pragmatist

Karma: 4,966

pragmatist 24 Jul 2014 17:58 UTC
65 points
on: Jokes Thread
Moral Philosopher: How would you characterize irrational behavior?

Economist: When someone acts counter to their preferences.

Moral Philosopher: Oh, that’s what we call virtue.

pragmatist 12 Jul 2014 8:11 UTC
60 points
on: “Dialectics”?

The LW survey says about 1 in 4 of us is a communist

No, it doesn’t. In the last LW survey, 0.7% of respondents identified as communists. Perhaps you’re talking about the 30% that identified as “socialist”? But “socialism” in the survey was defined as support for a highly redistributive, socially permissive political regime, like they have in Scandinavian countries. That doesn’t imply allegiance to Marxist doctrine, or knowledge of it.

As for the idea of “dialectic”, Marx got it from Hegel, and a full understanding of Hegel—if it is possible at all—is not something that can be effectively communicated in a comment or short internet article, I think (this might help, but probably not). As a rough approximation, though, the dialectical method is basically just systems thinking.

It’s presented as an alternative to the analytical method, which involves breaking a system down into parts and attempting to understand each part individually. The idea governing analytical thinking (says the proponent of dialectic) is that the intrinsic nature of the parts can be understood prior to figuring out how they fit together to form the whole.

Dialectical thinking, on the other hand, is based on the idea that the concrete nature of the parts cannot be understood without understanding the role they play in the whole, the relationships between them. So the analytic project, which focuses first on understanding parts considered individually, is doomed to failure, because it ignores the extent to which the overall context is essential for our understanding of the nature of the parts.

“Dialectical materialism” in Marxist thought is basically just an application of this dialectical thinking to economics. One could approach economics analytically by first, say, constructing a model of individual economic agents, and then trying to figure out what happens when these agents interact under certain conditions. The proponent of the dialectical method (like Marx) would, however, insist that this is mistaken. Human nature and human needs cannot be understood in isolation. They are a product of the socio-economic context, just as the socio-economic context is itself a product of human nature and needs, and the individual elements and overall context are constantly changing in response to one another. So to truly understand the dynamics of the economy, you need to approach it from a systems perspective. You need to start by understanding the historical dynamics of the interactions and relationships between elements of the system and how that effects the evolution of the natures of those elements, rather than starting with a static model of the individual elements and only then moving to an analysis of their interactions. The natures of individual elements are constituted by their participation in the system, and they change as the system evolves, so you shouldn’t treat those individual natures as logically prior to the system.

So that’s a quick and clumsy attempt at explicating what the dialectic method is all about. As for whether the method is useful: There is something right about the idea that focusing purely on the analytical method can lead to mistakes, but a complete repudiation of this very useful pattern of reasoning also seems to be a mistake. It seems to me that the dialectical method (and systems thinking in general) should be regarded as a useful complement (and often corrective) to analytical thinking, but not as a wholesale replacement.

pragmatist 7 Jun 2012 23:27 UTC
60 points
on: Debate between 80,000 hours and a socialist
Here’s an attempted reconstruction of Mills’ argument. I’m not endorsing this argument (although there are parts of it with which I sympathize), but I think it is a lot better than the case for Mills as you present it in your post:

If a friend asked me whether she should vote in the upcoming Presidential election, I would advise her not to. It would be an inconvenience, and the chance of her vote making a difference to the outcome in my state is minuscule. From a consequentialist point of view, there is a good argument that it would be (mildly) unethical for her to vote, given the non-negligible cost and the negligible benefit. So if I were her personal ethical adviser, I would advise her not to vote. This analysis applies not just to my friend, but to most people in my state. So I might conclude that I would encourage significant good if I launched a large-scale state-wide media blitz discouraging voter turn-out. But this would be a bad idea! What is sound ethical advice directed at an individual is irresponsible when directed at the aggregate.

80k strongly encourages professional philanthropism over political activism, based on an individualist analysis. Any individual’s chance of making a difference as an activist is small, much smaller than his chance of making a difference as a professional philanthropist. Directed at individuals, this might be sound ethical advice. But the message has pernicious consequences when directed at the aggregate, as 80k intends.

