Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

"Outside View!" as Conversation-Halter

50 Eliezer_Yudkowsky 24 February 2010 05:53AM

Followup toThe Outside View's Domain, Conversation Halters
Reply toReference class of the unclassreferenceable

In "conversation halters", I pointed out a number of arguments which are particularly pernicious, not just because of their inherent flaws, but because they attempt to chop off further debate - an "argument stops here!" traffic sign, with some implicit penalty (at least in the mind of the speaker) for trying to continue further.

This is not the right traffic signal to send, unless the state of knowledge is such as to make an actual halt a good idea.  Maybe if you've got a replicable, replicated series of experiments that squarely target the issue and settle it with strong significance and large effect sizes (or great power and null effects), you could say, "Now we know."  Or if the other is blatantly privileging the hypothesis - starting with something improbable, and offering no positive evidence to believe it - then it may be time to throw up hands and walk away.  (Privileging the hypothesis is the state people tend to be driven to, when they start with a bad idea and then witness the defeat of all the positive arguments they thought they had.)  Or you could simply run out of time, but then you just say, "I'm out of time", not "here the gathering of arguments should end."

But there's also another justification for ending argument-gathering that has recently seen some advocacy on Less Wrong.

An experimental group of subjects were asked to describe highly specific plans for their Christmas shopping:  Where, when, and how.  On average, this group expected to finish shopping more than a week before Christmas.  Another group was simply asked when they expected to finish their Christmas shopping, with an average response of 4 days.  Both groups finished an average of 3 days before Christmas.  Similarly, Japanese students who expected to finish their essays 10 days before deadline, actually finished 1 day before deadline; and when asked when they had previously completed similar tasks, replied, "1 day before deadline."  (See this post.)

Those and similar experiments seem to show us a class of cases where you can do better by asking a certain specific question and then halting:  Namely, the students could have produced better estimates by asking themselves "When did I finish last time?" and then ceasing to consider further arguments, without trying to take into account the specifics of where, when, and how they expected to do better than last time.

From this we learn, allegedly, that "the 'outside view' is better than the 'inside view'"; from which it follows that when you're faced with a difficult problem, you should find a reference class of similar cases, use that as your estimate, and deliberately not take into account any arguments about specifics.  But this generalization, I fear, is somewhat more questionable...

continue reading »

Conversation Halters

38 Eliezer_Yudkowsky 20 February 2010 03:00PM

Related toLogical Rudeness, Semantic Stopsigns

While working on my book, I found in passing that I'd developed a list of what I started out calling "stonewalls", but have since decided to refer to as "conversation halters".  These tactics of argument are distinguished by their being attempts to cut off the flow of debate - which is rarely the wisest way to think, and should certainly rate an alarm bell.

Here's my assembled list, on which I shall expand shortly:

  • Appeal to permanent unknowability;
  • Appeal to humility;
  • Appeal to egalitarianism;
  • Appeal to common guilt;
  • Appeal to inner privacy;
  • Appeal to personal freedom;
  • Appeal to arbitrariness;
  • Appeal to inescapable assumptions.
  • Appeal to unquestionable authority;
  • Appeal to absolute certainty.

Now all of these might seem like dodgy moves, some dodgier than others.  But they become dodgier still when you take a step back, feel the flow of debate, observe the cognitive traffic signals, and view these as attempts to cut off the flow of further debate.

continue reading »

Demands for Particular Proof: Appendices

26 Eliezer_Yudkowsky 15 February 2010 07:58AM

Appendices toYou're Entitled to Arguments, But Not (That Particular) Proof

(The main article was getting long, so I decided to move the appendices to a separate article which wouldn't be promoted, thus minimizing the size of the article landing in a promoted-article-only-reader's feed.)

A.  The absence of unobtainable proof is not even weak evidence of absence.

The wise will already know that absence of evidence actually is evidence of absence; and they may ask, "Since a time-lapse video record of apes evolving into humans would, in fact, be strong evidence in favor of the theory of evolution, is it not mandated by the laws of probability theory that the absence of this videotape constitute some degree of evidence against the theory of evolution?"

(Before you reject that proposition out of hand for containing the substring "evidence against the theory of evolution", bear in mind that grownups understand that evidence accumulates.  You don't get to pick out just one piece of evidence and ignore all the rest; true hypotheses can easily generate a minority of weak pieces of evidence against themselves; conceding one point of evidence does not mean conceding the debate; and people who try to act as if it does are nitwits.  Also there are probably no creationists reading this blog.)

The laws of probability theory do mandate that if P(H|E) > P(H), then P(H|~E) < P(H).  So - even if absence of proof is by no means proof of absence, and even if we reject the philosophy that absence of a particular proof means you get to discard all the other arguments about evidence and priors - must we not at least concede that absence of proof is necessarily evidence of absence, even though it may be very weak evidence?

continue reading »

You're Entitled to Arguments, But Not (That Particular) Proof

57 Eliezer_Yudkowsky 15 February 2010 07:58AM

Followup toLogical Rudeness

"Modern man is so committed to empirical knowledge, that he sets the standard for evidence higher than either side in his disputes can attain, thus suffering his disputes to be settled by philosophical arguments as to which party must be crushed under the burden of proof."
        -- Alan Crowe

There's a story - in accordance with Poe's Law, I have no idea whether it's a joke or it actually happened - about a creationist who was trying to claim a "gap" in the fossil record, two species without an intermediate fossil having been discovered.  When an intermediate species was discovered, the creationist responded, "Aha!  Now there are two gaps."

