Why Utilitarianism is Self-Defeating

I was going to write a long polemic. Then I realised it's best explained this way: utilitarianism seeks to privilege something of greater value over something of less value, despite the intrinsic nature of the things themselves. It has no intrinsic mechanism for determining such value. Therefore, it is an incomplete thing. And an incomplete thing has less value than a complete thing. So utilitarianism cannot be privileged.

The counterargument is: but what if such a mechanism cannot be found? Well, then utilitarianism is worse — it is lunacy. How could you premise a course of thinking or action on something you believe (at least for the purposes of your argument) cannot be found?