It is possible for political activism to move society towards a fundamental systemic change that would massively reduce global injustice and suffering. However, this requires a cadre of dedicated activists. Replaceability does not hold of political activism; if one morally serious and engaged activist is lured away from activism, it depletes the cadre. Now any single activist leaving (or not joining) the cadre will not significantly affect the chances of revolution succeeding. But if there is a message in the zeitgeist that discourages political participation, instead encouraging potential revolutionaries to participate in the capitalist system, this can significantly impact the chance of revolutionary success. So 80k’s message is dangerous If enough motivated and passionate young people are convinced by their argument.

It’s sort of like an n-person prisoner’s dilemma, where each individual’s (ethically) dominant strategy is to defect (conform with the capitalist system and be a philanthropist), but the Nash equilibrium is not the Pareto optimum. This kind of analysis is not uncommon in the Marxist literature. Analytic Marxists (like Jon Elster) interpret class consciousness as a stage of development at which individuals regard their strategy in a game as representative of the strategy of everyone in their socio-economic class. This changes the game so that certain strategies which would otherwise be individually attractive but which lead to unfortunate consequences if adopted in the aggregate are rendered individually unattractive. [It’s been a while since I’ve read this stuff, so I may be misremembering, but this is what I recall.]
What links here?

pragmatist 26 Sep 2012 15:16 UTC
53 points
on: [Poll] Less Wrong and Mainstream Philosophy: How Different are We?
I’ve posted brief explanations for some of the questions as replies to those questions. I haven’t posted explanations for those questions that I believe the vast majority of LW users will understand. If you don’t understand a question, I’m fairly certain that if you scroll down far enough you’ll find a comment from me with an attempt at explication.

pragmatist 2 Oct 2012 21:36 UTC
48 points
in reply to: Eliezer Yudkowsky’s comment on: The Useful Idea of Truth
This is a great post. I think the presentation of the ideas is clearer and more engaging than the sequences, and the cartoons are really nice. Wild applause for the artist.

I have a few things to say about the status of these ideas in mainstream philosophy, since I’m somewhat familiar with the mainstream literature (although admittedly it’s not the area of my expertise). I’ll split up my individual points into separate comments.

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

Summary of my point: Tarski’s biconditionals are not supposed to be a definition of truth. They are supposed to be a test of the adequacy of a proposed definition of truth. Proponents of many different theories claim that their theory passes this test of adequacy, so to identify Tarski’s criterion with the correspondence theory is incorrect, or at the very least, a highly controversial claim that requires defense. What follows is a detailed account of why the biconditionals can’t be an adequate definition of truth, and of what Tarski’s actual theory of truth is.

Describing Tarski’s biconditionals as a definition of truth or a theory of truth is misleading. The relevant paper is The Semantic Conception of Truth. Let’s call sentences of the form ‘p’ is true iff p T-sentences. Tarski’s claim in the paper is that the T-sentences constitute a criterion of adequacy for any proposed theory of truth. Specifically, a theory of truth is only adequate if all the T-sentences follow from it. This basically amounts to the claim that any adequate theory of truth must get the extension of the truth-predicate right—it must assign the truth-predicate to all and only those sentences that are in fact true.

I admit that the conjunction of all the T-sentences does in fact satisfy this criterion of adequacy. All the individual T-sentences do follow from this conjunction (assuming we’ve solved the subtle problem of dealing with infinitely long sentences). So if we are measuring by this criterion alone, I guess this conjunction would qualify as an adequate theory of truth. But there are other plausible criteria according to which it is inadequate. First, it’s a frickin’ infinite conjunction. We usually prefer our definitions to be shorter. More significantly, we usually demand more than mere extensional adequacy from our definitions. We also demand intensional adequacy.

If you ask someone for a definition of “Emperor of Rome” and she responds “X is an Emperor of Rome iff X is one of these...” and then proceeds to list every actual Emperor of Rome, I suspect you would find this definition inadequate. There are possible worlds in which Julius Caesar was an Emperor of Rome, even though he wasn’t in the actual world. If your friend is right, then those worlds are ruled out by definition. Surely that’s not satisfactory. The definition is extensionally adequate but not intensionally adequate. The T-sentence criterion only tests for extensional adequacy of a definition. It is satisfied by any theory that assigns the correct truth predicates in our world, whether or not that theory limns the account of truth in a way that is adequate for other possible worlds. Remember, the biconditionals here are material, not subjunctive. The T-sentences don’t tell us that an adequate theory would assign “Snow is green” as true if snow were green. But surely we want an adequate theory to do just that. If you regard the T-sentences themselves as the definition of truth, all that the definition gives us is a scheme for determining which truth ascriptions are true and false in our world. It tells us nothing about how to make these determinations in other possible worlds.

To make the problem more explicit, suppose I speak a language in which the sentence “Snow is white” means that grass is green. It will still be true that, for my language, “Snow is white” is true iff snow is white. Yet we don’t want to say this biconditional captures what it means for “Snow is white” to be true in my language. After all, in a possible world where snow remained white but grass was red, the sentence would be false.

Tarski was a smart guy, and I’m pretty sure he realized all this (or at least some of it). He constantly refers to the T-sentences as material criteria of adequacy for a definition of truth. He says (speaking about the T-sentences), ”… we shall call a definition of truth ‘adequate’ if all these equivalences follow from it.” (although this seems to ignore the fact that there are other important criteria of adequacy) When discussing a particular objection to his view late in the paper, he says, “The author of this objection mistakenly regards scheme (T)… as a definition of truth.” Unfortunately, he also says stuff that might lead one to think he does think of the conjunction of all T-sentences as a definition: “We can only say that every equivalence of the form (T)… may be considered a partial definition of truth, which explains wherein the truth of this one individual sentence consists. The general definition has to be, in a certain sense, a logical conjunction of all these partial definitions.”

I read the “in a certain sense” there as a subtle concession that we will need more than just a conjunction of the T-sentences for an adequate definition of truth. As support for my reading, I appeal to the fact that Tarski explicitly offers a definition of truth in his paper (in section 11), one that is more than just a conjunction of T-sentences. He defines truth in terms of satisfaction, which in turn is defined recursively using rules like: The objects a and b satisfy the sentential function “P(x, y) or Q(x, y)” iff they satisfy at least one of the functions “P(x, y)” or “Q(x, y)”. His definition of truth is basically that a sentence is true iff it is satisfied by all objects and false otherwise. This works because a sentence, unlike a general sentential function, has no free variables to which objects can be bound.

This definition is clearly distinct from the logical conjunction of all T-sentences. Tarski claims it entails all the T-sentences, and therefore satisfies his criterion of adequacy. Now, I think Tarski’s actual definition of truth isn’t all that helpful. He defines truth in terms of satisfaction, but satisfaction is hardly a more perspicuous concept. True, he provides a recursive procedure for determining satisfaction, but this only tells us when compound sentential functions are satisfied once we know when simple ones are satisfied. His account doesn’t explain what it means for a simple sentential function to be satisfied by an object. This is just left as a primitive in the theory. So, yeah, Tarski’s actual theory of truth kind of sucks.

His criterion of adequacy, though, has been very influential. But it is not a theory of truth, and that is not the way it is treated by philosophers. It is used as a test of adequacy, and proponents of most theories of truth (not just the correspondence theory) claim that their theory satisfies this test. So to identify Tarski’s definition/criterion/whatever with the correspondence theory misrepresents the state of play. There are, incidentally, a group of philosophers who do take the T-sentences to be a full definition of truth, or at least to be all that we can say about truth. But these are not correspondence theorists. They are deflationists.

pragmatist 10 Nov 2012 8:35 UTC
45 points
in reply to: gwern’s comment on: Open Thread, November 1-15, 2012
The morally (and socially) appropriate thing to do at this point would be to apologize and pledge not to use that kind of language on IRC in the future, rather than saying “Hey, I don’t do it that often” and subtly digging at startling for publishing your abhorrent comments.

It would also be nice to get an acknowledgement that the things you said aren’t just innocuous expressions of idiosyncratic preferences. They’re examples of the sort of language that has been consistently used to justify and motivate oppression and violence against trans people. Since you recognize that your feelings have no objective justification, your casual transphobia is inexcusable. If you can’t get over those feelings, keep them to yourself please.

pragmatist 18 Dec 2011 7:39 UTC
42 points
in reply to: pragmatist’s comment on: [Link] Belief in religion considered harmful?
Here’s how the discussion between Moldbug and Hanson went:

M: Decision markets won’t work well if P, and we don’t know that ~P.

H: We have data from lab and field experiments, and we always find ~P.

