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592 DOHRN
earlier. For although Mary knows that she actually will conceive John, it is not determinately
the case that she would conceive John under the counterfactual supposition.
To develop a second argument, I present a different variation of Hare’s Non-Identity
scenario: just as in Hare’s original scenario, Mary does not know what the omniscient being
knows. At t1, she does not yet know that she will conceive John. Assume the omniscient and
very mighty being unbeknownst to Mary has fixed a condition. There is a law-like connection
between Mary’s conceiving a child earlier and her conceiving John. Under these
circumstances, arguably
if Mary had not acted such as to conceive a child earlier, if Mary had acted such as to
conceive a child earlier, Mary would have conceived John.
The counterfactual criterion yields that Mary ought MR to have conceived a child earlier. But by
Hare’s own lights, judging from reasons within Mary’s purview, she still ought not to have
done so: Mary could not anticipate that she would conceive John. But Mary could anticipate
that conceiving a child later would lead to the child having a better life. Admittedly my second
argument somewhat stretches the boundaries of sound thought experiment. 1 But so does
Hare’s original idea of counterfactually undoing an action.
Daniel Dohrn
Humboldt-Universität zu Berlin
dohrndan@hu-berlin.de
References
Hare, C. 2007: ‘Voices from Another World: Must we Respect the Interests of People Who Do
Not, and Will Never, Exist’, Ethics 117, 3, 498–523.
— 2011: ‘Obligation and Regret When there is No Fact of the Matter About What Would Have
Happened if You Had not Done What You Did’, Noûs 45, 190-206.
Parfit, D. 1989 (originally 1984): Reasons and Persons. Oxford: Oxford University Press.
Velleman, D. 2008: ‘Love and Non-Existence’, Philosophy and Public Affairs 36, 266-288.
1
And there are some uncertainties how law-like conditions of the sort considered behave under
counterfactual suppositions.