In a letter in last week’s Science John T. Durkin provides a Stalwart’s defense to a Dealer’s argument made by Michael S. Gazzaniga in an earlier letter to Science.

This exchange shows that this debate cannot be settled on scientific grounds and why the issue of stem cells is both highly political and closely related to the abortion debate.

Durkin: “The scientist who destroys an embryo to harvest stem cells commits a wrong, for the scientist has denied that embryo the opportunity to grow into an adult. My moral objections to human embryonic stem cell research are not assuaged by severing its connection to reproductive cloning. In my judgment, the developmental events leading from fertilized ovum, to blastula, to embryo, to fetus, to fully formed adult constitute a continuum. It is artificial, and even self-serving, to declare the embryo “not yet human” before some point, and to declare that we may do with that embryo as we will.”

Gazzaninga: “Looking at a miniscule ball of cells in a petri dish, so small that it could rest on the head of a pin, one may be hard pressed to think of it as a human being. After all, it has no brain or capacity to think and feel. Merely possessing the genetic material for a future human being does not make a ball of cells a human being. The developing embryo that becomes a fetus that becomes a baby is the product of a dynamic interaction with its in vivo environment, its postnatal experiences, and a host of other factors. A pure genetic description of the human species does not describe a human being.”

I discuss these sorts of debates which may be related to science but cannot be addressed by science in this paper:

Pielke, Jr., R. A. 2004. Abortion, Tornadoes and Forests: Thinking about Science, Politics and Policy, Chapter 9, pp. 143-52 in J. Bowersox and K. Arabas (eds.) Forest Futures: Science, Policy and Politics for the Next Century (Rowman and Littlefield).

A pre-publication version here and the published version will be online soon.