[ktizo]

Just because a utility function can be defined for a given perspective doesn't mean that it automatically makes sense from within that perspective, given that defining a utility function is choosing to view things from an economic perspective and even in economics there is a difference of opinion of what that actually means, with some economists viewing it as something abstract that is only used to discuss more fundamental things and with others saying that utility functions are in themselves fundamental.

Saying that utility functions are the "what there is to life", is a bit like 42 being the answer to life, the universe and everything in the Hitchhiker's Guide to the Galaxy. What meaning you can draw depends totally on what question you are asking, or what perspective you are looking at it from.

For instance, if you are a squirrel, then an economist might be able to calculate a utility function for your behaviour, however the concept of utility functions themselves have no bearing (as far as we know) on "what there is to life" from the squirrel's perspective.