M: Well, induction is useless. Why should I believe ~P for a system you haven’t experimented on?

H: Well, here are some theoretical arguments suggesting ~P.

M: Oh, I don’t deny that often ~P. But how do you know that always ~P?

H: Is there any kind of evidence I could present that would convince you that ~P in the relevant cases?

M: Nope. The problem is, you’re thinking like a social scientist. You need to think like a philosopher.

H: Okay.… so what does thinking like a philosopher reveal?

M: We need a monarch.
What links here?
- torekp's comment on [Link] Belief in religion considered harmful? by [deleted] (18 Dec 2011 18:19 UTC; 5 points)

pragmatist 22 Dec 2014 5:14 UTC
40 points
in reply to: advancedatheist’s comment on: Open thread, Dec. 22 - Dec. 28, 2014

I suspect this describes the wife’s cryopreservation:

I doubt it. The subject of that document was 46 when she died. Chay’s wife was 52, according to news reports.

I suspect the O Administration won’t make a big deal out of it because Chay’s case involves a relatively small amount of money as financial malfeasance goes, and it lacks a racial angle to exploit.

I’m not as opposed to political discussion on this site as many are, but I do think the original point of EY’s “Politics is the Mindkiller” post is worth keeping in mind. Inserting this kind of mind-killing aside in an otherwise non-political comment is needlessly inflammatory and distracting. I don’t want to see this sort of thing on LW.

pragmatist 3 Jul 2014 21:32 UTC
40 points
0
in reply to: Salemicus’s comment on: [moderator action] Eugine_Nier is now banned for mass downvote harassment

Eugine is one of the highest quality posters here and the site will be poorer for his loss. I am not defending his behaviour in this instance but the punishment does not fit the crime.

Many many people have been complaining about mass downvoting for a long time now. A couple of people have also indicated that it has contributed to them not wanting to participate on LW any more. There have been multiple threads with hundreds of comments about this. Eugine is a very frequent visitor to this site, so I’m sure he was aware of all this. Had he stepped in to one of these threads and defended his actions, or apologized for them, or even discontinued the down-voting without admitting to it, I would agree that banning is disproportionate. But he simply ignored the whole discussion and continued surreptitiously block-downvoting people, despite all the disquiet it was causing.

That shows an almost pathological disregard for the well-being of this community and the opinions of its participants. I don’t think banning is an inappropriate response.

That said, I also disagree with your opinion about the general quality of Eugine’s comments, and it is quite probable that this is coloring my judgment in this matter.

Natural Laws Are Descriptions, not Rules

pragmatist8 Aug 2012 4:27 UTC

33 points

237 comments9 min readLW link

pragmatist 19 Apr 2012 9:25 UTC
33 points
on: How can we get more and better LW contrarians?
I disagree with quite a lot of the LW consensus, but I haven’t really expressed my criticisms in the few comments I’ve made. I differ substantially from Sequence line on metaethics, reductionism, materialism, epistemology, and even the concept of truth. My views on these things are similar in many respects to those of Hilary Putnam and even Richard Rorty. Those of you familiar with the work of these gentlemen will know how far off the reservation this places me. For those of you who are not familiar with this stuff, I guess it wouldn’t be stretch to describe me as a postmodernist.

I initially avoided voicing my disagreements because I suspect that my collection of beliefs is not only regarded as false by this community, but also as a fairly reliable indicator of woolly thinking and a lack of technical ability. I didn’t want to get branded right off the bat as someone not worth engaging with. The thought was that I should first establish some degree of credibility within the community by restricting myself to topics where the inferential distance between the average LWer and me is small. I think wannabe contrarians entering into any intellectual community should be encouraged to expend some initial effort on credibility-building by talking about stuff on which they by and large agree with the community. I haven’t been following LessWrong for that long, but I gather that there was a time when Will Newsome’s comments were a lot more.… orthodox. I’m guessing that fact has a lot to do with the way his criticisms are received now.

