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 the person making such a claim believes that opinions from others are based primarily on accumulating 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, and 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 moving 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."
Prof. Hanson,
I'm 22, and haven't encountered an opportunity where I thought to use this claim. There are probably instances where it would have been factually appropriate for me to do so, but I'm not inclined to make this point, because it seems to me like a cop-out.
Maybe I would have difficulty in explaining something highly technical or specialized to someone with no background, but crying "life experience" doesn't seem to be the proper response. It's far too vague. I would find it more appropriate to direct my debate partner to the specialized or technical material they haven't studied to understand why my position might be different.
The problem is that nebulously appealing to "life experience" doesn't even grant how the debate partner is uninformed. It's as if the person with more "life experience" is on such a higher level of understanding that they can't even communicate how their additional information informs their understanding. Like Silas Barta, I'm skeptical that even the most informed and educated people would ever be simply unable to explain the basic ideas of even the most difficult material. When this claim is not used to try to explain how their training or experience leads them to a different conclusion, I suspect that more often than not, their differing position isn't actually about any specialized training, just that their line of argumentation has run out of steam.
In critiquing postmodernism, Noam Chomsky wrote, "True, there are lots of other things I don't understand: the articles in the current issues of math and physics journals, for example. But there is a difference. In the latter case, I know how to get to understand them, and have done so, in cases of particular interest to me; and I also know that people in these fields can explain the contents to me at my level, so that I can gain what (partial) understanding I may want."
Well most 22 year old are much less likely to have learned so much about something that they find it very hard to explain it to another adult. It isn't usually that one can't point in the direction of the basic idea, it is that your audience doesn't find such general pointing to be very persuasive.