The Problem of Forgotten Evidence

Among the things I know are things that I can’t remember where or how I learned them.

If that description is correct, does it follow that I now know things for which I have no evidence? Well, if I pick one of them (say, the claim that I spent quite a bit of my childhood on land that was deeded to the Souix in the treaty of 1852, a treaty altered unilaterally by the U.S. in 1868 in such a way that the land was no longer within Souix territory), I can say the following: my evidence is that I learned it somewhere, sometime; probably by reading it in a book.

But consider my state before reflecting on it. I’ve known for quite some time this fact. During this entire time, was I also aware that I learned it from a book? Did I, throughout the entire time that I’ve known this fact, believed that I learned it from a book? I doubt that this is true. But then it looks like I’m stuck: there are times that I knew this fact, but had no evidence for it. What I did have, however, was a disposition to form beliefs which have contents that support the content of the claim I know to be true. But how could such a disposition itself be evidence?


Comments

The Problem of Forgotten Evidence — 12 Comments

  1. Hi Jon,

    Right now, I know that there’s a computer in front of me. What is my evidence that there is a computer in front of me? Here’s a possible answer: I see it. (I see there to be a computer in front of me.)

    Also, right now, I know that Abraham Lincoln was assassinated in 1865. What is my evidence that Abraham Lincoln was assassinated in 1865? Here’s a possible answer: I remember it.

    Maybe those aren’t correct answers, but I’d need to hear why they’re not correct.

  2. Ram, yes, you’re right about this, that if you are allowed to use as evidence a claim that entails the claim in question there is no problem. For those that want a weaker notion of evidence, it’s hard to know what to say. (Which, I assume, you’ll like!).

  3. Jon,

    It seems that you’re going to get p justified by entailment from what you know in any case. Assume that we do know p in the forgotten evidence cases you describe. Let e be the evidence that justifies me in believing p. Even if I don’t know the content of e, I must know that (1) (Ee)(e justifies me in believing p). But then what I know (viz. (1)) entails that p is justified.
    If I don’t know (1)–if I don’t know that there is some evidence that justifies me in believing that p–then it’s harder to see how I know p in the forgotten evidence cases.

  4. Mike, I think your claims require too much reflection for knowledge, and knowledge by memory, to be present. If I’ve forgotten my evidence, in the ordinary case, I’ll retain the belief in question and if I knew it originally, I will, presumably, still know it. When I reflect on my knowledge, I’ll come to believe your principle (1). But I knew the claim prior to reflecting, and hence prior to taking any attitude at all toward (1).

  5. Realiblism. You learned that p in the past and your memory serves as a realible mechanism for knowing that p, even if you cannot remember how you learned that p.

    The latter is only a case in which you are not justified in believing that you learned that p by such and such or so and so. It is not (necessarily) a case in which you are not justified in believing that p.

  6. Ram, I’ve been thinking more about your proposal. I’m more worried about it now than I was originally. Here’s the worry. On the perceptual knowledge case, notice that you cite a mental state of the knower (or at least you cite something constituted in part by a mental state). To see the computer in front of you is to be in a relevant experiential state. It’s different from the state of believing, though they are presumably related causally.

    So now take your memorial knowledge. I know when Lincoln was assassinated. Do I remember it? Let’s suppose that the remembering is a mental state as well, or is composed in part by one. It won’t be identifiable with belief, though it may be related causally to belief.

    But this doesn’t sound plausible to me. Do I remember, if this is what remembering is. I would say that sometimes I remember and sometimes not, though if asked to explain why I think Lincoln was assassinated, I’ll then be in a mental state accurately reportable by saying that I remember it. But that state, it seems to me, comes and goes, just as my perceptual state of seeing a computer screen in front of me comes and goes.

    What doesn’t come and go, it seems to me, is (pardon waxing metaphoric here) the location of the information about Lincoln. It’s always located in my memory box. I don’t see how that gives me any evidence, when I’m not remembering, that Lincoln was assassinated.

  7. _I would say that sometimes I remember and sometimes not, though if asked to explain why I think Lincoln was assassinated, Iâ??ll then be in a mental state accurately reportable by saying that I remember it_.

