Suppose that a physicist tells you that black holes lose mass due to something called Hawking radiation, and you have never heard this before. Prior to hearing any explanation of the mechanism or how the conclusion was reached, you should update your probability that black holes lose mass to some form of radiation,
No. What you should do is ask for a justification of the belief. If you do not have the resources available to you to do so, you can fail-over to the trust system and simply accept the physicist's statement unexamined -- but utilization of the trust-system is an admission of failure to have justified beliefs.
You know enough about physicists to know that their beliefs about the mechanics of reality are correlated with fact.
I know enough about physicists, actually, to know that if they cannot relate a mechanism for a given phenomenon and a justification of said phenomenon upon inquiry that I have no reason to accept their assertions as true, as opposed to speculation. If I am to accept a given statement on any level higher than "I trust so" -- that is, if I am to assign a high enough probability to the claim that I would claim myself that it were true -- then I cannot rely upon the trust system but rather must have a justification of belief.
Justification of belief cannot be "A person who usually is right in this field claims this is so" but can be "A person who I have reason to believe would have evidence on this matter related to me his assessment of said evidence."
The difference here is between having a buddy who is a football buff who tells you what the Sportington Sports beat the Homeland Highlanders by last night -- even though you don't know whether he had access to a means of having said information -- as opposed to the friend you know watched the game who tells you the scores.
No. What you should do is ask for a justification of the belief. If you do not have the resources available to you to do so, you can fail-over to the trust system and simply accept the physicist's statement unexamined -- but utilization of the trust-system is an admission of failure to have justified beliefs.
If you want to increase the reliability of your probability estimate, you should ask for a justification. But if you do not increase your probability estimate contingent on the physicist's claim until you receive information on how he established th...
LessWrongers as a group are often accused of talking about rationality without putting it into practice (for an elaborated discussion of this see Self-Improvement or Shiny Distraction: Why Less Wrong is anti-Instrumental Rationality). This behavior is particularly insidious because it is self-reinforcing: it will attract more armchair rationalists to LessWrong who will in turn reinforce the trend in an affective death spiral until LessWrong is a community of utilitarian apologists akin to the internet communities of anorexics who congratulate each other on their weight loss. It will be a community where instead of discussing practical ways to "overcome bias" (the original intent of the sequences) we discuss arcane decision theories, who gets to be in our CEV, and the most rational birthday presents (sound familiar?).
A recent attempt to counter this trend or at least make us feel better about it was a series of discussions on "leveling up": accomplishing a set of practical well-defined goals to increment your rationalist "level". It's hard to see how these goals fit into a long-term plan to achieve anything besides self-improvement for its own sake. Indeed, the article begins by priming us with a renaissance-man inspired quote and stands in stark contrast to articles emphasizing practical altruism such as "efficient charity"
So what's the solution? I don't know. However I can tell you a few things about the solution, whatever it may be:
Whatever you may decide to do, be sure it follows these principles. If none of your plans align with these guidelines then construct a new one, on the spot, immediately. Just do something: every moment you sit hundreds of thousands are dying and billions are suffering. Under your judgement your plan can self-modify in the future to overcome its flaws. Become an optimization process; shut up and calculate.
I declare Crocker's rules on the writing style of this post.