pragmatist comments on Mainstream Epistemology for LessWrong, Part 1: Feldman on Evidentialism - LessWrong

16 Post author: ChrisHallquist 16 November 2013 04:16PM

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Comment author: pragmatist 18 November 2013 01:08:00PM *  0 points [-]

The business of assigning probabilities presupposes that you can have some trust in induction, not that there has to be some platonic truth out there. Such a notion of truth is useless, because you can never establish what that truth is.

I don't know what you mean by "platonic truth". I suspect you are thinking of something much more metaphysically freighted than necessary. The kind of truth I'm talking about (and I think most people are talking about when they say "truth") very much can be established. For instance, I can establish what the truth is about the capital of Latvia by looking up Latvia on Wikipedia. I just did, and established the truth of the proposition "The capital of Latvia is Riga." Sure this doesn't establish the truth with 100% certainty, but why should that be the standard for truth being a useful notion?

Truth is not something you need God-like noumenal superpowers to determine. It's something that can be determined with the very human superpowers of empirical investigation and theory-building.

I'd say probability is more of an expression of your previous experiences, and how they can be used to predict what comes next.

I assign probabilities to past events, to empirically indistinguishable scientific hypotheses, to events that are in principle unobservable for me. Am I just doing it wrong, in your opinion?

That's what I mean, and that's what you would need if you think having that kind of a notion of truth is needed for probabilistic reasoning.

What kind of a notion of truth? The kind that requires absolute certainty? But I'm not aware of anyone arguing that one needs that kind of truth for the JTB account, or to make sense of probabilistic reasoning. Why do you think that kind of notion of truth is needed?

Comment author: hyporational 18 November 2013 01:14:08PM *  0 points [-]

I'm not arguing for any kind of notion of truth. I thought the kind of notion of truth JTB seems to be assuming is confusing as hell, and I wanted clarification for what it was trying to say.

My objection started from here:

2) You're misunderstanding the purpose of "true" in the JTB definition. It's not a matter of assigning probability 1 to a proposition, it's a matter of the proposition actually being true.

Can you get back to that, because I don't understand you anymore?

Comment author: pragmatist 18 November 2013 01:19:44PM *  1 point [-]

OK, I guess we were talking past each other. What is it about that particular claim that you find objectionable? I thought what you were objecting to was the notion that a proposition being true is distinct from it being assigned probability 1, and I was responding to that. But are you objecting to something else?

Is your objection just that you don't understand what people mean by "true" in the JTB account? I don't think they're committed to any particular notion, except for the claim that justification and truth are distinct. A belief can be highly justified and yet false, or not at all justified and yet true. Pretty much any of the theories discussed here would work. My personal preference is deflationism.

Comment author: hyporational 18 November 2013 01:36:02PM *  0 points [-]

ETA: I posted this also on the top of this comment thread, so you can answer there if you wish.

The way I read the quote is:

A proposition being true doesn't mean that it has the probability of 1. It does however mean that if a proposition is assigned a probability of 0.9, and it coincides with what the world is actually like, it is true.

This in turn could be read as:

A proposition being true doesn't mean that is has the probability of 1. It does however mean that if a proposition is assigned a probability of 0.9, and it coincides with what we know about the world with probability of 1, it is true.

Do you now understand my objection? I predict it's based on some grave misunderstanding. Thanks for the link, I'll try to check it out when I have more time.

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