Thanks, I think this is a great post.
Another argument is something like the following:
P1. Consequentialist reasoning is often used to justify the set of actions X.P2. X has bad consequences.C. Therefore, people believing that consequentialism is true has bad consequences.
P1. Consequentialist reasoning is often used to justify the set of actions X.
P2. X has bad consequences.
C. Therefore, people believing that consequentialism is true has bad consequences.
This argument isn’t directly about the truth of consequentialism. But if correct, it would mean that consequentialism is “self-effacing”—that people believing that consequentialism is true has bad consequences. Historically, some have argued that that’s a reason to keep consequentialism, or utilitarianism specifically, secret. There is a debate within moral philosophy about to what extent being self-effacing is a problem for a moral theory.
One could construct an analogous argument concerning longtermism, or maybe specifically consequentialist versions of longtermism.
I’m not necessarily saying that this is what those who give the types of arguments that you cite have in mind, but in any event, it seems to me a type of argument worth being aware of. There’s a large discussion on this topic—not the least in the literature on consequentialism and utilitarianism—that one can draw on.
(I may or may not return to the plausibility of this argument—I don’t have time now.)
If this argument concluded that belief in consequentialism had bad consequences on net, it would be a more serious problem for consequentialism.
Another different and perhaps more relevant question is whether popularizing belief in consequentialism has net bad consequences on the margin.
(Just flagging that this is very related to the discussion in the first part of Reasons and Persons, and for the reasons presented therein I don’t think it’s a decisive argument against consequentialism as criterion of rightness.)
I wrote a more general post on arguments about consequences of misuse of consequentialism and longtermism.