Let me start by briefly summing up my understanding of Stalnaker's position in chapter 5. Stalnaker holds that if we allow the concept of acceptance states which are more fundamental than belief or desire states, then we can explain conflicting beliefs as beliefs held in different acceptance states, and deductive reasoning as the understanding which accompanies the merger of two acceptance states. For the acceptance state hypothesis to be true means that the three conditions Stalnaker lays out on pg. 82 must always be true:
1. If P is a member of a set of accepted propositions, and P entails Q, then Q is a member of that set.
2 If P and Q are each members of a set of accepted propositions, then P & Q is a member of that set.
3. If P is a member of a set of accepted propositions, then not-P is not a member of that set.
I think one of the key claims Stalnaker makes is that acceptance can be compartmentalized. This is also the first thing I would like to question. What gives us the ability to compartmentalize our acceptance states? Is it the fact that we can suspend belief periodically to allow different sets of circumstances (different acceptance states)? For instance, in philosophy we sometimes use extraodinary hypothetical situations which could never actually happen in real life to test a hypothesis. Are we not temporarily suspending our beliefs about the world right now to entertain the beliefs of a different acceptance state? The fact that beliefs could affect acceptance states (and not the other way arround) seems to suggest that beliefs are more fundamental (I'm not sure how Kosher this is).
1. If A causes changes in B, then A is more fundamental than B.
2. Beliefs/desires cause the change in acceptance states.
3. Therefore, Beliefs/desires are more fundamental than acceptance states.
I think another problem with Stalnaker's view is that the problem of Deduction poses a bigger problem than he gives credit. I do not think that his answer of tacit beliefs and active beliefs solves the problem because both are still beliefs that you must actually hold. Hypothetically speaking, what if an acceptance state of mine entailed a belief which I could not hold because we are not sufficiently evolved enough at this point to grasp such a concept? Would that concept still count as a tacit belief?
1. I believe that P
2. P entails that afsoldifjsewoifse (my mind cannot grasp such a concept so I mashed keys)
3. I believe that afsoldifjsewoifse
I realize that the trick here is that I could never find an actual example of this to show Stalnaker because recognizing such an example would mean that I could grasp afsoldifjsewoifse to begin with. I guess you would have to add a premise 4 to the above argument where 4. There exists concepts that my mind cannot grasp which can be logically entailed by my current beliefs.
My last thought is that there seems to be something fishy about having tacit beliefs in a completely closed system of belief (like the one Stalnaker accepts in response to Kyburg's "one single fat statement" objection. Stalnaker embraces the idea that all our inductive knowledge could be represented by one fat statement because it makes for one very thin proposition. Wouldn't you also have to include your tacit beliefs into this huge conjuction? If you do not, then it seems incomplete, and if you do then you cannot avoid the problem of deduction. I think this is the biggest problem Stalnaker faces.