How do you measure the intensity of desires, if not by introspectively comparing them (see below)?
You need intensity of desire to compare pains and pleasures, but also to compare pains of different intensities. So if introspection raises a problem for one type of comparison, it should raise a problem for the other type, too. Yet you think we can make comparisons within pains. So whatever reasons you have for thinking that introspection is reliable in making such comparisons, these should also be reasons for thinking that introspection is reliable for making comparisons between pains and pleasures.
Let's assume we make use of memory to rank pains in terms of how much we don't want to undergo them. Likewise, we may rank pleasures in terms of how much we want to have them now (or according to other measurable features). The result is two scales with comparability within the same scale. Now how do you normalize the two scales, is there not an extra source for arbitrariness? People may rank the pains the same way among themselves and the same for all the pleasures too, but when it comes to trading some pain for some pleasure, some people might be very ea...
I've always been more of a theoretician, but it's important to try one's hand at practical problems from time to time. In that vein, I've decided to try three simultaneous experiments on major Less Wrong themes. I will aim to acquire something to protect, I will practice training a seed intelligence, and I will become more familiar with many consequences of evolutionary psychology.
In the spirit of efficiency I'll combine all these experiments into one:
She's never seen Star Wars or Doctor Who.
She's never seen David Attenborough or read J. L. Borges.
She's never had a philosophical debate.
She's never been skiing.
Never had sex, never been hugged or even been licked by a dog!
She has so much to look forwards to...
(Though she'll be very boring for several months yet!)