I am not claiming that this theory is correct. But it seems to generate all the right normative predictions. Observe that there is no way to reduce the illocutionary force of promises to that of assertions. To promise is not just to assert that one will do something or that one intends to do something or anything like that. But there appears to be a way to reduce the illocutionary force of assertions to that of promises.
I can promise to do all sorts of things For instance, I can promise to raise my right hand only when my left ear itches. Among the things I can promise is the making of an utterance. For instance, I can promise that I will only utter "I am bored" on Saturday afternoons. I shall use "utter" in a way that does not imply assertion: when one asserts "I am bored", one also utters it, but one can utter it without asserting it. One can utter it in denial. (A: Tell me something false. B: I am bored.) One can utter it as an example of a sentence when teaching a language. One can utter it on stage. Etc.
The basic theory is that the normative effect of asserting s is exactly the same as the normative effect of:
- I promise to next utter only something true. s.
If you are drawn to belief, justified belief or knowledge norms of assertion, replace "true" with "believed by me", "justifiedly believed by me" or "known by me" in (1). This will lose you some of what the theory can do for you, but it may still be a better theory than other theories of assertion.
The promise theory of assertion explains why it's typically morally wrong to assert something one doesn't believe. For if one doesn't believe that s is true, in making the promise in (1) while intending it to be followed by s, one is making a promise that one intends to break. Thus, we also get a reduction of the moral wrongness of lying to the moral wrongness of insincere promising.
Next consider retraction. Here it matters that we have "true" instead of one of the doxastic or epistemic things in (1). Observe that there are multiple kinds of cases where an apology is called for in a promise, including these:
- I promised to A, never intending to A.
- I promised to A, I failed to A, and I was culpable because I was not justified in believing that I was in fact Aing when I wasn't.
- I promised to A, I failed to A, but I wasn't culpable because I justifiedly believed that I was in fact Aing when I wasn't.
- I promised to A, and then I acted in a way that I didn't know was fulfillment of the promise.
- I promised to A, I did A, but I shouldn't have promised or done A, because promising and doing A was bad for some other reason.
- I asserted "s", not intending to assert something true. (This divides into two subtypes. On one subtype, I intended to assert something that I believed false—this correponds to intending to do something that one believes to be a breaking of the promise while making the promise. On the other subtype, I simply didn't care about truth and falsity, which is BS, and that corresponds to simply failing to intend to keep the promise one is making.)
- I asserted "s", but "s" was false, and I was culpable because I was not justified in believing that "s" is true.
- I asserted "s", but "s" was false, but I wasn't culpable because I was justified in believing that "s" is true.
- I asserted "s", but I didn't know that "s" was true.
- I asserted "s", but I shouldn't have said "s", even though "s" is true, but I shouldn't have asserted "s", because asserting "s" was bad for some other reasons. (E.g., it was the revealing of privileged information.)
Dan Johnson points out to me that the above lets one accommodate the insights behind norms of assertion other than truth, by giving a variety of modes of assertion failure, which modes fit with the failure to act in accordance with these modified norms. I don't think one can do this if one replaces "true" in (1) with anything epistemic, so (1) with "true" is the best version.
Here now is an interesting consequence. If someone I justifiedly trust promises to do something, I have reason to believe that she will do it. The present account implies that if someone I justifiedly trust asserts something, I have reason to believe that the assertion is true. For she has promised to utter only something true, and so when I learn that she has uttered "s", I have reason to believe that "s" is true. So trust in testimony reduces to trust in promises.
The account predicts that just as there are varying strengths of promises, there will be strengths of assertion. This prediction is borne out. Further analysis is needed to see how to flesh out the parallel strengths. And we can take the colloquial form of assertion "I promise you that p" as a shorthand for a stronger version of (1).
Likewise, denial can be handled very similarly: a denial involves a promise to utter something false.