Another big reason I avoid talking about my disagreements is that they are sufficiently fundamental that I expect a large amount of pushback. I know I find it very hard to disengage from argument, and I suspect that’s also true of a significant proportion of the posters here, so I’m worried that the discussion will be a horrible time suck. I really can’t afford that right now. Perhaps at some time in the future, when I have a little more time, I’ll write a discussion post detailing some of my objections.

pragmatist 2 Sep 2013 6:38 UTC
32 points
in reply to: shminux’s comment on: P/S/A—Sam Harris offering money for a little good philosophy
Hilary Putnam, one of the most prominent living philosophers, is known for publicly changing his mind repeatedly on a number of issues. In the Philosophical Lexicon, which is kind of an inside-joke philosophical dictionary, a “hilary” is defined thus:

A very brief but significant period in the intellectual career of a distinguished philosopher. “Oh, that’s what I thought three or four hilaries ago.”

One issue on which Putnam changed his mind is computational functionalism, a theory of mind he actually came up with in the 60s, which is now probably the most popular account of mental states among cognitive scientists and philosophers. Putnam himself has since disavowed this view. Here is a paper tracking Putnam’s change of mind on this topic, if you’re interested in the details.

The definition of functionalism from that paper:

Computational functionalism is the view that mental states and events – pains, beliefs, desires, thoughts and so forth – are computational states of the brain, and so are defined in terms of “computational parameters plus relations to biologically characterized inputs and outputs” (1988: 7). The nature of the mind is independent of the physical making of the brain: “we could be made of Swiss cheese and it wouldn’t matter” (1975b: 291). What matters is our functional organization: the way in which mental states are causally related to each other, to sensory inputs, and to motor outputs. Stones, trees, carburetors and kidneys do not have minds, not because they are not made out of the right material, but because they do not have the right kind of functional organization. Their functional organization does not appear to be sufficiently complex to render them minds. Yet there could be other thinking creatures, perhaps even made of Swiss cheese, with the appropriate functional organization.

The paper I linked has much more on the structure of Putnam’s functionalism and his reasons for believing it.

The reasons for which Putnam subsequently rejected functionalism are a bit hard to convey briefly to someone without a philosophy background. The basic idea is this: many mental states have content, i.e. they somehow say something about the world outside the mind. Beliefs are representations (or possibly misrepresentations) of aspects of the world, desires are directed at particular states of the world, etc. This “outward-pointing” aspect of certain mental states is called, in philosophical parlance, the intentional aspect of mental states. Putnam essentially repudiated functionalism because he came to believe that the functional aspect of a mental state—it’s role in the computational process being implemented by the brain—does not determine its intentional aspect. And since intentionality is a crucial feature of some mental states, we cannot therefore define a mental state in terms of its functional role.

Putnam’s arguments for the gap between the functional and intentional are again detailed in the paper I linked (section 3). It’s kind of obvious that if we consider a computational process by itself we cannot conclusively determine what role that process is playing in the surrounding ecology—syntax doesn’t determine semantics. Putnam’s initial hope had been that by specifying “biologically characterized inputs and outputs” in addition to the computational structure of the mental process, we include enough information about the relationship to the external world to fix the content of the mental state. But he eventually came up with a thought experiment (the now notorious “Twin Earth” experiment) that (he claimed) showed that two individuals could be implementing the exact same mental computations and have the exact same sensory and motor inputs and outputs, and yet have different mental states (different beliefs, for instance).

Another motivation for Putnam changing his mind is that he claimed to have come up with a proof that every open system can, with appropriate definitions of states, be said to implementing any finite automaton. The gist of the proof is in the linked paper (section 3.2.1). If the conclusion is correct, then functionalism seemingly collapses into vacuity. All open systems, including rocks and carburetors, can be described as having any mental state you’d like. To avoid this conclusion, we need constraints on interpretation—which physical process can be legitimately interpreted as a computational process—but this tells against the substrate-independence that is supposed to be at the core of functionalism.

So that’s one example. Putnam came to believe in functionalism because he thought there were strong arguments for it, both empirical and theoretical, but he subsequently developed counter-arguments that he regarded as strong enough to reject the position despite those initial arguments. Putnam is particularly known for changing his mind on important issues because he has done it so many times, but there are many other prominent philosophers who have had significant changes of mind. Another very prominent example is Ludwig Wittgenstein, who is basically famous for two books, the first of which promulgated a radical view of the relationship between language, the mind and the world (an early form of logical positivism), and the second of which extensively (and, to my mind, quite devastatingly) criticized this view.

pragmatist 3 Jul 2014 23:01 UTC
30 points
in reply to: Salemicus’s comment on: [moderator action] Eugine_Nier is now banned for mass downvote harassment
There is a pretty big difference between ignoring one commenter who doesn’t like you and ignoring the complaints of a large proportion of the community. This wasn’t just one or two people kvetching. It was a large number of people, including many (like me) not directly targeted by the behavior. I don’t think you have any obligation to respond to gwern, but if a significant segment of the community objected strongly to your allegedly trollish behavior, and some valuable contributors said they no longer felt comfortable participating on LW because of that behavior, I would consider it “pathological disregard” for you to continue what you were doing as if none of this was happening, without addressing it in any way.

