A lot of rationalist thinking about ethics and economy assumes we have very well defined utility functions - knowing exactly our preferences between states and events, not only being able to compare them (I prefer X to Y), but assigning precise numbers to every combinations of them (p% chance of X equals q% chance of Y). Because everyone wants more money, you should theoretically even be able to assign exact numerical values to positive outcomes in your life.
I did a small experiment of making a list of things I wanted, and giving them point value. I must say this experiment ended up in a failure - thinking "If I had X, would I take Y instead", and "If I had Y, would I take X instead" very often resulted in a pair of "No"s. Even thinking about multiple Xs/Ys for one Y/X usually led me to deciding they're really incomparable. Outcomes related to similar subject were relatively comparable, those in different areas in life were usually not.
I finally decided on some vague numbers and evaluated the results two months later. My success on some fields was really big, on other fields not at all, and the only thing that was clear was that numbers I assigned were completely wrong.
This leads me to two possible conclusions:
- I don't know how to draw utility functions, but they are a good model of my preferences, and I could learn how to do it.
- Utility functions are really bad match for human preferences, and one of the major premises we accept is wrong.
Anybody else tried assigning numeric values to different outcomes outside very narrow subject matter? Have you succeeded and want to share some pointers? Or failed and want to share some thought on that?
I understand that details of many utility functions will be highly personal, but if you can share your successful ones, that would be great.
I vote for the first possibility - that utility functions are not particularly good match for human preferences, for following reasons: 1) I have never seen one, at least valid outside very narrow subject matter. That implies that people are not good at drawing these functions, which may be caused by the fact that these functions could in reality be very complicated, if even they exist. So even if my preferences are consistent with some utility function, any practical application would apply some strongly simplified model of the function, which could differ significantly from my real preferences. 2) As Roko has said, the utility function is defined rather on histories of universe than on its states. Since my preferences change (and I don't have general desire to keep all of them constant), I am not sure how to treat the time entanglement. 3) From a purely practical point of view, assigning numerical values to very improbable possibilities is prone to numerical errors.
For me some mix of deontology with utilitarianism works better than pure utilitarianism as real-life ethical and decision-making theory.