Belief
A belief is a subjective attitude that something is true or a state of affairs is the case. A subjective attitude is a mental state of having some stance, take, or opinion about something. In epistemology, philosophers use the term belief to refer to attitudes about the world which can be either true or false. To believe something is to take it to be true; for instance, to believe that snow is white is comparable to accepting the truth of the proposition "snow is white". However, holding a belief does not require active introspection. For example, few individuals carefully consider whether or not the sun will rise the next morning, simply assuming that it will. Moreover, beliefs need not be occurrent, but can instead be dispositional.
There are various ways that contemporary philosophers have tried to describe beliefs, including as representations of ways that the world could be, as dispositions to act as if certain things are true, as interpretive schemes for making sense of someone's actions, or as mental states that fill a particular function. Some have also attempted to offer significant revisions to our notion of belief, including eliminativists about belief who argue that there is no phenomenon in the natural world which corresponds to our folk psychological concept of belief and formal epistemologists who aim to replace our bivalent notion of belief with the more permissive, probabilistic notion of credence.
Beliefs are the subject of various important philosophical debates. Notable examples include: "What is the rational way to revise one's beliefs when presented with various sorts of evidence?", "Is the content of our beliefs entirely determined by our mental states, or do the relevant facts have any bearing on our beliefs ?", "How fine-grained or coarse-grained are our beliefs?", and "Must it be possible for a belief to be expressible in language, or are there non-linguistic beliefs?"
Conceptions
Various conceptions of the essential features of beliefs have been proposed, but there is no consensus as to which is the right one. Representationalism is the traditionally dominant position. Its most popular version maintains that attitudes toward representations, which are typically associated with propositions, are mental attitudes that constitute beliefs. These attitudes are part of the internal constitution of the mind holding the attitude. This view contrasts with functionalism, which defines beliefs not in terms of the internal constitution of the mind but in terms of the function or the causal role played by beliefs. According to dispositionalism, beliefs are identified with dispositions to behave in certain ways. This view can be seen as a form of functionalism, defining beliefs in terms of the behavior they tend to cause. Interpretationism constitutes another conception, which has gained popularity in contemporary philosophy. It holds that the beliefs of an entity are in some sense dependent on or relative to someone's interpretation of this entity. Representationalism tends to be associated with mind-body-dualism. Naturalist considerations against this dualism are among the motivations for choosing one of the alternative conceptions.Representationalism
Representationalism characterizes beliefs in terms of mental representations. Representations are usually defined as objects with semantic propertieslike having content, referring to something, or being true or false. Beliefs form a special class of mental representations since they do not involve sensory qualities in order to represent something, unlike perceptions or episodic memories. Because of this, it seems natural to construe beliefs as attitudes towards propositions, which also constitute non-sensory representations, i.e. as propositional attitudes. As mental attitudes, beliefs are characterized by both their content and their mode. The content of an attitude is what this attitude is directed at: its object. Propositional attitudes are directed at propositions. Beliefs are usually distinguished from other propositional attitudes, like desires, by their mode or the way in which they are directed at propositions. The mode of beliefs has a mind-to-world direction of fit: beliefs try to represent the world as it is; they do not, unlike desires, involve an intention to change it. For example, if Rahul believes that it will be sunny today, then he has a mental attitude towards the proposition "It will be sunny today" which affirms that this proposition is true. This is different from Sofía's desire that it will be sunny today, despite the fact that both Rahul and Sofía have attitudes toward the same proposition. The mind-to-world direction of fit of beliefs is sometimes expressed by saying that beliefs aim at truth. This aim is also reflected in the tendency to revise one's belief upon receiving new evidence that an existing belief is false. Upon hearing a forecast of bad weather, Rahul is likely to change his mental attitude but Sofía is not.There are different ways of conceiving how mental representations are realized in the mind. One form of this is the language of thought hypothesis, which claims that mental representations have a language-like structure, sometimes referred to as "mentalese". Just like regular language, this involves simple elements that are combined in various ways according to syntactic rules to form more complex elements that act as bearers of meaning. On this conception, holding a belief would involve storing such a complex element in one's mind. Different beliefs are separated from each other in that they correspond to different elements stored in the mind. A more holistic alternative to the "language of thought hypothesis" is the map-conception, which uses an analogy of maps to elucidate the nature of beliefs. According to this view, the belief system of a mind should be conceived of not as a set of many individual sentences but as a map encoding the information contained in these sentences. For example, the fact that Brussels is halfway between Paris and Amsterdam can be expressed both linguistically as a sentence and in a map through its internal geometrical relations.
