I argue in this essay that belief/desire explanations are not logically true and not causal, and further that the antecedent of a true belief/desire conditional cannot be strengthened in such a way as to transform it into a true causal statement. I also argue that belief/desire explanations are not dispensable: they are presupposed in our justifications of scientific claims. The proposal is not that psychological determinism is false, but that some at least of our activities are not describable in causal (...) terms. These arguments prepare the ground for a puzzle. If all human intentional behaviour is caused, then all actual linkages between psychological states and behaviour should be expressed in causal statements. But neither the action of asserting a causal statement nor the action of justifying the assertion can be described as the result of a cause. Therefore if one accepts that scientific claims can be justified, not all linkages between psychological states and subsequent action are expressible in causal statements. I do not offer a solution to this puzzle. (shrink)

A formal treatment of the logic of a type of conditional found in natural speech which differs substantially from the material conditional of propositional logic and from the conditionals afforded by theories of possible worlds.