Folk psychology (sometimes called naïve psychology or common sense psychology) is the psychological theory implicit in our everyday ascriptions of others' actions, and includes concepts such as belief ("he thinks that Peter is wise"), desire ("she wants that piece of cake"), fear ("Alex is afraid of spiders") and hope ("she hopes that he is on time today"). Such ascriptions are collectively known as propositional attitudes.

It is often assumed people have developed this very useful and strikingly successful tool for predicting the behavior of other humans and animals. However, it is increasingly applied to technological devices and can be seen, for example, when someone exclaims that a computer is 'trying' to do something, or is 'thinking' about a calculation or process.

Folk theories, i.e. theories that are based on common, everyday experiences, but not subjected to rigorous experimental techniques, underlie many of our actions. For instance, a fairly sophisticated folk physics (the theory of the behavior of middle-sized, common objects, such as tables, chairs and bowling balls) is essential to our everyday interactions with the surrounding environment. Just think of all the assumptions you make about the clothing you are currently wearing, for example, that it is not going to melt, that it stays at a certain temperature range in standard conditions, that it will not protect you from missiles and so on. Similarly, folk psychology is considered the basis for many of our social actions and judgements about the psychology of others. It encompasses all of the assumptions we make about the correlations between people's behavior, mental states, and surrounding conditions.

Folk physics has been, to a large extent, discredited and shown to be thoroughly inadequate in providing robust explanations of various physical phenomena. This, of course, raises the question of how folk psychology would fare in this respect and this matter is a subject of lively debate in the philosophy of mind.

Philosophers take various attitudes toward the possibility of vindicating / extending folk psychology by allowing its theoretical terms (e.g. 'belief' 'desire' etc.) to play a role in serious scientific theorizing.

Among the advocates of such a possibility, Jerry Fodor is surely the most famous (for a defense of this view see his 1987 book "Psychosemantics"). The other extreme is exemplified by eliminative materialists, such as Paul and Patricia Churchland and Stephen Stich . Stich's book, "From Folk Psychology to Cognitive Science: The Case Against Belief" has received much attention in this regard.

Daniel Dennett's instrumentalist theory is, for some, a middle ground, as he concedes some aspects of eliminativism (arguing that folk psychology concepts can not be reduced to biology) whilst still seeing the value of folk psychological concepts as successful everday strategies.

See also

• belief
• eliminativism
• instrumentalism
• propositional attitude