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."
As I've become an old fart, I've found myself using such statements occasionally. And I believe correctly. There ARE topics on which a large amount of difficult-to-communicate experience can make a difference.
To a wannabe bayesean like myself, I'd probably phrase it as:
"This topic is complicated and the evidence that changed my probability estimates over the last few decades is hard to communicate. I find it likely that you will accumulate such evidence as you experience more things, but I don't know how to speed that process up."
Of course, I wouldn't classify such a correspondent as an opponent, just as another truthseeker with a different set of evidence. Also, in many cases, if we agree on some basics, we can profitably disassemble the argument to find subcomponents on which we CAN respect each other enough to find agreement.
I don't mean to say that this isn't rude or annoying, just that sometimes it's correct. Pointing out to someone that they haven't updated (or updated sufficiently) based on your communication of belief is pretty much going to be rude. But so is the fact that you didn't update (sufficiently) when you learned this belief in the first place.
Well, turnabout is fair play. I'm not an old fart, but I've been in a position known for pleading inability to convey their knowledge to the unwashed masses until they they get roughly the same experience. Specifically, that of a graduate student (in control systems), working on a problem at the boundary of current knowledge.
I was very interested in learning what it would be like to get to a state where I literally could not explain the problem I'm working on to people far outside my field (though of course that was not why I went to grad school).
And you... (read more)