Response

Rachels asks whether the Ayalas' choice is morally justifiable. But which choice? They made two. First, they chose to give birth to a child for the purpose of using her bone marrow to save the life of their other daughter. Second, having given birth, they chose to carry out their plan. I interpret Rachels as primarily concerned with the first. His comment "people have always had babies for all sorts of reasons other than the 'ideal' one" suggests a focus upon the justifiability of motivations parents may have in choosing to have children.

Rachels answers the question affirmatively and offers this argument:

(1) The choice made by the parents in hypothetical #1 is morally justifiable.

(2) The choice made by the parents in hypothetical #2 is morally justifiable.

(3) If the choice made by the parents in hypothetical #1 is morally justifiable and the choice made by the parents in hypothetical #2 is morally justifiable then the Ayalas' choice is morally justifiable.

(4) The Ayalas' choice is morally justifiable.

The argument's structure is:

(1) P

(2) Q

(3) (P & Q) --> R

(4) R ¹

Does Rachels intend to argue deductively or nondeductively? He doesn't say. How should he be understood? I take him to be arguing deductively. Philosophers usually argue that way. Of course, sometimes they don't, but when they don't, they typically make the nondeductive status of their argument explicit. Rachels doesn't.

Is his argument deductively valid? It's an instance of Modus Ponens. Hence, the only remaining question is whether his premises are true.

What arguments does Rachels offer for them? None. He does mention that "it would be easy enough to argue" for their truth. Is this a claim of self-evidence? Apparently not, given the use of "argue." Self-evident premises don't need arguments of any kind, even "easy" ones. So, readers are on their own.

Is (1) true? Before answering, readers must answer a prior question. What does it mean? Understanding a proposition's intended content is a necessary condition for ascertaining its truth value. (1) asserts that the choice made in hypothetical #1 is morally justifiable. But what choice? Presumably, a parental choice to have two children rather than one, where that choice is motivated by a reasonable belief that two would probably have lives of normal length but a single child wouldn't, where the parents desire their expected children's intrinsic welfare for its own sake, and, in general, where they conform to any other morally appropriate limitation on parental motivation one cares to mention. Then (1) can be reformulated as "All actions in which parents choose to have two children instead of one, where . . . etc. . . . are morally justifiable actions." Formalize (1) as "All As are Js." (Note that Rachels asks not whether choosing to have a child, simpliciter, is justifiable, but rather whether choosing to have a child on the basis of certain motivations and beliefs is justifiable. It's possible to have children for morally unworthy reasons, even though bringing any child into existence is intrinsically desirable. In making this last point I take seriously a point of view that Rachels makes fun of.) Thus construed, I concede (1)'s truth.

What's the intended meaning of (2)? It asserts that the choice made in hypothetical #2 is morally justifiable. Again, what choice? Presumably, a parental choice to use the bone marrow of an existing child to save the life of another child, where the parents act on the basis of a reasonable belief that no harm will result to the donor child, where they don't regard the donor child purely as a means, but desire its intrinsic welfare, and, in general, where they conform to any other morally appropriate limitation on parental motivations one cares to mention. Then (2) can be reformulated as "All actions in which parents choose to use the bone marrow of an existing child to save the life of...