lukeprog comments on The Useful Idea of Truth - Less Wrong

77 Post author: Eliezer_Yudkowsky 02 October 2012 06:16PM

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Comment author: Eliezer_Yudkowsky 02 October 2012 05:28:00AM 23 points [-]

(The 'Mainstream Status' comment is intended to provide a quick overview of what the status of the post's ideas are within contemporary academia, at least so far as the poster knows. Anyone claiming a particular paper precedents the post should try to describe the exact relevant idea as presented in the paper, ideally with a quote or excerpt, especially if the paper is locked behind a paywall. Do not represent large complicated ideas as standard if only a part is accepted; do not represent a complicated idea as precedented if only a part is described. With those caveats, all relevant papers and citations are much solicited! Hopefully comment-collections like these can serve as a standard link between LW presentations and academic ones.)

The correspondence theory of truth is the first position listed in the Stanford Encyclopedia of Philosophy, which is my usual criterion for saying that something is a solved problem in philosophy. Clear-cut simple visual illustration inspired by the Sally-Anne experimental paradigm is not something I have previously seen associated with it, so the explanation in this post is - I hope - an improvement over what's standard.

Alfred Tarski is a famous mathematician whose theory of truth is widely known.

The notion of possible worlds is very standard and popular in philosophy; some of them even ascribe much more realism to them than I would (since I regard them as imaginary constructs, not thingies that can potentially explain real events as opposed to epistemic puzzles).

I haven't particularly run across any philosophy explicitly making the connection from the correspondence theory of truth to "There are causal processes producing map-territory correspondences" to "You have to look at things in order to draw accurate maps of them, and this is a general rule with no exception for special interest groups who want more forgiving treatment for their assertions". I would not be surprised to find out it existed, especially on the second clause.

Added: The term "post-utopian" was intended to be a made-up word that had no existing standardized meaning in literature, though it's simple enough that somebody has probably used it somewhere. It operates as a stand-in for more complicated postmodern literary terms that sound significant but mean nothing. If you think there are none of those, Alan Sokal would like to have a word with you. (Beating up on postmodernism is also pretty mainstream among Traditional Rationalists.)

You might also be interested in checking out what Mohandas Gandhi had to say about "the meaning of truth", just in case you were wondering what things are like in the rest of the world outside the halls of philosophy departments.

Comment author: lukeprog 02 October 2012 06:24:00AM *  11 points [-]

Speaking as the author of Eliezer's Sequences and Mainstream Academia...

Off the top of my head, I also can't think of a philosopher who has made an explicit connection from the correspondence theory of truth to "there are causal processes producing map-territory correspondences" to "you have to look at things to draw accurate maps of them..."

But if this connection has been made explicitly, I would expect it to be made by someone who accepts both the correspondence theory and "naturalized epistemology", often summed up in a quote from Quine:

The stimulation of his sensory receptors is all the evidence anybody has had to go on, ultimately, in arriving at his picture of the world. Why not just see how this construction really proceeds? Why not settle for psychology? ...Epistemology, or something like it, simply falls into place as a chapter of psychology and hence of natural science.

(Originally, Quine's naturalized epistemology accounted only for this descriptive part of epistemology, and neglected the normative part, e.g. truth conditions. In the 80s Quine started saying that the normative part entered into naturalized epistemology through "the technology of truth-seeking," but he was pretty vague about this.)

Edit: Another relevant discussion of embodiment and theories of truth can be found in chapter 7 of Philosophy in the Flesh.

Comment author: ciphergoth 02 October 2012 07:50:54AM 11 points [-]

Off the top of my head, I also can't think of a philosopher who has made an explicit connection from the correspondence theory of truth to "there are causal processes producing map-territory correspondences" to "you have to look at things to draw accurate maps of them..."

OK, I defended the tweet that got this response from Eliezer as the sort of rhetorical flourish that gets people to actually click on the link. However, it looks like I also underestimated how original the sequences are - I had really expected this sort of thing to mirror work in mainstream philosophy.

Comment author: DuncanS 04 October 2012 11:02:46PM *  2 points [-]

Although I wouldn't think of this particular thing as being an invention on his part - I'm not sure I've read that particular chain of thought before, but all the elements of the chain are things I've known for years.

However I think it illustrates the strength of Eliezer's writing well. It's a perfectly legitimate sequence of thought steps that leads in a clear and obvious way to the right answer. It's not new thought, but a particularly clear way of expressing something that many people have thought and written about in a less organised way.

To clarify - there are times when Eliezer is inventive - for example his work on CEV - but this isn't one of those places. I know I'm partly arguing about the meaning of "inventive", but I don't think we're doing him a favor here by claiming this is an example of his inventiveness when there are much better candidates.