Functionalism
contrasts with representationalism in that it defines beliefs not in terms of the internal constitution of the mind but in terms of the function or the causal role played by them. This view is often combined with the idea that the same belief can be realized in various ways and that it does not matter how it is realized as long as it plays the causal role characteristic to it. As an analogy, a hard drive is defined in a functionalist manner: it performs the function of storing and retrieving digital data. This function can be realized in many different ways: being made of plastic or steel, or using magnetism or laser. Functionalists hold that something similar is true for beliefs. Among the roles relevant to beliefs is their relation to perceptions and to actions: perceptions usually cause beliefs and beliefs cause actions. For example, seeing that a traffic light has switched to red is usually associated with a belief that the light is red, which in turn causes the driver to bring the car to a halt. Functionalists use such characteristics to define beliefs: whatever is caused by perceptions in a certain way and also causes behavior in a certain way is called a belief. This is not just true for humans but may include animals, hypothetical aliens or even computers. From this perspective, it would make sense to ascribe the belief that a traffic light is red to a self-driving car behaving just like a human driver.Dispositionalism is sometimes seen as a specific form of functionalism. It defines beliefs only concerning their role as causes of behavior or as dispositions to behave in a certain way. For example, a belief that there is a pie in the pantry is associated with the disposition to affirm this when asked and to go to the pantry when hungry. While it is uncontroversial that beliefs shape our behavior, the thesis that beliefs can be defined exclusively through their role in producing behavior has been contested. The problem arises because the mechanisms shaping our behavior seem to be too complex to single out the general contribution of one particular belief for any possible situation. For example, one may decide not to affirm that there is a pie in the pantry when asked because one wants to keep it secret. Or one might not eat the pie despite being hungry, because one also believes that it is poisoned. Due to this complexity, we are unable to define even a belief as simple as this one in terms of the behavioral dispositions for which it could be responsible.
Interpretationism
According to interpretationism, the beliefs of an entity are in some sense dependent on, or relative to, someone's interpretation of this entity. Daniel Dennett is an important defender of such a position. He holds that we ascribe beliefs to entities in order to predict how they will behave. Entities with simple behavioral patterns can be described using physical laws or in terms of their function. Dennett refers to these forms of explanation as the "physical stance" and the "design stance". These stances are contrasted with the intentional stance, which is applied to entities with a more complex behavior by ascribing beliefs and desires to these entities. For example, we can predict that a chess player will move her queen to f7 if we ascribe to her the desire to win the game and the belief that this move will achieve that. The same procedure can also be applied to predicting how a chess computer will behave. The entity has the belief in question if this belief can be used to predict its behavior. Having a belief is relative to an interpretation since there may be different equally good ways of ascribing beliefs to predict behavior. So there may be another interpretation that predicts the move of the queen to f7 that does not involve the belief that this move will win the game. Another version of interpretationism is due to Donald Davidson, who uses the thought experiment of radical interpretation, in which the goal is to make sense of the behavior and language of another person from scratch without any knowledge of this person's language. This process involves ascribing beliefs and desires to the speaker. The speaker really has these beliefs if this project can be successful in principle.Interpretationism can be combined with eliminativism and instrumentalism about beliefs. Eliminativists hold that, strictly speaking, there are no beliefs. Instrumentalists agree with eliminativists but add that belief-ascriptions are useful nonetheless. This usefulness can be explained in terms of interpretationism: belief-ascriptions help us in predicting how entities will behave. It has been argued that interpretationism can also be understood in a more realistic sense: that entities really have the beliefs ascribed to them and that these beliefs participate in the causal network. But, for this to be possible, it may be necessary to define interpretationism as a methodology and not as an ontological outlook on beliefs.