Can you or anyone expand on "utility of money isn't logarithmic"? It seems a whole bunch of economic theory is based on the wish ("because it has nice propertie

Can you or anyone expand on "utility of money isn't logarithmic"? It seems a whole bunch of economic theory is based on the wish ("because it has nice properties") that losing 10% of your money generally hurts the same amount no matter how much money you have. Even accounting for a non-elastic living wage on the bottom. I know there's a lot of political opinion here, but has there ever been an effort to empirically determine what the utility of money actually is?