"As one shocked 42-year-old manager exclaimed in the middle of a self-reflective career planning exercise, 'Oh, no! I just realized I let a 20-year-old choose my wife and my career!'"

-- Douglas T. Hall, Protean Careers of the 21st Century

Here's the latest version, what I will attempt to post on the top level when I again have enough karma.

"Life Experience" as a Conversation-Halter

Sometimes in an argument, an older opponent might claim that perhaps as I grow older, my opinions will change, or that I'll come around on the topic. Implicit in this claim is the assumption that age or quantity of experience is a proxy for legitimate authority. In and of itself, such "life experience" is necessary for an informed rational worldview, but it is not sufficient.

The claim that more "life experience" will completely reverse an opinion indicates that to the person making such a claim, belief that opinion is based primarily on an accumulation of anecdotes, perhaps derived from extensive availability bias. It actually is a pretty decent assumption that other people aren't Bayesian, because for the most part, they aren't. Many can confirm this, including Haidt, Kahneman, Tversky.

When an opponent appeals to more "life experience," it's a last resort, and it's a conversation halter. This tactic is used when an opponent is cornered. The claim is nearly an outright acknowledgment of a move to exit the realm of rational debate. Why stick to rational discourse when you can shift to trading anecdotes? It levels the playing field, because anecdotes, while Bayesian evidence, are easily abused, especially for complex moral, social, and political claims. As rhetoric, this is frustratingly effective, but it's logically rude.

Although it might be rude and rhetorically weak, it would be authoritatively appropriate for a Bayesian to be condescending to a non-Bayesian in an argument. Conversely, it can be downright maddening for a non-Bayesian to be condescending to a Bayesian, because the non-Bayesian lacks the epistemological authority to warrant such condescension. E.T. Jaynes wrote in Probability Theory about the arrogance of the uninformed, "The semiliterate on the next bar stool will tell you with absolute, arrogant assurance just how to solve the world's problems; while the scholar who has spent a lifetime studying their causes is not at all sure how to do this."

Hi Morendil,

Thanks for the comment. The particular version you are commenting on was an earlier, worse version than what I posted and then pulled this morning. The version I posted this morning was much better than this. I actually changed the claim about the Sokal affair completely.

Due to what I fear was an information cascade of negative karma, I pulled the post so that I might make revisions.

The criticism concerning both this earlier version and the newer one from this morning still holds though. I too realized after the immediate negative feedback that I actually was combining, poorly, two different points and losing both of them in the process. I think I need to revise this into two different posts, or cut out the point about academia entirely. I will concede that anecdotes are evidence as well in the future version.

Unfortunately I was at exactly 50 karma, and now I'm back down to 20, so it will be a while before I can try again. I'll be working on it.

What you seem to be saying, that I agree with, is that it's irritating as well as irrelevant when people try to pull authority on you, using "age" or "quantity of experience" as a proxy for authority. Yes, argument does screen off authority. But that's no reason to knock "life experience".

If opinions are not based on "personal experience", what can they possibly be based on? Reading a book is a personal experience. Arguing an issue with someone (and changing your mind) is a personal experience. Learning anything is a personal experience, which (unless you're too good at compartmentalizing) colors your other beliefs.

Perhaps the issue is with your thinking that "demolishing someone's argument" is a worthwhile instrumental goal in pursuit of truth. A more fruitful goal is to repair your interlocutor's argument, to acknowledge how their personal experience has led them to having whatever beliefs they have, and expose symmetrically what elements in your own experience lead you to different views.

Anecdotes are evidence, even though they can be weak evidence. They can be strong evidence too. For instance, having read this comment after I read the commenter's original report of his experience as an isolated individual, I'd be more inclined to lend credence to the "stealth blimp" theory. I would have dismissed that theory on the basis of reading the Wikipedia page alone or hearing the anecdote along, but I have a low prior probability for someone on LessWrong arranging to seem as if he looked up news reports after first making a honest disclosure to other people interested in truth-seeking.

It seems inconsistent on your part to start off with a rant about "anecdotes", and then make a strong, absolute claimed based solely on "the Sokal affair" - which at the scale of scientific institutions is anecdotal.

I think you're trying to make two distinct points and getting them mixed up, and as a result not getting either point across. One of these points I believe needs to be moderated - the one where you say "personal experiences aren't evidence" - because they are evidence; the other is where you say "people who speak with too much confidence are more likely to be wrong, including a) people older than you, b) some academics, but not necessarily the academic consensus".

That is perhaps a third point - just why you think that "the process of peer-reviewed scientific inquiry, informed by logic, statistics, and regression analysis, offers a better chance at discovering truth than any other institution in history". That's a strong claim subject to the conjunction fallacy: are each of peer review, logic, statistics and regression analysis necessary elements of what makes scientific inquiry our best chance at discovering truth? Are they sufficient elements to be that best chance?

The issue is not "who gets to read a specific peer reviewed paper" but much more "who benefits from the world state that comes about after the paper existed to be read by anyone".

The obvious benefits are mostly the practical fallout of the research - the technologies, companies, products, medical treatments, social practices, jobs, weapons, strategies, and art forms that occur only by virtue of the research having been done that provided the relevant insights to people who could leverage those insights into various sorts of world improvement. Knowledge dissemination happens via many mechanisms and scientific journals are only an early step in the process.

If the only benefits of science were to individual people who read the papers, then no government on earth should or would subsidize the process. If positive benefits stop being derived from knowledge work, and this fact reaches the public consciousness, democratic subsidy of science will eventually cease.

I reckon it is public good anyway, insofar as public libraries are public. In fact, you can most probably access many of those journals for free at your nearest public library, even if not necessarily by direct web access, but by requesting a copy from the librarian.

EDIT: Of course if you want convenience, you have to pay. (Perhaps) luckily enough people and institutions are willing to.

So, it turns out that power affects what kind of moral reasoning a person uses.

A "public good" is not a Boolean kind of thing. There are degrees of excludability and rivalrousness. Some goods become more or less excludable over time and so may or may not be a public good at any given point. Some scientific knowledge is a public good and some of it isn't, but probably will be in the near future.

Mancur Olson's The Logic of Collective Action might serve as a very useful theoretical tool here, for talking about groups. We might extend Olson's analysis by thinking of how different kinds of groups produce rationality and scientific information.