Many Weak Arguments and the Typical Mind

post by JonahS (JonahSinick) · 2013-06-06T18:52:32.590Z · LW · GW · Legacy · 9 comments

Contents

   Simplistic generalizations and the typical mind
  The dangers of uncritical generalization 
  Adroit use of simplistic generalizations 
  Comparing the two approaches
  The use of many weak arguments as the default mode of operation for most high functioning people 
  How could we have missed this? 
  Implications
None
9 comments

In my previous post, I advanced the view that discovering and using many weak arguments generally produces better predictive models for answering questions about the human world than discovering and using a single relatively strong argument does.

My impression is that most high functioning people use the “many weak arguments” epistemic framework, and that this contrasts with people like my (past) self. I believe that people like me have misunderstood parts of the reasoning of most high functioning people due to typical mind fallacy, and that by extension, people like me have misunderstood parts of how society works.

I flesh out my thinking on this point below.

 Simplistic generalizations and the typical mind

When we recognize that a member of a reference class has a given feature, we tend to generalize this feature to all members of the reference class. For example, when we encounter an immigrant from a given country, we reflexively assume that other people from the country have the same personality as this immigrant. 

Because most people don’t have the resources or inclination to focus on improving their epistemic rationality, their beliefs are in part derived from uncritical simplistic generalizations of this type.

The reason that this sort of works in practice is that information about one member of a reference class is in fact evidence about other members of the reference class. This is a special case of Bayes’ theorem. But such simplistic generalization often yields bad epistemology, and the functionality of most people’s epistemology is often highly contingent on their use of the beliefs of those around them, which are functional by virtue of having survived natural selection.

The dangers of uncritical generalization 

People responded to the Islamic terrorist attacks on September 11, 2001 by developing xenophobia toward Muslims in general, even though the terrorists represented a tiny fraction of Muslims. The xenophobia toward Muslims that followed the September 11th attacks did a great deal of harm, and if people had not been thinking in such sweeping terms, the harm may have been averted.

With such examples in mind, much of my past effort to improve my epistemic rationality has focused on refining the reflexive simplistic generalizations that I make. I’ve put a great deal of effort into appreciating and understanding the nuances present in a given reference class, and to figure out the appropriate subcategory of a reference class to which to extrapolate a feature of a given member of the reference class.

This style is characteristic of many of my friends. 

Adroit use of simplistic generalizations 

My previous efforts to refine my reflexive simplistic generalizations have largely consisted of working to discover a single relatively strong argument for or against a proposition. As I discussed in my previous post, I now believe using many weak arguments generally yields better predictions about the human world.

Weak arguments often arise from simple generalizations. This is exemplified by the arguments that I gave for majoring in a quantitative subject increasing earnings. The statements “The people who are wealthier majored in quantitative subjects,” “high paying jobs use quantitative skills,” “if you major in a quantitative subject, that shows that you’re smart,” “math teaches you to think,” “people say that majoring in a quantitative subject increases earnings” and “my friends think that majoring in a quantitative subject increases earnings” are each examples of placing something in a reference class that has a substantial probability of being inappropriate.

In my previous post, I used reference classes that have a substantial probability of being inappropriate, in order to derive a confident conclusion. I didn’t do substantive object level investigation of whether or not the reference classes are appropriate. You don’t need to do such an investigation to come to a fairly confident conclusion. All that you need is a sufficiently large number of unrelated reference classes.

In pages 27-28 of Intelligence Explosion Microeconomics, Eliezer wrote

Aside from the Lucas critique, the other major problem I have with the “outside view” is that everyone who uses it seems to come up with a different reference class and a different answer […] I don’t know what to do after two people take different reference classes and come up with different outside views, both of which we ought to just accept. My experience is that people end up doing the equivalent of saying, “I’m taking my reference class and going home.” 

I’m sympathetic to Eliezer’s concerns with the use of the outside view: one can always find a reference class that supports one’s conclusion, and it’s unclear what the “correct” reference class is. Eliezer has argued that the weak inside view is a better alternative. 

There’s not a dichotomy between “the outside view” and “the weak inside view” — one can instead use many independent outside views. This is the “many weak arguments” approach. I believe that this alternative is largely free of the problems with “reference class tennis” that Eliezer highlights, and is generally superior to the use of the weak inside view. 

One can mitigate the problems with using individual simplistic generalizations by using simplistic generalizations from different reference classes and considering the composite picture.

Comparing the two approaches

In epistemology, one observes a member of a given reference class, and wants to determine whether another member of the reference class shares a given feature of the first member. We start our lives by naively extrapolating from the features of the first example to features of the second example. There are two basic ways of improving this aspect of one’s epistemology.

One way is to scrutinize the reference class that the first example falls into, and attempt to alter the reference class until one finds the largest reference class such that all members of the reference class share the feature of the sample member, and see whether the second member of interest falls into this reference class. This is the “one relatively strong argument” approach, and was previously my dominant mode of operation. 

The other way is to attempt to consider many unrelated reference classes that both examples may or may not fit into, keep track of how many reference classes both examples fit into, and use the principle of consilience to assess whether the feature of the first example can reliably be extrapolated to the second example. This is the “many weak arguments” approach. I’ve been striving to make this my dominant mode of operation.

The use of many weak arguments as the default mode of operation for most high functioning people 

I believe that most high functioning people rely primarily on many weak arguments and the principle of consilience. Some reasons that I believe this are:

How could we have missed this? 

