Peter Singer's Love-Hate Relationship with Ideal Theory
Either history matters or it doesn't.
When responding to the libertarian challenges to his duty-to-help argument, Singer says "we need to ask why we should start from the unhistorical, abstract and ultimately inexplicable idea of a human being living independently" (Chapter 8, Practical Ethics). I think this is an odd challenge for Singer to raise to Nozick, Narveson, and the like, as it seems to entail a dismissal of ideal theory: the kind of philosophy theorists like Singer perform.
Later, Singer employs John Rawls's veil of ignorance from A Theory of Justice: "If we imagine ourselves about to begin life as a citizen of either Kuwait or Chad—but we do not know which—would we accept the principle that citizens of Kuwait are under no obligation to assist people living in Chad?" Singer does not answer his own question; to him, this query, like the former, is rhetorical. Yet, in the first quote, Singer seems to regard "unhistorical, abstract" original positions as sophistical; in the second, he employs a thought experiment to deliberately place the reader in an unhistorical and abstract original position (by employing Rawls's the veil of ignorance).
It seems to me that Singer is trying to have his historical cake and eat it too. I don't think he can eat his cake and still possess it.