@cshentrup it means you can't talk about utils as a quantity. if we let U=log(c) and c=100, we might as well have said U=100 log(c). you might argue that this is just a change in units, ie Fahrenheit is just an affine transformation of degrees Kelvin. but the substantive point is that you can't compare interpersonally. there is no way i can define U so that 10 utils of Jane's utility is worth the same as 10 utils of Joe's. there's no way to calibrate across people.