An Argument Against Hedonistic Act Utilitarianism

(1) The principles of the Theory of Evolution dictate that a trait is naturally selected for if it increases the likelihood that an organism will survive, either individually or as a species.

(2) Statement (1), when translated into Utilitarian terms, would say: "The principles of the Theory of Evolution dictate that a trait is naturally selected for if it increases or does not decrease utility for an organism, either individually or as a species."

(3) The principles of the Theory of Evolution would support the claim that nocioceptors [a type of pain receptor activated at times of injury or inflammation] are evolutionarily advantageous.
3a: Nocioceptors have been part of human and animal physiology for all of recorded history, indicating that they have not been selected out of most species.

(4) By (3), if nocioceptors are evolutionarily advantageous, their function must be evolutionarily advantageous.

(5) Therefore, the ability to feel pain is evolutionarily advantageous by (3) and (4).

(6) Statement (5), when translated into Utilitarian terms, would say: "Therefore, the ability to feel pain maximizes utility by (3) and (4)."

(7) Hedonistic Act Utilitarianism holds that whatever causes pleasure increases utility, and whatever causes pain decreases utility.

(8) If Hedonistic Act Utilitarianism is true, then the ability to feel pain does not maximize utility.

(9) But the ability to feel pain does maximize utility, by (6).

(10) Therefore, Hedonistic Act Utilitarianism cannot be true [if the Theory of Evolution is correct].