like that they are propositional attitudes, that they lead to actions, that their fulfillment tends to bring pleasure, etc. Across the different theories of desires, there is a broad agreement about what these features are. Their disagreement concerns which of these features belong to the essence of desires and which ones are merely accidental or contingent. Traditionally, the two most important theories define desires in terms of dispositions to cause actions or concerning their tendency to bring pleasure upon being fulfilled. An important alternative of more recent origin holds that desiring something means seeing the object of desire as valuable.

General features

A great variety of features is ascribed to desires. They are usually seen as attitudes toward conceivable states of affairs, often referred to as propositional attitudes. They differ from beliefs, which are also commonly seen as propositional attitudes, by their direction of fit. Both beliefs and desires are representations of the world. But while beliefs aim at truth, i.e. to represent how the world actually is, desires aim to change the world by representing how the world should be. These two modes of representation have been termed mind-to-world and world-to-mind direction of fit respectively. Desires can be either positive, in the sense that the subject wants a desirable state to be the case, or negative, in the sense that the subject wants an undesirable state not to be the case. It is usually held that desires come in varying strengths: some things are desired more strongly than other things. We desire things in regard to some features they have but usually not in regard to all of their features.
Desires are also closely related to agency: we normally try to realize our desires when acting. It is usually held that desires by themselves are not sufficient for actions: they have to be combined with beliefs. The desire to own a new mobile phone, for example, can only result in the action of ordering one online if paired with the belief that ordering it would contribute to the desire being fulfilled. The fulfillment of desires is normally experienced as pleasurable in contrast to the negative experience of failing to do so. But independently of whether the desire is fulfilled or not, there is a sense in which the desire presents its object in a favorable light, as something that appears to be good. Besides causing actions and pleasures, desires also have various effects on the mental life. One of these effects is to frequently move the subject's attention to the object of desire, specifically to its positive features. Another effect of special interest to psychology is the tendency of desires to promote reward-based learning, for example, in the form of operant conditioning.

Action-based theories

Action-based or motivational theories have traditionally been dominant. They can take different forms but they all have in common that they define desires as structures that incline us toward actions. This is especially relevant when ascribing desires, not from a first-person perspective, but from a third-person perspective. Action-based theories usually include some reference to beliefs in their definition, for example, that "to desire that P is to be disposed to bring it about that P, assuming one's beliefs are true". Despite their popularity and their usefulness for empirical investigations, action-based theories face various criticisms. These criticisms can roughly be divided into two groups. On the one hand, there are inclinations to act that are not based on desires. Evaluative beliefs about what we should do, for example, incline us toward doing it, even if we do not want to do it. There are also mental disorders that have a similar effect, like the tics associated with Tourette syndrome. On the other hand, there are desires that do not incline us toward action. These include desires for things we cannot change, for example, a mathematician's desire that the number Pi be a rational number. In some extreme cases, such desires may be very common, for example, a totally paralyzed person may have all kinds of regular desires but lacks any disposition to act due to the paralysis.

Pleasure-based theories

It is one important feature of desires that their fulfillment is pleasurable. Pleasure-based or hedonic theories use this feature as part of their definition of desires. According to one version, "to desire p is... to be disposed to take pleasure in it seeming that p and displeasure in it seeming that not-p". Hedonic theories avoid many of the problems faced by action-based theories: they allow that other things besides desires incline us to actions and they have no problems explaining how a paralyzed person can still have desires. But they also come with new problems of their own. One is that it is usually assumed that there is a causal relation between desires and pleasure: the satisfaction of desires is seen as the cause of the resulting pleasure. But this is only possible if cause and effect are two distinct things, not if they are identical. Apart from this, there may also be bad or misleading desires whose fulfillment does not bring the pleasure they originally seemed to promise.

Value-based theories

Value-based theories are of more recent origin than action-based theories and hedonic theories. They identify desires with attitudes toward values. Cognitivist versions, sometimes referred to as desire-as-belief theses, equate desires with beliefs that something is good, thereby categorizing desires as one type of belief. But such versions face the difficulty of explaining how we can have beliefs about what we should do despite not wanting to do it. A more promising approach identifies desires not with value-beliefs but with value-seemings. On this view, to desire to have one more drink is the same as it seeming good to the subject to have one more drink. But such a seeming is compatible with the subject having the opposite belief that having one more drink would be a bad idea. A closely related theory is due to T. M. Scanlon, who holds that desires are judgments of what we have reasons to do. Critics have pointed out that value-based theories have difficulties explaining how animals, like cats or dogs, can have desires, since they arguably cannot represent things as being good in the relevant sense.

Others

A great variety of other theories of desires have been proposed. Attention-based theories take the tendency of attention to keep returning to the desired object as the defining feature of desires. Learning-based theories define desires in terms of their tendency to promote reward-based learning, for example, in the form of operant conditioning. Functionalist theories define desires in terms of the causal roles played by internal states while interpretationist theories ascribe desires to persons or animals based on what would best explain their behavior. Holistic theories combine various of the aforementioned features in their definition of desires.