Possibility and Necessity in arguments from reason

A redated post. 

Steve Esser, who has in general been skeptical of the argument from reason, think that our ability to think in terms of necessity and possibility is something that is difficult to explain naturalistically. The idea might go like this: if our reasoning is based on an interaction with the environment, presumably the environment is actually in one state. How is it possible for us to think in terms of possibilities, if all we interact with is the actual world?