Page "Mere addition paradox" Paragraph 10

We can then repeat the argument, and imagine another divide, and ask if it would be better for more extra people to exist, unknown to the people in B, and so on, as before.

We then arrive at a situation C, in which the population is even larger, and less happy, though still with lives worth living.

And if we agree that B is not worse than A, then we would conclude in the same fashion that C is not worse than B.

But then we could repeat that argument again, finally arriving at a situation Z, in which there are an enormous number of people whose lives are worth living, but just barely.

Parfit calls this the Repugnant Conclusion, and says that Z is in fact worse than A, and that it goes against what he believes about overpopulation to say otherwise.

This is a contradiction, but it is not clear how to avoid it.