While all of Cohen’s article is included in the reader, only the third section (72–81) was assigned. The previous sections run through arguments very much like those that Singer made. They’re worth reading, but we won’t discuss them.
Main claim: we are responsible for preventing suffering, but this doesn’t commit us to the strong version of Singer’s principle because we are only responsible for doing our share. If there are still people dying after I have done my share, that’s not my responsibility, it’s the responsibility of those who haven’t done their share. This is illustrated with the example of two communities on an island.
Cohen uses a few terms that might not be familiar. The ideas are, however.
1. ceteris paribus means ‘other things being the same.’ In context, on page 75, what he’s saying is that his argument assumes that those who do their share are in the same moral position as those who don’t: no one has an acceptable excuse for not doing his share, and so on.
2. supererogatory means ‘beyond the call of duty.’ In context, on page 75, what he’s saying is that it might be a good thing if some did more than their fair share but that no one is morally required to do so.
3. Begging the question means ‘giving an argument that simply assumes one’s opponent is wrong rather than proving it.’ In context, on pp 77-8, what he’s saying is that Singer, for example, could claim that Cohen’s orphanage example simply assumes that Singer is wrong. More precisely, Singer could object that Cohen is relying on provoking a reaction to this example — that there is a limit to the number of starving children one must feed short of reducing oneself to starvation levels — that simply assumes all of Singer’s arguments are ineffective. Needless to say, that’s not a persuasive way to refute Singer’s arguments. Be aware that this phrase is often used in common speech to mean "raises a question."