Keep in mind that Eugine continued (surreptitiously) with his block-downvoting not just after a number of users expressed their dissatisfaction, but also after the administration of this site made it clear they disapproved of the behavior. First Eliezer said that he was trying to track down the block downvoter (he failed for some reason), then Kaj put up this post. And Eugine kept down-voting. I don’t see how this doesn’t read as disregard for the community.

Perhaps he thought he was somehow making the community better by his actions (although it’s much more plausible to me that he was just ridiculously mind-killed, since virtually all of the block-downvoting appears to be motivated by political disagreement), but he was still doing it in the face of the community’s express wishes, and to the evident detriment of community relations. Thinking that his behavior would make the community better/more successful is so disconnected from the reality of what was actually happening that it qualifies as pathological disregard for the community, I think. Disregard for what people think and how they feel, and disregard for the observable consequences of his behavior.

pragmatist 13 Jul 2013 9:02 UTC
30 points
in reply to: drethelin’s comment on: “Stupid” questions thread
An important thing to realize is that people working on anthropics are trying to come up with a precise inferential methodology. They’re not trying to draw conclusions about the state of the world, they’re trying to draw conclusions about how one should draw conclusions about the state of the world. Think of it as akin to Bayesianism. If someone read an introduction to Bayesian epistemology, and said “This is just a mess of tautologies (Bayes’ theorem) and thought experiments (Dutch book arguments) that pays no rent in anticipated experience. Why should I care?”, how would you respond? Presumably you’d tell them that they should care because understanding the Bayesian methodology helps people make sounder inferences about the world, even if it doesn’t predict specific experiences. Understanding anthropics does the same thing (except perhaps not as ubiquitously).

So the point of understanding anthropics is not so much to directly predict experiences but to appreciate how exactly one should update on certain pieces of evidence. It’s like understanding any other selection effect—in order to properly interpret the significance of pieces of evidence you collect, you need to have a proper understanding of the tools you use to collect them. To use Eddington’s much-cited example, if your net can’t catch fish smaller than six inches, then the fact that you haven’t caught any such fish doesn’t tell you anything about the state of the lake you’re fishing. Understanding the limitations of your data-gathering mechanism prevents you from making bad updates. And if the particular limitation you’re considering is the fact that observations can only be made in regimes accessible to observers, then you’re engaged in anthropic reasoning.

Paul Dirac came up with a pretty revisionary cosmological theory based on several apparent “large number coincidences”—important large (and some small) numbers in physics that all seem to be approximate integer powers of the Hubble age of the universe. He argued that it is implausible that we just happen to find ourselves at a time when these simple relationships hold, so they must be law-like. Based on this he concluded that certain physical constants aren’t really constant; they change as the universe ages. R. H. Dicke showed (or purported to show) that at least some of these coincidences can be explained when one realizes that observers can only exist during a certain temporal window in the universe’s existence, and that the timing of this window is related to a number of other physical constants (since it depends on facts about the formation and destruction of stars, etc.). If it’s true that observers can only exist in an environment where these large number relationships hold, then it’s a mistake to update our beliefs about natural laws based on these relationships. So that’s an example of how understanding the anthropic selection effect might save us (and not just us, but also superhumans like Dirac) from bad updates.

