The technical termdirection of fit is used to describe the distinctions that are offered by two related sets of opposing terms:
The more general set of mind-to-worldvs.world-to-mind used by philosophers of mind, and
The narrower, more specific set, word-to-worldvs.world-to-word used by advocates of speech act theory such as John Searle.
In general
In philosophy of mind, a belief has a mind-to-world direction of fit. A belief depicts the world as being in a state of affairs such that p is true. Beliefs, some philosophers have argued, aim at the truth and so aim to fit the world. A belief is satisfied when it fits the world. A desire, on the other hand, normally expresses a yet to be realized state of affairs and so has a world-to-mind direction of fit. A desire that p, unlike a belief, doesn't depict the world as being in the state that p; rather it expresses a desire that the world be such that p is true. Desire is a state that is satisfied when the world fits it. A way to account for the difference is that a person that holds the belief that p when confronted with evidence that not-p, will revise his belief, whereas a person that desires that p can retain his desire that p in the face of evidence that not-p. To a philosopher of language a word-to-world fit occurs when, say, a sports journalist correctly names Jones as a goal scorer; while if the journalist mistakenly names Smith as the goal scorer, the printed account does notdisplay a word-to-world fit, and must be altered such that it matches the real world. Conversely, a world-to-word fit occurs when a fan of Smith's team opines that they deserved to win the match, even though they lost. In this case, the world would have to change to make the sports fan's wish become true. However, in the case of, say, a judge delivering a death sentence to a criminal declared guilty by a jury, the utterances of the judge alter the world, through the fact of that utterance; and, in this case, the judge is generating a world-to-word-to-world fit. So, if the judge's opinion is upheld, the world must be altered to match the content of the judge's utterance.
Perhaps the first to speak of a "direction of fit" was the philosopher J. L. Austin. Austin did not use the distinction between different directions of fit to contrast commands or expressions of intention to assertions, or desires to beliefs. He rather distinguishes different ways of asserting that an item is of a certain type. In an extensive discussion of the issues involved with the differences between, say, wrongly calling a triangle a square and wrongly describing a triangular object as being a square, Austin distinguished between what he termed:
"the onus of match": in the case of one wanting to matchX and Y, the distinction between the matching of X to Y and the matching of Y to X; and
"the direction of fit": in the case of naming something, the difference between the fitting of a name to an item, and the fitting of an item to a name.
The concept of direction of fit can also apply to speech acts: e.g., statements, guesses and conjectures have word-to-world direction of fit, while commands and promises have a world-to-word direction of fit. John Searle and Daniel Vanderveken assert that there are only four possible "directions of fit" in language: Searle used this notion of "direction of fit" to create a taxonomy of illocutionary acts.
Although Elizabeth Anscombe never employed the term "the direction of fit", Searle has strongly argued that the following passage from her work Intention was, by far, "the best illustration" of the distinction between the tasks of " the words to match the world… the world to match the words":
In philosophy of mind
According to Velleman, when used in the domain of the philosophy of mind, the concept direction of fit represents the distinguishing feature between two types of intentional :wikt:mental state|mental states: In some forms of mind-body dualism, a matching factum and faciendum must be present in a person's mind in order for him to actintentionally. If a person has the belief that action will lead to state, and has the desire that state obtain, then he will perform action. The action is directly caused by simultaneous presence of the two mental states; no further explanation is needed. According to Velleman: