A rational agent adopts (or changes) its goals when new information (beliefs) becomes available or its desires (e.g., tasks it is supposed to carry out) change. In this paper we propose a non-conventional approach for adopting goals which takes the degree of trust in the sources of information into account. Beliefs, desires, and goals, as a consequence, are gradual. Incoming information may be any propositional formula.

Two algorithms for updating the mental state of an agent in this new setting are proposed. The first algorithm is relevant to the updating when a new piece of information arrives and the second one is relevant to the updating when a new desire arises.