So much for anthropics in general, but what about the esoteric particulars—SSA, SIA and all that. Well, here’s the basic thought: Dirac’s initial (non-anthropic) move to his new cosmological theory was motivated by the belief that it is extraordinarily unlikely that the large number coincidences are purely due to chance, that we just happen to be around at a time when they hold. This kind of argument has a venerable history in physics (and other sciences, I’m sure) -- if your theory classifies your observed evidence as highly atypical, that’s a significant strike against the theory. Anthropic reasoning like Dicke’s adds a wrinkle—our theory is allowed to classify evidence as atypical, as long as it is not atypical for observers. In other words, even if the theory says phenomenon X occurs very rarely in our universe, an observation of phenomenon X doesn’t count against it, as long as the theory also says (based on good reason, not ad hoc stipulation) that observers can only exist in those few parts of the universe where phenomenon X occurs. Atypicality is allowed as long as it is correlated with the presence of observers.

But only that much atypicality is allowed. If your theory posits significant atypicality that goes beyond what selection effects can explain, then you’re in trouble. This is the insight that SSA, SIA, etc seek to precisify. They are basically attempts to update the Diracian “no atypicality” strategy to allow for the kind of atypicality that anthropic reasoning explains, but no more atypicality than that. Perhaps they are misguided attempts for various reasons, but the search for a mathematical codification of the “no atypicality” move is important, I think, because the move gets used imprecisely all the time anyway (without explicit evocation, most of the time) and it gets used without regard for important observation selection effects.

pragmatist 16 Aug 2012 11:38 UTC
28 points
in reply to: Viliam_Bur’s comment on: Open Thread, August 16-31, 2012
It is not the fact that the person has black friends that is supposed to count as evidence of their racism. It is the fact that they say that they have black friends in response to an accusation of racism. The response is the evidence, not the fact (if it is a fact) that the response is reporting. So what would be evidence against the racism hypothesis is not saying things like “I’m not racist; some of my best friends are black.”

I’m not saying this is great evidence either, but it is not as obviously ridiculous as thinking that not having black friends is evidence against racism. I wouldn’t be at all surprised if saying “Some of my best friends are black” is anticorrelated with actually having black best friends.

pragmatist 22 Apr 2013 1:39 UTC
27 points
on: Can somebody explain this to me?: The computability of the laws of physics and hypercomputation
There are spacetime models in general relativity (i.e. solutions to the Einstein equations) that permit hypercomputation. In a Malament-Hogarth spacetime, there are wordlines such that an object traveling along the worldline will experience infinite time, but for an observer at some point p outside the wordline, the time it takes for the object to traverse the worldline is finite, and the wordline is entirely within p’s causal past. So if you had a Turing machine traveling along this wordline, it could send a signal to p if and onliy if it halted, and the observer at p is guaranteed to receive the signal if the machine ever halts. No infinite-precision measurements are involved (unless perhaps you believe that a Turing machine operating reliably for an indefinite period of time is tantamount to an infinite-precision measurement).

Are these spacetimes physically possible? Well, like I said, they satisfy the basic laws of GR. However, they are not globally hyperbolic, which means there is is no space-like surface (analogous to an “instant of time”) such that providing all data on that surface fully determines the data over the rest of space-time uniquely. In other words, determinism of a particularly strong variety fails.

The strong version of the cosmic censorship hypothesis essentially states that a physically reasonable spacetime must be globally hyperbolic, so if you take it as a criterion of physical possibility, then Malament-Hogarth spacetimes are not physically possible. I guess this just brings up a certain amount of vagueness in the phrase “physically possible”. It is usually taken to mean “possible according to the physical laws”, but what exactly delimits what counts as a physical law? Suppose our universe is globally hyperbolic. Would it then be a law that space-time is globally hyperbolic? Anyway, if you have a more restrictive notion of physical law, such that only laws of temporal evolution count, then the laws of general relativity at least appear to permit hypercomputation.

At the end of your post you suggest that the computability of physical law might rule out hypercomputation. But the M-H spacetime argument does not require that the laws are uncomputable. There is a simple argument from the computability of the physical laws to the impossibility of hypercomputation if you assume full determinism, but that is an additional assumption. You can easily prove that hypercompuation is physically impossible if you make the following four assumptions (presented in reverse order of plausibility, according to my own metric):

(1) The laws of physics are computable.

(2) The laws of physics are complete (i.e. there are no phenomena that are not covered by the laws).

(3) Spacetime must be globally hyperbolic (i.e. there must be a space-like surface of the kind described above).