If I’m right about all of this, the question arises: Why have people like myself been oblivious to other people’s epistemological framework, and the strengths of this framework relative to our own epistemological framework? The claim that I’m making is a strong one, in light of people like me having previously been unaware of evidence for it. So I think it’s important to address this question. Here I’ll give some hypotheses: 

Implications

The phenomena discussed above have important implications:

Acknowledgements: Thanks to Vipul Naik, Luke Muehlhauser and Nick Beckstead for very helpful comments on an earlier draft of this post. 

Note: I formerly worked as a research analyst at GiveWell. All views expressed here are my own.

 

9 comments

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comment by Qiaochu_Yuan · 2013-06-07T07:41:24.001Z · LW(p) · GW(p)

The reason that this sort of works in practice is that information about one member of a reference class is in fact evidence about other members of the reference class. This is just Bayes’ theorem.

Is it? It's Bayes' theorem together with the assumption that when you see two things that you've put in the same reference class then they're being drawn from the same distribution. Depending on how the reference class is constructed, this may or may not be a reasonable assumption (if it's constructed poorly the distribution may have more salient and unknown parameters than you can reasonably learn). At worst, the reference class might be "everything in the universe," in which case I suppose it's strictly speaking true that information about one thing in the universe is evidence about other things in the universe, but...

Replies from: JonahSinick
comment by JonahS (JonahSinick) · 2013-06-07T15:44:38.065Z · LW(p) · GW(p)

Yes, I wasn't claiming that it's good use of Bayes' theorem. The "sort of" qualification is significant, although I don't think that the use of the "worst case reference class" prevails in practice :-).

Replies from: lukeprog
comment by lukeprog · 2013-06-07T18:27:17.167Z · LW(p) · GW(p)

Yes, I wasn't claiming that it's good use of Bayes' theorem.

I think most readers will read the phrase "This is just Bayes' theorem" as "This is correct use of Bayes' theorem."

Replies from: JonahSinick
comment by JonahS (JonahSinick) · 2013-06-07T18:40:31.498Z · LW(p) · GW(p)

The claim that I intended to make is that "Bayes' theorem implies that the presence of a feature of a member of a given reference class is evidence for the presence of the feature in other members of the reference class." This is technically correct. It's not good epistemology in full generality, for the reason that Qiaochu gives. I'll modify my post to make what I was trying to say more clear.

comment by tondwalkar · 2013-06-11T16:48:16.567Z · LW(p) · GW(p)

With the exception of people on Less Wrong and people in the mathematical community, I’ve almost never seen high functioning people use the “relatively one strong argument” approach.

I think it's more general than that (depending in your definition of the 'mathematical community'). For example, I rarely see physicists attempt to argue something based on many weak arguments, and I think you would find the same to be true of engineers. More generally, I think that anyone who's used to formalism is used to being presented with extremely strong arguments, and ending the search for arguments there. Consider a Bayesian actor who happens to be in a quantitative field of study:

I decide proposition A is true, and sketch out a proof on some scratch paper. The probability that I made a mistake is significantly smaller than the probability that I didn't. I go home and write the proof out formally and carefully, and the probability of me being wrong drops further. I ask a peer to look over it and the probability that I make a mistake is vanishingly small. If prop A is important, then I may publish it, and after peer review, I can say that I have a strong argument for A: I have a proof P, and if P is correct, then so is A, with probability 1. The probability that P is incorrect is small, thanks to the formalism and many levels of peer review.

Since most of the arguments we believe are thus strong arguments, this trains our intuition with a heuristic to not bother looking for arguments that aren't extremely strong. This effect would probably scale with the rigor of the field (eg be much stronger in mathematicians, where proofs are essentially the only form of argument written down)

Replies from: JonahSinick
comment by JonahS (JonahSinick) · 2013-06-11T20:59:21.194Z · LW(p) · GW(p)

The best physicists use the "many weak arguments" approach at least sometimes. See my post on Euler and the Basel Problem for an example of this sort of thing. (Nowadays, physicists fall into the Eulerian tradition more than mathematicians do.)

A close friend who's a general relativity theorist has told me that the best physicists rely primarily on many weak arguments.

Replies from: tondwalkar
comment by tondwalkar · 2013-06-12T16:24:05.044Z · LW(p) · GW(p)

Hmm, I think I may be misunderstanding what you mean by "many weak arguments." As in, I don't think it's uncommon for physicists to make multiple arguments in support of a proposition, but even each of those arguments, IME, are strong enough to bet at least a year of one's career on (eg the old arguments for renormalization), by contrast with, say, continental drift, where you probably wouldn't be taken seriously if you'd produced merely one or two lines of evidence. What this shares with the "one strong argument" position is that we're initially looking for a sufficiently convincing argument, discarding lines of though that would lead to insufficiently strong arguments. It's different mostly in that we go back and find more arguments "to be extra sure," but you're still screening your arguments for sufficient strongness as you make them.

Though admittedly, as a student, I may be biased towards finding my professors' arguments more convincing than they ought to be.

comment by DavidPlumpton · 2013-06-08T01:13:44.754Z · LW(p) · GW(p)

Relying on a small number of strong arguments (or even one) has a clear drawback. Change. A new discovery can invalidate a single argument that seemed very strong in that past. Many weaker arguments have more stability.

Replies from: JonahSinick
comment by JonahS (JonahSinick) · 2013-06-08T01:32:22.603Z · LW(p) · GW(p)

Yes, I discuss this in the "Major weaknesses of the 'single relatively strong argument' approach" section of an earlier post.