Klein on Useful Falsehoods II

Here’s a further issue for Klein’s account of useful falsehoods. For reference, here’s the full account again:

The belief that uf is a useful falsehood to S (for acquiring knowledge) by producing a
doxastically justified belief that h iff:
1. uf is false
2. The belief that uf is doxastically justified for S
3. The belief that uf is essential in the causal production of the belief that h
4. uf propositionally justifies h
5. uf entails a true proposition, t
6. t propositionally justifies h
7. Whatever doxastically justifies the belief that uf for S also propositionally
justifies t for S.

According to the above account, whatever justifies the false belief has to justify the true proposition as well, and both the true proposition and the false belief have to justify the piece of knowledge in question. Suppose we left the account there, expunging clause 5 altogether. Are there cases in which this elimination causes a problem? Another way to put this question is as follows. Klein develops his account to honor Hilpinen’s remark about being close to the truth, and alethic presupposition is one way of clarifying that idea. But why can’t being close to the truth be taken only in terms of being justified by the same evidence, both the useful falsehood and the truth that is explanatorily operative when we say why the inferred belief counts as knowledge? The idea is that the useful falsehood is close to the truth simply in virtue of being evidenced by precisely the same evidence that justifies the truth in question.

Here’s a variant of a case Matt McGrath raised in conversation. Suppose a person reasons through a false theory to a true conclusion, on the basis of evidence that actually confirms good reasons for believing the true theory. To be specific, suppose the bull in front of you is snorting and pawing the ground. Seeing this is evidence for you that he’s about to charge, and that’s evidence for you that you should get as far away as possible. The false theory in question is some animistic conception of things according to which an evil spirit has possessed the bull, and since the spirit is evil, one should get as far away as possible.

In such a case, there is no entailment relationship between the claim that the animistic claim and the claim that the bull is about to charge. Is there an epistemic relation? That is, does the belief that there is an evil spirit possessing the body of the bull justify (for the person in question) the claim that the bull is about to charge? I’m inclined to say that in some cases it will, and in some cases it won’t, but that it doesn’t much matter. If this point is correct, then a false belief can be useful for the acquisition of knowledge even if the story as to why knowledge is acquired appeals to truths that bear no logical or epistemic relation to the falsehood in question.


Klein on Useful Falsehoods II — 3 Comments

  1. Okay. One last comment — then back to papers.

    I agree with Jon that perhaps the relationship between the useful falsehood and the true proposition might be an epistemic one rather than some form of relevant entailment (because in each case I have thought of both seem to apply — perhaps because relevant entailment is an epistemic notion anyway?); but I’m not certain that the bull case does establish that. In that case the falsehood is this: the bull has been possessed by an evil spirit that will cause it to charge. (I suppose that the signs of spirit possession are the pawing, snorting and other such things.) But I think I should take advantage of the way that Jon sees my account as indicated in the other posting having to do with the Ptolemaic astronomer and the astrologer case. In those cases, he thought (correctly I think) that my account would have it that both the astronomer and the astrologer knew [remember that in this fictional case, the astrologer’s predictions are as accurate as the astronomer’s and presumably satisfy some subjective conditionals like “if the astrologer were to predict that Carey will grow up to be wiser than Bush, then Carey will grow up to be wiser than Bush” — otherwise there will be lots of defeaters] had knowledge. I think the animist has knowledge if his predictions are as good as the astronomer’s â�� and presumably they are. The true proposition entailed by the useful falsehood is that bulls act just as though they are possessed by evil spirits that cause them to charge whenever they snort, paw, etc.

    Now, just for the record, I don’t think its always the entailment that instrumentalists would point to that are the most natural to think of in cases of useful falsehoods. I presented four such cases for discussion in the paper that I gave at Missouri. Here they are:

    First Case (The Appointment Case): I believe that my secretary told me on Friday that I have an appointment on Monday with a student. From that belief, I infer that I do have an appointment on Monday. Suppose further, that I do have an appointment on Monday, and that my secretary told me so. But she did not tell me that on Friday — she told me that on Thursday. I know that I have such an appointment even though I inferred it from the false proposition that my secretary told me on Friday that I have an appointment on Monday.

    Second Case (The Santa Claus Case): Mom and Dad tell young Virginia that Santa will put some presents under the tree on Christmas Eve. Believing what her parents told her, she infers that there will be presents under the tree on Christmas morning. She knows that.

    Third Case (The Average Rainfall Case): Weatherman believes that the average annual precipitation in Northwest Montana is about 13 inches because he believes that accurate records have been kept for over 80 years and the rainfall depicted in the number of years that records were kept averages to 13 inches. The average rainfall is about 13 inches but accurate records were only kept for 79 years. Weatherman knows that the average rainfall is about 13 inches. [Note: This case is similar to one presented by Risto Hilpinen in “Knowledge and Conditionals,” op. cit., 163-4.]

    Fourth Case (The Ptolemaic Astronomer Case): The date is September 2, 1203; the place is Oxford University. An astronomy class is in session and the instructor, one of the most noted Ptolemaic Astronomers of the 13th century, is showing students how to calculate the relative positions of the sun and planets both backward and forward in time using the deferent and epicycle orbits of those bodies and their (then) current positions. After explaining the method carefully, he asks the students to determine whether Mars will be visible from the earth 800 years later, supposing, of course, that it’s not cloudy that night. They enter the (then) current relative positions of the sun, Mars and earth as they believe them to be according to Ptolemaic Astronomy and extrapolate using the method just learned. They conclude that, ceteris paribus, Mars will be visible on September 2, 2003. On the assumption that the assigned orbits and then-current relative positions of the three bodies allow for sufficiently accurate extrapolations, the students know that Mars will be visible on September 2, 2003, even though their beliefs are based upon false beliefs about the fixed position of the earth and the orbits of the sun and Mars.

    And here are the true propositions entailed by the useful falsehoods and what they propositionally justify. Only the last one strikes me as “instrumentalist” although I suppose with some interesting chisholming we could turn them all into the instrumentalist variety:

    First Case: My secretary told me that I have an appointment on Monday propositionally justifies I have an appointment on Monday.

    Second Case: Someone will put a present under the tree on Christmas Eve propositionally justifies there will be a present under the tree on Christmas morning.

    Third Case: Accurate annual rainfall records were kept for 79 years and the rainfall depicted in the number of years that records were kept averages to 13 inches propositionally justifies the average annual rainfall is 13 inches.

    Fourth Case: The relative positions of the sun, Mars and earth are such that they repeat in a predictable manner just as if Ptolemaic Astronomy were correct propositionally justifies Mars will be visible on September 2, 2003.

  2. That’s good, Peter; I hadn’t seen the bull case as just a variant on the other case, but now I think you’re right that it is. I worry a bit about relying on the falsity of subjunctive conditionals to be the defeaters needed, however, though I don’t have much of an argument. Here’s the worry. For a true theory and an accurate prediction, I think we’ll find a sequence of subjunctive conditionals, some true some false, with greater amounts of information in the antecedent (and all including the actual grounds of the prediction). The s.c. with the maximal and complete antecedent will be true, but that won’t show that there are no defeaters. So, the defeasibility theorist who wishes to appeal to s.c.’s will have to say which of the s.c.’s are relevant to the question of whether there is a genuine defeater, and I don’t know how to do that. Maybe you have some ideas, though? This problem looks to me like the generality problem in a different context…

  3. Pingback: Certain Doubts » Testimony, Lies, Fiction and Benign Falsehoods

Leave a Reply

Your email address will not be published. Required fields are marked *