Comment author: MichaelVassar 02 October 2012 07:16:36PM 13 points [-]

It's not that clear to me in what sense mainstream academia is a unified thing which holds positions, even regarding questions such as "what fields are legitimate". Saying that something is known in mainstream academia seems suspiciously like saying that "something is encoded in the matter in my shoelace, given the right decryption schema. OTOH, it's highly meaningful to say that something is discoverable by someone with competent 'google-fu"

Comment author: lukeprog 03 October 2012 10:55:20AM 0 points [-]

Agree with all this.

Comment author: DaFranker 03 October 2012 01:26:06PM 0 points [-]

It's not that clear to me in what sense mainstream academia is a unified thing which holds positions, even regarding questions such as "what fields are legitimate".

Strongly seconded.

Hell, some "Mainstream" scientists are working on big-money research project that attempt to prove that there's a worldwide conspiracy attempting to convince people that global warming exists so as to make money off of it. Either they're all sell-outs, something which seems very unlikely, or at least some of them actually disagree with some other mainstream scientists, who see the "Is there real global warming?" question as obviously resolved long ago.

Comment author: betterthanwell 04 October 2012 10:53:49PM *  0 points [-]

I also can't think of a philosopher who has made an explicit connection from the correspondence theory of truth to "there are causal processes producing map-territory correspondences" to "you have to look at things to draw accurate maps of them..."

Karl Popper did so explicitly, thoroughly and convincingly in The Logic of Scientific Discovery. Pretty influential, and definitely a part of "Mainstream Academia."

Here's an interesting, if lengthy, footnote to Chapter 84 - Remarks Concerning the use of the concepts 'True' and 'Corroborated'.

(1) Not long after this was written, I had the good fortune to meet Alfred Tarski who explained to me the fundamental ideas of his theory of truth. It is a great pity that this theory—one of the two great discoveries in the field of logic made since Principia Mathematica—is still often misunderstood and misrepresented. It cannot be too strongly emphasized that Tarski’s idea of truth (for whose definition with respect to formalized languages Tarski gave a method) is the same idea which Aristotle had in mind and indeed most people (except pragmatists): the idea that truth is correspondence with the facts (or with reality). But what can we possibly mean if we say of a statement that it corresponds with the facts (or with reality)? Once we realize that this correspondence cannot be one of structural similarity, the task of elucidating this correspondence seems hopeless; and as a consequence, we may become suspicious of the concept of truth, and prefer not to use it. Tarski solved (with respect to formalized languages) this apparently hopeless problem by making use of a semantic metalanguage, reducing the idea of correspondence to that of ‘satisfaction’ or ‘fulfilment’. As a result of Tarski’s teaching, I no longer hesitate to speak of ‘truth’ and ‘falsity’. (...)

A (short) footnote of my own: Popper's writings have assumed the status of mere "background knowledge", which is a truly great achievement for any philosopher of science. However, The Logic of Scientific discovery is a glorious book which deserves to be even more widely read. Part I of the book spans no more than 30 pages. It's nothing short of beautiful. PDF here.

Comment author: lukeprog 05 October 2012 05:15:41AM 2 points [-]

Could you please quote the part of Popper's book that makes the explicit connection from the correspondence theory of truth to "there are causal processes producing map-territory correspondences" to "you have to look at things to draw accurate maps of them..."?

Comment author: betterthanwell 05 October 2012 10:38:46AM *  0 points [-]

Could you please quote the part of Popper's book that makes the explicit connection from the correspondence theory of truth to "there are causal processes producing map-territory correspondences" to "you have to look at things to draw accurate maps of them..."?

Right, this is the obvious next question. I started looking for the appropriate "sound bites" yesterday, but encountered a bit of difficulty in doing so, as I shall explain. Popper's embrace of (Tarskian) correspondence theory should be at least somewhat clear from the footnote I quoted above.

It seems clear to me, from my recount of the book that "you have to look at things to draw accurate maps of them" is one of the chief aims, and one of the central claims of the book; a claim which is defended, by a lengthy, but quite convincing and unusually successful argument - the premises to which are presented only one at a time, and quite meticulously over at least several chapters, so I'm not exactly sure how to go about quoting only the "relevant parts".