    This can’t be right. Why would you say that you don’t remember the date on which Lincoln was assassinated until you are in the state of having recalled the date on which Lincoln was assassinated? If I ask you whether you remember the pledge of allegiance, the answer is surely yes long before you are in the state of having recalled the words. The answer in this case is not going to be “let me see if I remember, I pledge…”. (If that is your answer in this case, I’ll ask you whether you remember the words to some well-known nursery rhyme or something). If I ask you whether you remember how to get to Chicago, the answer can correctly be “yes” long before you have the exact route before your mind.

  8. Mike, of course, when asked, I’ll say I remember. The question is whether, when not being asked and not thinking about the matter at all, I’m in a state of remembering. That’s not obvious; in fact, I think it is false if remembering is an experiential state like perceiving.

    If remembering is conceived of differently, as a kind of mental box akin to the belief box, then this worry subsides a bit. What it is for a belief to be justified by memory is for the same content to be in both boxes. If that’s right, then memory and experience work quite differently. Experience is episodic, with belief the more persistent “residue” left behind by (some) experience. Here, memory isn’t the episodic sort, but the enduring sort. Memory states would then, presumably, also be the more persistent “residue” left behind by experience as well.

    My concern about this story is the multiplication of boxes serving as the containers for the residue of experience. But that’s not an argument, just the expression of a vague dis-ease…

  9. _… of course, when asked, Iâ??ll say I remember. The question is whether, when not being asked and not thinking about the matter at all, Iâ??m in a state of remembering. Thatâ??s not obvious; in fact, I think it is false if remembering is an experiential state like perceiving_.

    Jon, I guess I don’t see it. Here is a simple example. I ask you “do you remember the way to the University?” and you say truly “yes”. But answering truly “yes” does not depend on *any* change in your mental or experiential state. It seems phenomenologically mistaken. I can correctly answer “yes, I know the way to the University” without any interesting change in my mental state. I can answer yes to that question when I am occupied with something else entirely. This happens to everyone when questions concern things they do all of the time. So my mental state prior to being asked the question and my mental state after being asked the question don’t seem to explain why I remember in one case and not (or, perhaps not) in the other.

  10. Mike, you’re not addressing the crucial point in what you quoted, about whether remembering is an (episodic) experiential state like perceiving. If not, then there is a different issue (the multiplicity of residue boxes), as I raised in the second paragraph. Moreover, your response waffles between remembering and knowing, but it was never in question whether knowing is an episodic experiential state.

  11. Jon, I thought I denied that remembering that was analogous to perceiving. I thought I said that you can truly say “yes, I remember the way to the University” without having any interesting change in your mental states. Further I thought I said that claiming that there must be such a change (as there certainly would be were remembering analogous to perceiving) seems phenomenologically mistaken. So, yes, I am denying that remembering is episodic, unlike perception. I say that because it seems to me pretty well-confirmed, if noticing no change in mental states in such cases is evidence that there is none. Suppose that’s right. Does the issue then turn to “the multiplicity of residue boxes”? I doubt it. That is just *one* alternative hypothesis. No doubt the issue then turns to *some* alternative hypothesis. But I’m not certain which.
    On the issue of “waffling” between knowing and remembering, you’re exactly right. I inadvertently did that. But nonetheless I did it. You can read the post substituting ‘remember’ for ‘know’ and the point is the same.

  12. So suppose remembering is not episodic, that ever since you learned by experience that p you’ve been in the state of remembering that p. Ever since you’ve learned that, you’ve also believed that p, and, we can assume, known that p. So, taking away the metaphorical part of my talk of “residue boxes,” the alternative to the episodic view is as I described it: there will have to be multiple persistent mental states in place.

    That may be the correct view, but it is puzzling. We can explain why believings are persistent states: we need them to explain actions. But if we have beliefs being the persistent residue of experience (and other things), there’s no need for persistent states of remembering. The only thing I see for them to do is to sustain evidentialism: they are the evidence that continually makes reasonable the believings.

    Maybe they cause the continuation of the believings, too? That may be a role for them to play, but if we have anything like inertial principles in our explanatory system, it’s hard to see why we need the rememberings for this.

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