One way to paraphrase esp. some of your ice cream example:
Hyperbolic discounting—the habit of valuing this moment a lot while abruptly (not smoothly exponentially) discounting everything coming even just a short while after—may in a technical sense be ‘time inconsistent’, but it’s misguided to call it ‘irrational’ in the common usage of the term: My current self may simply care about itself distinctly more than about the future selves, even if some of these future selves are forthcoming relatively soon. It’s my current self’s preference structure, and preferences are not rational or irrational, basta.
I agree and had been thinking this, and I find it an interesting counterpoint to the usual description of hyperbolic discounting as ‘irrational’.
It is a bit funny also as we have plenty of discussions trying to explain when/why some hyperbolic discounting may actually be “rational” (ex. here, here, here), but I’ve not yet seen any so fundamental (and simple) rejection of the notion of irrationality (though maybe I’ve just missed it so far).
(Then, with their dubious habits of using common terms in subtly misleading ways, fellow economists may rebut that we have simply defined irrationality in this debate as meaning to have non-exponential alias time-inconsistent preferences, justifying the term ‘irrationality’ here quasi by definition)
Taking what you write as excuse to nerd a bit about Hyperbolic Discounting
One way to paraphrase esp. some of your ice cream example:
Hyperbolic discounting—the habit of valuing this moment a lot while abruptly (not smoothly exponentially) discounting everything coming even just a short while after—may in a technical sense be ‘time inconsistent’, but it’s misguided to call it ‘irrational’ in the common usage of the term: My current self may simply care about itself distinctly more than about the future selves, even if some of these future selves are forthcoming relatively soon. It’s my current self’s preference structure, and preferences are not rational or irrational, basta.
I agree and had been thinking this, and I find it an interesting counterpoint to the usual description of hyperbolic discounting as ‘irrational’.
It is a bit funny also as we have plenty of discussions trying to explain when/why some hyperbolic discounting may actually be “rational” (ex. here, here, here), but I’ve not yet seen any so fundamental (and simple) rejection of the notion of irrationality (though maybe I’ve just missed it so far).
(Then, with their dubious habits of using common terms in subtly misleading ways, fellow economists may rebut that we have simply defined irrationality in this debate as meaning to have non-exponential alias time-inconsistent preferences, justifying the term ‘irrationality’ here quasi by definition)