Dear Michael P.

In my post, I wasn't referring to Jean Porter's essay specifically or the debate over the destruction of embryos more generally.  I was merely sharing my intuition (formed by experience) that sound reason (on any subject) is often not sufficient to persuade one who has strongly held beliefs or desires.

But, since you mention Jean Porter’s essay…

Robby George and others have set forth with care and precision arguments designed to show the unsoundness of theories of delayed hominization, such as the one evidently endorsed by Professor Porter.  You say that "the fact that someone who has listened carefully to the (reasonable) argument of a Robby George, as Jean Porter has, but still does not find the argument convincing does not mean that she is unreasonable. "  What is your evidence that Professor Porter has "listened carefully" (or listened at all) to Robby's argument, or to the arguments of other eminent philosophers (Finnis, Anscombe, Grisez, Haldane, etc.) who share his basic point of view?  Nothing in the Commonweal article shows that she has.  What is most remarkable about the article is that it does not address the arguments made by Robby and the others I've mentioned at all.  It provides no reasons---let me emphasize the point---no reasons to doubt either the factual and normative premises of these arguments or the inferences to the conclusions Robby and the others draw. 

By contrast to what Professor Porter fails to provide in her article, Robby and the others name the names of their interlocutors and address their arguments directly.  Robby tells his readers what he believes is unsound or inadequate in the scientific or normative premises of the arguments of, say, Peter Singer or Lee Silver or Ronald Dworkin or Michael Gazzaniga or Michael Sandel, or what he believes is unwarranted or logically fallacious in inferences they draw from those premises.  Readers can judge for themselves who has the stronger case.  But readers of Professor Porter's article are provided with nothing even remotely equivalent.  Appealing to Professor Porter's authority is simply not good enough.  She may very well be as eminent as you say she is.  But we'll know whether there is anything unsound or "unreasonable" in her defense of delayed hominization only when she tells us her reasons for believing it and provides reasons for rejecting the arguments against it that have been advanced by people at least as eminent as she is---arguments that appear to be decisive by virtue of the apparent soundness of their premises and warrantedness of their inferences. 

Perhaps you know of writings in which Professor Porter addresses the analytically rigorous case presented by philosophers who defend the proposition that human life in all stages and conditions possesses profound, inherent, and equal dignity.  If so, I would be grateful if you would tell us where precisely she identifies a factual or logical error in their argument about the status of human life in the embryonic stage.  Her Commonweal argument does not do that.  In fact, it does not address (even implicitly, much less by specific reference) the arguments advanced by those (including, most recently, John Finnis) who deny her assertion that Aquinas's belief in delayed hominization did not depend on faulty premises drawn from what no one denies was his misunderstanding of the facts of human embryogenesis and early intrauterine human development.   My understanding is that Professor Porter's main field is the interpretation of Aquinas.  In this area, at least, she should provide arguments and address the counterarguments advanced by critics of her views. 

In short, I do not claim that Professor Porter is unreasonable; but neither do I accept the soundness or even reasonableness of her rejection of careful or precise argumentation against her positions on the basis of her professorial standing or prestige.  Those of us who want to know whether her rejection is warranted will need to be given her reasons.

Pax,

Michael S.