mattnewport:
Given your position on the meaninglessness of assigning a numerical probability value to a vague feeling of how likely something is, how would you decide whether you were being offered good odds if offered a bet?
In reality, it is rational to bet only with people over whom you have superior relevant knowledge, or with someone who is suffering from an evident failure of common sense. Otherwise, betting is just gambling (which of course can be worthwhile for fun or signaling value). Look at the stock market: it's pure gambling, unless you have insider knowledge or vastly higher expertise than the average investor.
This is the basic reason why I consider the emphasis on subjective Bayesian probabilities that is so popular here misguided. In technical problems where probability calculations can be helpful, the experts in the field already know how to use them. On the other hand, for the great majority of the relevant beliefs and conclusions you'll form in life, they offer nothing useful beyond what your vague common sense is already telling you. If you start taking them too seriously, it's easy to start fooling yourself that your thinking is more accurate and precise than it really is, and if you start actually betting on them, you'll be just gambling.
If you're not in the habit of accepting bets, how do you think someone who does this for a living (a bookie for example) should go about deciding on what odds to assign to a given bet?
I'm not familiar with the details of this business, but from what I understand, bookmakers work in such a way that they're guaranteed to make a profit no matter what happens. Effectively, they exploit the inconsistencies between different people's estimates of what the favorable odds are. (If there are bookmakers who stake their profit on some particular outcome, then I'm sure that they have insider knowledge if they can stay profitable.) Now of course, the trick is to come up with a book that is both profitable and offers odds that will sell well, but here we get into the fuzzy art of exploiting people's biases for profit.
In reality, it is rational to bet only with people over whom you have superior relevant knowledge, or with someone who is suffering from an evident failure of common sense.
You still have to be able to translate your superior relevant knowledge into odds in order to set the terms of the bet however. Do you not believe that this is an ability that people have varying degrees of aptitude for?
Look at the stock market: it's pure gambling, unless you have insider knowledge or vastly higher expertise than the average investor.
Vastly higher expertise than ...
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Here's an irrationalist game meant to quickly collect a pool of controversial ideas for people to debate and assess. It kinda relies on people being honest and not being nitpickers, but it might be fun.
Write a comment reply to this post describing a belief you think has a reasonable chance of being true relative to the the beliefs of other Less Wrong folk. Jot down a proposition and a rough probability estimate or qualitative description, like 'fairly confident'.
Example (not my true belief): "The U.S. government was directly responsible for financing the September 11th terrorist attacks. Very confident. (~95%)."
If you post a belief, you have to vote on the beliefs of all other comments. Voting works like this: if you basically agree with the comment, vote the comment down. If you basically disagree with the comment, vote the comment up. What 'basically' means here is intuitive; instead of using a precise mathy scoring system, just make a guess. In my view, if their stated probability is 99.9% and your degree of belief is 90%, that merits an upvote: it's a pretty big difference of opinion. If they're at 99.9% and you're at 99.5%, it could go either way. If you're genuinely unsure whether or not you basically agree with them, you can pass on voting (but try not to). Vote up if you think they are either overconfident or underconfident in their belief: any disagreement is valid disagreement.
That's the spirit of the game, but some more qualifications and rules follow.
If the proposition in a comment isn't incredibly precise, use your best interpretation. If you really have to pick nits for whatever reason, say so in a comment reply.
The more upvotes you get, the more irrational Less Wrong perceives your belief to be. Which means that if you have a large amount of Less Wrong karma and can still get lots of upvotes on your crazy beliefs then you will get lots of smart people to take your weird ideas a little more seriously.
Some poor soul is going to come along and post "I believe in God". Don't pick nits and say "Well in a a Tegmark multiverse there is definitely a universe exactly like ours where some sort of god rules over us..." and downvote it. That's cheating. You better upvote the guy. For just this post, get over your desire to upvote rationality. For this game, we reward perceived irrationality.
Try to be precise in your propositions. Saying "I believe in God. 99% sure." isn't informative because we don't quite know which God you're talking about. A deist god? The Christian God? Jewish?
Y'all know this already, but just a reminder: preferences ain't beliefs. Downvote preferences disguised as beliefs. Beliefs that include the word "should" are are almost always imprecise: avoid them.
Additional rules: