I love this question. The burning research lab scenario… =) Many stem cell research advocates use this objective to justify destroying embryos for medical research. Mk.. lets think.
You are banking that my moral intuitions will drive us to choose the toddler, thus proving I don’t really think the embryo(s) is human after all… Your objection fails for 3 reasons.
First, how does choosing to save one human being over another, or others, prove the one(s) left behind is NOT human? Given a choice between saving my son and a building full of other people, I would save my own kid. Would that prove the others were not human beings?
Second, the debate over embryonic stem cell research is not about choosing whom we’re going to “save”, as in the case of the burning lab. It’s about whom we’re going to deliberately “kill” to benefit us. Saving my own son first is permissible. Shooting those left behind is not, even if it would increase my chances of escape.
Third, moral intuitions are important, but they are not infallible. We must examine them in light of reason. A little over a century ago, many whites thought it unthinkable that anyone would consider black slaves human beings…
My choice doesn’t change the embryos value.