Jon Kvanvig has a very puzzling objection to interest-relative invariantism (IRI). He claims, I think, that IRI gets the wrong results in cases where there is a lot at stake, but the agent in question gains a lot.
But the objection is puzzling because I can’t even figure out why he thinks IRI has the consequences he says it has. Here’s what I take to be the distinctive claim of IRI.
Consider cases where the following is all true:
- The right thing to do given p is X.
- The right thing to do given Probably p is Y.
- The agent has a lot of evidence for p; sufficient evidence to know p ceteris paribus.
- The agent faces a live choice between X and Y, and the right thing to do in the agent’s situation is Y.
In those cases, we say that the agent doesn’t know p. If they did know p, it would be right to do X. But it isn’t right to do X, so they don’t know p. And this is a form of interest-relativity, since if they were faced with different choices, if in particular the X/Y choice wasn’t live, they may well know p.
As Kvanvig notes, the usual way this is illustrated is with cases where the agent stands to lose a lot if they do X and ¬p is true. But that’s not necessary; here’s a similar case.
S heard on the news that GlaxoSmithKline has developed a new cancer drug that will make billions of dollars in revenue, and that its share price has skyrocketed on the news. Intuitively, S knows that GSK’s share price is very high. Later that day, S is rummaging through his portfolio, and notices that he bought some call options on GSK at prices well below what he heard the current share price is. S is obviously extremely happy, and sets about exercising the options. But as he is in the process of doing this, he recalls that he occasionally gets drug companies confused. He wonders whether he should double check that it is really GSK whose price has skyrocketed, or whether he should just exercise the option now.
Here are the relevant X, Y and p.
X = Exercise the option.
Y = Spend 10 seconds checking a stock ticker to see whether it is worth exercising the option, then do so if it is, and don’t if it isn’t.
p = GSK share price is very high.
Given p, X is better than Y, since it involves 10 seconds less inconvenience. Given Probably p, Y is better than X, since the only downside to Y is the 10 seconds spent checking the stock ticker. The downside of X isn’t great. If S buys shares that aren’t that valuable, he can always sell them again for roughly the same price, and just lose a few hundred dollars in fees. But since any reasonable doubt will make it worth spending 10 seconds to save a risk of losing a few hundred dollars, Y is really better than X.
So, I think, S doesn’t know that p. Once he knows that p, it makes sense to exercise the option. And he’s very close to knowing that p; a quick check of any stock site will do it. But given the fallibility of his memory, and the small cost of double-checking, he doesn’t really know.
So IRI works in cases where the agent stands to gain a lot, and not just where the agent stands to lose a lot. I haven’t seen any cases conforming to the template I listed above where IRI is clearly counter-intuitive. In some cases (perhaps like this one) some people’s intuitions are justly silent. But I don’t think there are any where intuition clearly objects to IRI.
Posted by Brian Weatherson in Uncategorized