calef comments on No independence of irrelevant alternatives (picture proof) - Less Wrong

7 Post author: Stuart_Armstrong 03 May 2012 05:48PM

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Comment author: calef 03 May 2012 06:40:51PM 5 points [-]

Why does IIA allow you to rescale the two utility axes using different scaling functions?

Comment author: jsalvatier 03 May 2012 07:00:59PM *  5 points [-]

I think this is a feature of utility functions rather than the IIA assumption; they are unique up to a scaling and offset (positive affine transformation). See this wikipedia article for more. The intuition is that, adding an offset to the whole function, or rescaling it does change the relative comparisons of different points on that function and thus doesn't change the choices for an agent with that utility function.

Comment author: Stuart_Armstrong 03 May 2012 09:05:46PM 4 points [-]

Assumption that there is no canonical scales for the utility functions.