Abstract
If we distance ourselves from the content of the debate for and against the destruction of human embryos for scientific research purposes, we may be struck by its rhetorical form. Each side thinks not only that it has the superior argument, but that its conclusion is wholly obvious, while the other side’s position is obviously mistaken. Those who defend splitting embryos to obtain stem cells say that it is ridiculous to claim that a tiny zygote or blastocyst without a brain is the same sort of being as we, while those who oppose this research claim it to be clear as day that each of us is the same being we were when newly conceived, though now ..