you would feel justified in regarding the child as being morally distant from you, as distant as a stranger’s child, and so the child’s welfare would not be as important to you as your own. Please correct me if I’m wrong.
That’s right. Also, regarding the child as my own would encourage other people to lie about paternity, which would ultimately reduce welfare by a great deal more. Compare the policy of not negotiating with terrorists: if negotiating frees hostages, but creates more incentives for taking hostages later, it may reduce welfare to negotiate, even if you save the lives of the hostages by doing so.
See, the mother’s deceit has no effect on the moral question (in my moral-consequentialist framework) and it has no effect on my filial love (which is independent of the mother’s fidelity).
Precommitting to this sets you up to be deceived, whereas precommitting to the other position makes it less likely that you’ll be deceived.
That’s right. Also, regarding the child as my own would encourage other people to lie about paternity, which would ultimately reduce welfare by a great deal more. Compare the policy of not negotiating with terrorists: if negotiating frees hostages, but creates more incentives for taking hostages later, it may reduce welfare to negotiate, even if you save the lives of the hostages by doing so.
Precommitting to this sets you up to be deceived, whereas precommitting to the other position makes it less likely that you’ll be deceived.