Partial Belief, Partial Intention

Abstract

Is a belief that one will succeed necessary for an intention? It is argued that the question has traditionally been badly posed, framed as it is in terms of all-out belief. We need instead to ask about the relation between intention and partial belief. An account of partial belief that is more psychologically realistic than the standard credence account is developed. A notion of partial intention is then developed, standing to all-out intention much as partial belief stands to all-out belief. Various coherence constraints on the notion are explored. It is concluded that the primary relations between intention and belief should be understood as normative and not essential. 8 For this criticism see Harman 1988, pp. 25-7. Put as I have put it, the complaint is overstated. Rather that assigning prior conditional probabilities to all pairs of propositions we might use Bayesian Networks, representations that implicitly assume that many factors are independent, and so drastically reduce the number of priors needed. For an introduction to Bayesian Networks, with clear discussion of this point, see Charniak, 1991. Nevertheless, the computational complexity remains outside our conscious ability. 9 The classic study here is Kahneman & Tversky, 1973; there has been much more since. See the articles collected in Kahneman & Tversky, 2000. 10 For review see Chater et al., 2006, and the articles that follow it in the same journal. 11 The comparison is from Chater et al 2006, p. 288.

Lying by Promising

“…W-COG*: S can rationally intend to Φ only if S has at least a partial belief that S will successfully Φ A similar view is defended by Holton (2008Holton ( :51-55, 2009, who claims that you rationally intend to Φ only if you take as a live possibility that you will Φ successfully. To put our example in his words, it is rational for me to intend to arrive to work on time as long as I take it as a live possibility that I will arrive to work on time.…”

“…Cognitivism is undeniable only as long as we move within a full-fledged belief framework (Holton 2008(Holton , 2009). Once credences (degrees of belief) are considered, rather than a binary opposition between believing and not believing it is possible to appreciate a number of intermediate cases: you may be certain that you will do what you intend to do, be uncertain that you will do it, believe it probable that you will do it, etc.…”

Cognitivism about Practical Rationality

“…So, it seems odd to say that one intends and one doesn't. 22 Holton (2008) makes the related point that an appeal to partial, as opposed to all-out, belief would allow for a response to Velleman's coordination argument for the Strong Belief Thesis. (Audi's view is that intention involves an all-out belief that success is more likely than not, not a partial belief in success.)…”

Trying to Act

“…And sometimes, also, when we recognize a diffi culty about doing something, we may devise a plan incorporating alternative means, so that we can be ready to try each of the alternatives (for more on this, see Holton 2008 ). The fact that we can fi nd ourselves with reasons precisely to try to do something represents an extension of the powers we have as agents.…”