(4) Finite-precision data over any space-like surface is sufficient for accurately determining the data everywhere on that surface’s domain of dependence.

pragmatist 21 Oct 2012 21:44 UTC
27 points
in reply to: Eliezer Yudkowsky’s comment on: Causal Reference
The issue is broached by Chalmers himself in The Conscious Mind (p. 201). He says:

… it is sometimes said that reference to an entity requires a causal connection to that entity; this is known as the causal theory of reference. If so, then it would be impossible to refer to causally irrelevant experiences.

He goes on to reject the causal theory of reference.

Here is a relevant excerpt from the SEP article on zombies:

But, arguably, it is a priori true that phenomenal consciousness, whether actual or possible, involves being able to refer to and know about one’s qualia. If that is right, any zombie-friendly account faces a problem. According to the widely accepted causal theory of reference — accepted by many philosophers — reference and knowledge require us to be causally affected by what is known or referred to (Kripke ¹⁹⁷²⁄₈₀); and it seems reasonable to suppose that this too is true a priori if true at all. On that basis, in those epiphenomenalistic worlds whose conceivability seems to follow from the conceivability of zombies — (worlds where qualia are inert) — our counterparts cannot know about or refer to their qualia. That contradicts the assumption that phenomenal consciousness involves being able to refer to qualia, from which it follows that such epiphenomenalistic worlds are not possible after all. Hence zombies are not conceivable in the relevant sense either, since their conceivability leads a priori to a contradiction. To summarize: if zombies are conceivable, so are epiphenomenalistic worlds. But by the causal theory of reference, epiphenomenalistic worlds are not conceivable; therefore zombies are not conceivable.

pragmatist 16 Dec 2011 15:06 UTC
27 points
on: Question about timeless physics
This is a pseudo-problem arising from equivocation about the indexical “I”. You can either use it to refer to yourself as a continuant (an entire space-time worm) or as a momentary object (a temporal part of the space-time worm). Just make sure you’re not mixing the two uses. I think that is what is causing your puzzlement. To dissolve it, let’s focus on the momentary object use of “I”.

Don’t think of your consciousness as somehow moving from step 1 to 2 to 3 and so on. I think it might be better to start out thinking that there are separate objects, separate XiXiDus, at each of these steps. Each one of those momentary-XiXiDu’s is fully conscious. When any one of them says “I”, they are referring to themselves, so “I” in the mouth of each momentary-XiXiDu refers to a different object. Also, when they say “now” they are referring to different times. Thought of that way, there is no mystery when each momentary XiXiDu says “I am here now.” Where else would he (she?) be?

The problem arises because the psychological states of all the momentary-XiXiDu’s are related in a way that makes each one think that he is the only one and that he has been moving through time. So the momentary-XiXiDu at step 3 thinks “I was at 1 and I will be at 7, but I’m now at 3. Why?” Really what’s going on is that XiXiDu-3′s “now” is step 3, just as XiXiDu-1′s “now” is step 1. In some sense XiXiDu-3 is right to say he “was” at step 1, if this is interpreted as him bearing a certain relationship to XiXiDu-1. The mistake is that XiXiDu-3 thinks he is identical to XiXidu-1, and so since he is at step 3, XiXiDu-1 can’t be at step 1. After all, how can a single momentary object be at both step-3 and step-1? Well, it can’t, but this is not a problem, since XiXiDu-3 is not in fact identical to XiXiDu-1.
What links here?
- Tyrrell_McAllister's comment on Question about timeless physics by XiXiDu (16 Dec 2011 16:38 UTC; 5 points)

Why I Reject the Correspondence Theory of Truth

pragmatist24 Mar 2015 11:00 UTC

26 points

30 comments8 min readLW link

pragmatist 6 Jan 2014 21:28 UTC
26 points
in reply to: knb’s comment on: [LINK] Why I’m not on the Rationalist Masterlist

Politics is rarely discussed here to begin with and something like 65*% of LWers are liberals/socialists.

Yes, but people on the far right are disproportionately active in political discussions here, probably because it is one of the very few internet venues where they can air their views to a diverse and intelligent readership without being immediately shouted down as evil. If you actually measured political comments, I suspect you’d find that the explicitly liberal/social ones represent much less than 65%.

pragmatist

Nat­u­ral Laws Are De­scrip­tions, not Rules

Why I Re­ject the Cor­re­spon­dence The­ory of Truth

Natural Laws Are Descriptions, not Rules

Why I Reject the Correspondence Theory of Truth