More lives, better lives

Although many people believe that more people would be better, arguments intended to show this are unconvincing. I consider one of Parfit's arguments for a related conclusion, that even when both are worth living, we ought to prefer the better of two lives. Were this argument successful, or so I claim, then it would follow that more people would be better. But there aren't reasons for preferring the better of two lives. Nor is an attempted rejoinder effective. We can agree that there aren't reasons for preferring the better of two lives, and yet still maintain there are reasons for improving lives.