Since I'm not a professional evolutionary biologist, I couldn't begin to rattle off all the ways that we know evolution is true; true facts tend to leave traces of themselves behind, and evolution is the hugest fact in all of biology.  My specialty is the cognitive sciences, so I can tell you of my own knowledge that the human brain looks just like we'd expect it to look if it had evolved, and not at all like you'd think it would look if it'd been intelligently designed.  And I'm not really going to say much more on that subject.  As I once said to someone who questioned whether humans were really related to apes:  "That question might have made sense when Darwin first came up with the hypothesis, but this is the twenty-first century.  We can read the genes.  Human beings and chimpanzees have 95% shared genetic material.  It's over."

Well, it's over, unless you're crazy like a human (ironically, more evidence that the human brain was fashioned by a sloppy and alien god).  If you're crazy like a human, you will engage in motivated cognition; and instead of focusing on the unthinkably huge heaps of evidence in favor of evolution, the innumerable signs by which the fact of evolution has left its heavy footprints on all of reality, the uncounted observations that discriminate between the world we'd expect to see if intelligent design ruled and the world we'd expect to see if evolution were true...

...instead you search your mind, and you pick out one form of proof that you think evolutionary biologists can't provide; and you demand, you insist upon that one form of proof; and when it is not provided, you take that as a refutation.

You say, "Have you ever seen an ape species evolving into a human species?"  You insist on videotapes - on that particular proof.

And that particular proof is one we couldn't possibly be expected to have on hand; it's a form of evidence we couldn't possibly be expected to be able to provide, even given that evolution is true.

Yet it follows illogically that if a video tape would provide definite proof, then, likewise, the absence of a videotape must constitute definite disproof.  Or perhaps just render all other arguments void and turn the issue into a mere matter of personal opinion, with no one's opinion being better than anyone else's.

continue reading »

False Majorities

35 JamesAndrix 03 February 2010 06:43PM

If a majority of experts agree on an issue, a rationalist should be prepared to defer to their judgment. It is reasonable to expect that the experts have superior knowledge and have considered many more arguments than a lay person would be able to. However, if experts are split into camps that reject each other's arguments, then it is rational to take their expert rejections into account. This is the case even among experts that support the same conclusion.

If 2/3's of experts support proposition G , 1/3 because of reason A while rejecting B, and 1/3 because of reason B while rejecting A, and the remaining 1/3 reject both A and B; then the majority Reject A, and the majority Reject B. G should not be treated as a reasonable majority view.

This should be clear if A is the koran and B is the bible.

continue reading »

Logical Rudeness

65 Eliezer_Yudkowsky 29 January 2010 06:48AM

The concept of "logical rudeness" (which I'm pretty sure I first found here, HT) is one that I should write more about, one of these days.  One develops a sense of the flow of discourse, the give and take of argument.  It's possible to do things that completely derail that flow of discourse without shouting or swearing.  These may not be considered offenses against politeness, as our so-called "civilization" defines that term.  But they are offenses against the cooperative exchange of arguments, or even the rules of engagement with the loyal opposition.  They are logically rude.

Suppose, for example, that you're defending X by appealing to Y, and when I seem to be making headway on arguing against Y, you suddenly switch (without having made any concessions) to arguing that it doesn't matter if ~Y because Z still supports X; and when I seem to be making headway on arguing against Z, you suddenly switch to saying that it doesn't matter if ~Z because Y still supports X.  This is an example from an actual conversation, with X = "It's okay for me to claim that I'm going to build AGI in five years yet not put any effort into Friendly AI", Y = "All AIs are automatically ethical", and Z = "Friendly AI is clearly too hard since SIAI hasn't solved it yet".

Even if you never scream or shout, this kind of behavior is rather frustrating for the one who has to talk to you.  If we are ever to perform the nigh-impossible task of actually updating on the evidence, we ought to acknowledge when we take a hit; the loyal opposition has earned that much from us, surely, even if we haven't yet conceded.  If the one is reluctant to take a single hit, let them further defend the point.  Swapping in a new argument?  That's frustrating.  Swapping back and forth?  That's downright logically rude, even if you never raise your voice or interrupt.

The key metaphor is flow.  Consider the notion of "semantic stopsigns", words that halt thought.  A stop sign is something that happens within the flow of traffic.  Swapping back and forth between arguments might seem merely frustrating, or rude, if you take the arguments at face value - if you stay on the object level.  If you jump back a level of abstraction and try to sense the flow of traffic, and imagine what sort of traffic signal this corresponds to... well, you wouldn't want to run into a traffic signal like that.

continue reading »