My claim that his argument was convincing and successful, is based on the historical observation that popperian falsificationism (the hypothetico-deductive framework) won out over the then quite prevalent logical positivist / verificationist view, to such an extent that it quickly became the default mode of Science, a position it has held, mostly uncontested, ever since, and therefore is barely worthy of mention today. Except when it is, that is; when one encounters problems that are metaphysical (according to Popper), such as Susskind's String Landscape of perhaps 10^500 vacuua, the small (but significant) observed value of the cosmological constant, the (seemingly fine tuned) value of the fine structure constant, and other observations that may require anthropic i.e. metaphysical explanations, since these problems are seemingly not decidable inside of standard, i.e. popperian science.

I feel faced with a claim similar to "I don't believe any mathematician has convincingly proven Fermat's last theorem." To which I reply: Andrew Wiles (1995) The obvious next question is: "Can you please quote the part where he proves the theorem?" This is unfortunately somewhat involved, as the entire 109 page paper tries and succeds at doing so around as concisely as Wiles himself managed to go about it. Unfortunately, in the Popper case, I cannot simply provide the relevant Wikipedia Article and leave it at that.

I suppose that having made the claim, it is only my duty to back it up, or else concede defeat. If you're still interested, I shall give it a thorough look, but will need a bit of time to do so. Hopefully, you'll have my reply before monday.

Comment author: betterthanwell 05 October 2012 11:09:51AM *  0 points [-]

A (very) quick attempt, perhaps this will suffice? (Let me know if not. )

I begin with the tersest possible defense of my claim that Popper argued that "you actually have to look at things to draw accurate maps of them...", even though this particular example is particularily trivial:

Page 19:

(Thus the statement, ‘It will rain or not rain here tomorrow’ will not be regarded as empirical, simply because it cannot be refuted; whereas the statement, ‘It will rain here tomorrow’ will be regarded as empirical.)

To paraphrase: You have to look actually out the window to discover whether it is raining or not.

Continuing, page 16:

The task of formulating an acceptable definition of the idea of an ‘empirical science’ is not without its difficulties. Some of these arise from the fact that there must be many theoretical systems with a logical structure very similar to the one which at any particular time is the accepted system of empirical science. This situation is sometimes described by saying that there is a great number—presumably an infinite number— of ‘logically possible worlds’. Yet the system called ‘empirical science’ is intended to represent only one world: the ‘real world’ or the ‘world of our experience’.*1

Various objections might be raised against the criterion of demarcation here proposed. In the first place, it may well seem somewhat wrong-headed to suggest that science, which is supposed to give us positive information, should be characterized as satisfying a negative requirement such as refutability. However, I shall show, in sections 31 to 46, that this objection has little weight, since the amount of positive information about the world which is conveyed by a scientific statement is the greater the more likely it is to clash, because of its logical character, with possible singular statements. (Not for nothing do we call the laws of nature ‘laws’: the more they prohibit the more they say.)

My proposal is based upon an asymmetry between verifiability and falsifiability; an asymmetry which results from the logical form of universal statements.*4 For these are never derivable from singular statements, but can be contradicted by singular statements. Consequently it is possible by means of purely deductive inferences (with the help of the modus tollens of classical logic) to argue from the truth of singular statements to the falsity of universal statements. Such an argument to the falsity of universal statements is the only strictly deductive kind of inference that proceeds, as it were, in the ‘inductive direction’; that is, from singular to universal statements. *4 This asymmetry is now more fully discussed in section *22 of my Postscript.

(Oops, comment too long.)

Comment author: betterthanwell 05 October 2012 11:10:23AM *  0 points [-]

(Continued)

Page 20:

According to my proposal, what characterizes the empirical method is its manner of exposing to falsification, in every conceivable way, the system to be tested. Its aim is not to save the lives of untenable systems but, on the contrary, to select the one which is by comparison the fittest, by exposing them all to the fiercest struggle for survival.

[a number of indicative, but not decisive quotes omitted]

I had hoped to find some decisive sound bite in part one, which is a brief discussion of the epistemological problems facing any theory of scientific method, and an outline of Popper's framework, but it looks like I shall have to go deeper. Will look into this over the weekend.

I also found another, though much more recent candidate, David Deutsch in The Beginning of Infinity, Chapter 1 on "The Reach of Explanations". Tough I'm beginning to suspect that although they both point out that "you have to look at things to draw accurate maps of them...", and describe "causal processes producing map-territory correspondences" (for example, between some state of affairs and the output of some scientific instument) both Deutsch and Popper seem to have omitted what one may call the "neuroscience of epistemology." (Where the photon reflects off your shoelace, gets absorbed by your retina, leading to information about the configuration of the world becoming entangled with some corresponding state of your brain, and so on.) This is admittedly quite a crucial step, which Yudkowsky's explanation does cover, and which I cannot recall to have seen elsewhere.

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