However, scientists seem to be all too willing to ignore the scientific definition and to instead substitute it with one that is completely non-scientific. There are multiple examples of this, but this one by neurobiologist and member of the President's Council on Bioethics Michael Gazzaniga is very illustrative of this. This is from a letter to the journal Science shortly after Hwang first published (later retracted) his paper on human cloning.
Many people recognize that the human embryo, the entity that is created by the union of an egg and sperm, carries all the genetic information of a member of the human species. Thus, they call the embryo a human being. Of course, to develop into a human being, the embryo has to become implanted into the uterus of a woman and be allowed to develop. This potential to become a human being is what sticks in the minds of the supporters of the moral equivalence argument and this is why manipulations of embryos for anything but normal reproduction is not acceptable to them.
Looking at a minuscule ball of cells in a Petri dish, so small that it could rest on the head of a pin finds one hard pressed to think of it as a human being. After all, it has no brain or capacity to think and feel. The ball of cells has the potential if it was to be implanted into a woman but so do the egg and sperm ‘set’ before they meet. Why don’t we revere those entities? Well, it is argued, because they don’t have the full compliment of genetic material that could make up a human being. Those that see a bright line here, the line between an entity with the combined genetic material versus the uncombined entities, are forgetting the central discoveries of neuroscience and developmental psychology.
I could blog for a week on this. However, I wish to attempt to stick to the point. Gazzaniga does not accept that being an organism of our species is a sufficient condition for membership in the family of "human beings". In fact, he asserts at least four different conditions that are also necessary to be a human being. To be a "human being to Gazziniga" (HBG), a human organism must also:
1) Be in an environment where it can continue to develop
2) Be of a certain size and
3) Have a certain minimum amount of neural structures in place, which allow the capacity to "think" and "feel"
4) Look like something other than a "ball of cells".
At first, my tendency is to refute his assertions with the philosophical arguments that Scott has mentored me through. However, that misses the point here. Gazziniga is attempting to modify the scientific definition of a human being with one that has no basis in science. How are we to test whether or not a human being is a HBG based on where it currently resides? What is the scientifically testable number of cells that a human organism needs to be considered a HBG? Can that number be challenged and falsified by new evidence? How many neural structures, and what empirical evidence reveals that a human organism has reached HBG status? Not one of these assertions hold up to the scrutiny of science.
Gazziniga would have us believe that there are two subsets of human organisms. One set (the HBG) have acquired or shortly will acquire (which is another issue with his assertions) the accidental qualities that make it morally relevant, and the other set lacks some set of accidental qualities which means they don't count. This is not science. This is his ideology and philosophy regarding the moral value of human beings.
Lastly, how are we to test whether or not a certain human organism qualifies to be a HBG, and thus worthy of moral standing? We can't use science, because moral standing can't be seen in a microscope or separated in a test tube. It seems that Gazziniga would simply need to tell us himself. And we would be required to accept his answer, by faith.