Economists talk about utility maximization and profit maximization in the same way that these biologists talk about algae reducing drag coefficients...

Martone, Kost, and Boller (2011) write:

"Intertidal macroalgae must resist extreme hydrodynamic forces imposed by crashing waves. How does frond flexibility mitigate drag, and how does flexibility affect predictions of drag and dislodgement in the field?...  Bladed algae were generally “shape changers”, limiting drag by reducing drag coefficients, whereas the branched alga Calliarthron was an “area reducer”, limiting drag by reducing projected area in flow."

These guys don't actually think that bladed algae reduced drag coefficients. There are lots of equations in the article determining optimal drag coefficients, derived from the laws of fluid dynamics. Nobody is agruing that the algae get together, sketch out the optimal shapes they shift into at a given point on the blackboard given those equations, and then with perfect knowledge, foresight, and technique put it into practice.

But we do think there are good reasons to think the organisms optimize on critical margins. The systems in which they are optimizing may be complicated, but to the extent that we understand the systems they are in we can usually apply a little calculus and pretty quickly come up with this thing called "the optimal point" or "the optimal path" or "the optimal set". We always need to test those calculated optimals against what organisms actually do, of course, but since we've got a good reason (evolution by natural selection) to think organisms grope pretty consistently toward optimality, it's reasonable to calculate the optimality of the system and use it to talk about the behavior of an optimizing organism.

For some reason, people go nuts when mainstream economists do the exact same thing.

Of course human beings don't pull out pen and paper and figure out an optimal choice every time they make a decision. Nobody said they did. But we economists know a lot about the laws governing the social system that human beings operate in. We can bring a little calculus to those laws and quickly get a sense of the sort of behavior that a human being might engage in. We always take that to the data and test and change things where it needs changing. But generally speaking mainstream economics has held up pretty well (that's more or less how you survive as "the mainstream").

Figuring out how human beings approximate optimization - through heuristics, for example - is very important work, just like biologists' attempt to understand the approximation of optimization for animals generally is important work. We award Nobel Prizes for that stuff. We all support that stuff.

But despite the views of some, that is not a reason to dismiss the equally important work of understanding the often very complicated optimization issues involved in human social behavior, in order to develop testable predictions.

Think about the algae and their choice of drag coefficients next time you recycle some tired old criticism of "mainstream economics" and their boorish, naive mathematical models (and maybe try talking to a mainstream economist to see if they actually think the things you are accusing them of thinking, or if instead they're just trying to come up with a workable model of a very complicated system).