I don’t have a strong view on the original setup, but I can clarify what the argument is. For the first point, that we maximize E(CE)+S(CS). The idea is that we want to maximize the likelihood that the organism chooses the action that leads to enjoyment (the one being selected for). That probability is a function of how much better it is to choose that action than the alternative. So if you get E from choosing that action and lose S from choosing the alternative, the benefit from choosing that action is E - (-S) = E + S. However, you only pay to produce the experience of the action you actually take. This last reason is why the costs are weighted by probability, while the benefits, which are only about the anticipation of the experience you would get conditional on your action, are not.
It occurs to me that a fuller model might endogenize n, i.e. be something like max P(E(C_E) + S(C_S)) s.t. P(.) C_E + (1 - P(.)) C_S = M. (Replacing n with 1 - P here so it’s a rate, not a level. Also, perhaps this reduces to the same thing based on the envelope theorem.)
And on the last point, that point is relevant for the interpretation of the model (e.g. choosing the value of n), but it is not an assumption of the model.
I don’t have a strong view on the original setup, but I can clarify what the argument is. For the first point, that we maximize E(CE)+S(CS). The idea is that we want to maximize the likelihood that the organism chooses the action that leads to enjoyment (the one being selected for). That probability is a function of how much better it is to choose that action than the alternative. So if you get E from choosing that action and lose S from choosing the alternative, the benefit from choosing that action is E - (-S) = E + S. However, you only pay to produce the experience of the action you actually take. This last reason is why the costs are weighted by probability, while the benefits, which are only about the anticipation of the experience you would get conditional on your action, are not.
It occurs to me that a fuller model might endogenize n, i.e. be something like max P(E(C_E) + S(C_S)) s.t. P(.) C_E + (1 - P(.)) C_S = M. (Replacing n with 1 - P here so it’s a rate, not a level. Also, perhaps this reduces to the same thing based on the envelope theorem.)
And on the last point, that point is relevant for the interpretation of the model (e.g. choosing the value of n), but it is not an assumption of the model.