Argument 3:  Membership in the Species Homo Sapiens

        Let us now turn to the other main reason that people typically offer for thinking that abortion is prima facie seriously wrong.

        This is the idea that it is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens simply because it is a member of homo sapiens.

        That is to say, it is claimed that it is a basic moral principle that it is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens.

    Let us consider, then, the following claim:

It is a basic moral principle that it is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens .

Two Objections to the Species-Based Anti-Abortion Argument

    The claim is open to at least four objections.  We shall consider two:

1.  The Counterexample Objection;

2.  The Objection Involving Possible Non-Human Persons and the Idea of a More General, Underlying Principle.

1.  The Counterexample Objection

        The thrust of the first objection is that the following claim is not even true, let alone a basic moral principle, since there are clear-cut counterexamples to it:

It is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens.

Case 1: Whole Brain Destruction

        Imagine the following situation:

(1) Your whole brain is completely destroyed by a virus, but the rest of your body is unharmed.

(2) Paramedics hook up your body to a life support system that causes your heart to keep beating, and air to be pumped into your lungs.

(3) Nutrients are supplied to your body intravenously.

(4) As a result, all life processes continue in your body, even though your whole brain has been completely destroyed.

Question 1

To what extent would you agree or disagree with the following statement?

“In those circumstances, it would be prima facie seriously wrong for anyone to turn off the life-support system.”

A.  I strongly agree with that statement.

B.  I’m inclined to agree with that statement.

C.  I’m uncertain what to think, or I prefer to pass on this question.

D. I’m inclined to disagree with that statement.

E. I strongly disagree with that statement.

Case 1: Whole Brain Destruction

        Very few philosophers think it is prima facie seriously wrong to turn off the life-support system in such a case.

        If this view is right, then one has a counterexample to both of the following claims:

(1) It is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens.

(2) It is a basic moral principle that it is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens.

Case 2: Complete Destruction of the Upper Brain

        Two relevant facts:

(1) If your upper brain were to be destroyed, you would exhibit no behavior that indicated that you had any psychological capacities, including the capacity for consciousness.

(2) The lower brain, or brain stem, controls respiration and cardiac function.

        So if only your upper brain were destroyed, no life-support system, other than intravenous feeding, would be necessary to keep your body alive.

        Imagine, then, the following situation:

(1) Your upper brain is completely destroyed by a virus, but the rest of your body is unharmed.

(2) Nutrients are supplied to your body intravenously.

(3) As a result, all life processes continue in your body, though the upper brain has been completely destroyed.

Question 2

To what extent would you agree or disagree with the following statement?

“In those circumstances, it would be prima facie seriously wrong for anyone to turn off the intravenous feeding, thereby causing the death of the human organism in question.”

A.  I strongly agree with that statement.

B.  I’m inclined to agree with that statement.

C.  I’m uncertain what to think, or I prefer to pass on this question.

D. I’m inclined to disagree with that statement.

E. I strongly disagree with that statement.

        To sum up the first objection:

(1) Most philosophers hold that when a human’s whole brain has been destroyed, or all of the upper brain, then it is not prima facie seriously wrong to kill the human organism that remains.

(2) If that view is right, then the cases of whole brain destruction and upper brain destruction are counterexamples to the following, crucial claim:

It is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens.

2.  Possible Non-Human Species and the Right to Life

        Let us now turn to the second objection, which can be put as follows.

        Consider the case mentioned before – namely, that of the lovable extraterrestrial, ET.

        Suppose, once again, that rather than being merely an illusion produced by skillful animators, ET was an actual living thing, that he and a number of other members of his species came to earth, and that some of them entered this country.

        What would the moral status of ET and other members of his species be?

Question 3

        To what extent would you agree or disagree with the following statement?

“Even though ET and other adult members of his species would have, by hypothesis, all of the same psychological capacities as humans, it would not be prima facie seriously wrong to kill harmless members of that species.”

A.  I strongly agree with that statement.

B.  I’m inclined to agree with that statement.

C.  I’m uncertain what to think, or I prefer to pass on this question.

D. I’m inclined to disagree with that statement.

E. I strongly disagree with that statement.

        If you think that it would be prima facie seriously wrong to kill harmless members of the ET species, and also any innocent members of the species homo sapiens, then there are two claims that you accept, both concerning cases where killing is seriously wrong:

(1) It is prima facie seriously wrong to kill any innocent member of the ET species.

(2) It is prima facie seriously wrong to kill any innocent member of the biologically defined species homo sapiens.

        So we now have two distinct principles - expressed by (1) and (2) - that people are inclined to accept, both advancing claims about things that it is prima facie seriously wrong to kill.

        The method of searching for principles of greater generality then involves attempting to find some more general principle that explains why these two rather similar principles are true, while some other possible moral principles - such as

(3) It is prima facie seriously wrong to kill carrots.

– are not true.

        But what could the more general principle be that underlies both the claim that it is prima facie seriously wrong to kill any innocent members of our own biological species, homo sapiens, and the claim that it is prima facie seriously wrong to kill any innocent members of the ET biological species, but not prima facie serious wrong to kill carrots?

        Presumably it will have to involve some property that would be common to members of the two species, and which is not shared by, for example, carrots, and which is also a morally relevant property.

        What could such a property be?

        The answer, surely, must involve some sort of reference to the type of mental life that both normal adult members of homo sapiens, and members of the ET species, are capable of.

        Exactly what the underlying principle in question is, is not clear at this point.

        But here are two among a number of possible alternatives:

Alternative 1

It is prima facie seriously wrong to kill any innocent individual that enjoys a mental life that involves the capacity for thought.

Alternative 2

It is prima facie seriously wrong to kill any innocent individual that either enjoys a mental life that involves the capacity for thought, or at least that has the potentiality for doing so.

        In the present context, however, it does not matter which of these two alternatives - or other possibilities - is most plausible.

        The crucial idea at the moment is simply that there must be some more basic principle that specifies some property that suffices to make it the case that it is prima facie seriously wrong to kill anything that has that property, and that could be shared by animals belonging to different species.

        Such a more basic principle will therefore explain why it is prima facie seriously wrong to kill some actual living things, as well as why it would also be prima facie seriously wrong to kill some possible animals – such as ET – if they existed, but why it is not prima facie seriously wrong to kill other living things – such as carrots.

        In order to do that, however, that more basic principle cannot refer to any particular species.

        The conclusion, in short, is that it cannot be a basic moral principle that it is prima facie seriously wrong to kill any members of the biologically defined species homo sapiens.

        There must, instead, be some more general moral principle that does not refer to any particular species, and that provides a criterion for when it is prima facie seriously wrong to kill something that can be applied to any species, actual or possible.

Summing Up

        We have seen that there are at least two reasons why it cannot be a basic moral principle that it is prima facie seriously wrong to kill any member of the biologically defined species homo sapiens.

        First of all, the cases of whole brain destruction and upper brain destruction show that the principle is not even true, let alone a basic moral principle.

        Secondly, it is at least possible for there to be non-human animals that it would be prima facie seriously wrong to kill.

        Consequently, there must be a more general moral principle that does not refer to any particular species, and that provides a criterion for when it would be prima facie seriously wrong to kill something.

        For, otherwise, one would have simply a multitude of unrelated principles, each stating that it was prima facie wrong to kill  different sorts of things, but where none of those principles would offer any explanation for why it was wrong to kill some things, but not other things.