linguistic:voice_change, stylistic:tone, linguistic:paraphrasing, structural:scholar_edition
Functionalism

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 (or mental states in general). 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.