Exponential discounting yields time-consistent preferences. Exponential discounting and, more generally, time-consistent preferences are often assumed in rational choice theory, since they imply that all of a decision-maker’s selves will agree with the choices made by each self.
At best, this is an argument not to use non-exponential, translation invariant discounting.
You can discount in a way that depends on time (for example, Robin Hanson would probably recommend discounting by current interest rate, which changes over time; the UDASSA recommends discounting in a way that depends on absolute time) or you can not discount at all. I know of plausible justifications for these approaches to discounting. I know of no such justification for exponential discounting. The wikipedia article does not provide one.
At best, this is an argument not to use non-exponential, translation invariant discounting.
It is an argument not to use non-exponential, discounting.
You can discount in a way that depends on time [...]
Exponential discounting depends on time. It is exponential temporal discounting being discussed. So: values being scaled by ke^-ct—where the t is for “time”.
The prevailing interest rate is normally not much of a factor—since money is only instrumentally valuable.
or you can not discount at all.
That is the trivial kind of exponential discounting, where the exponent is zero.
I know of no such justification for exponential discounting. The wikipedia article does not provide one.
The bit I quoted was a justification. Exponential discounting yields time-consistent preferences. Only exponential discounting does that.
To quote from: http://en.wikipedia.org/wiki/Dynamically_inconsistent
At best, this is an argument not to use non-exponential, translation invariant discounting.
You can discount in a way that depends on time (for example, Robin Hanson would probably recommend discounting by current interest rate, which changes over time; the UDASSA recommends discounting in a way that depends on absolute time) or you can not discount at all. I know of plausible justifications for these approaches to discounting. I know of no such justification for exponential discounting. The wikipedia article does not provide one.
It is an argument not to use non-exponential, discounting.
Exponential discounting depends on time. It is exponential temporal discounting being discussed. So: values being scaled by ke^-ct—where the t is for “time”.
The prevailing interest rate is normally not much of a factor—since money is only instrumentally valuable.
That is the trivial kind of exponential discounting, where the exponent is zero.
The bit I quoted was a justification. Exponential discounting yields time-consistent preferences. Only exponential discounting does that.