Science fiction writer Patrick Tomlinson recently proffered what he took to be a drop-the-mic thought experiment, revealing that while pro-lifers say “life begins at conception” they don’t really believe this is true.

His argument begins as follows:

Here’s the basic idea:

  1. If pro-lifers really believed that life begins at conception, then forced to choose in the event of a fire at a fertility clinic, they would logically save one thousand embryos over one 5-year-old child.
  2. In reality, most pro-lifers would choose to save the one 5-year-old child.
  3. Therefore, pro-lifers do not really believe that an embryo and a human life are of equal value, thus revealing that they do not truly believe that life begins at conception.

A few years ago, Robert P. George (McCormick Professor of Jurisprudence at Princeton University) and Christopher O. Tollefsen (College of Arts and Sciences Distinguished Professor of Philosophy at the University of South Carolina) co-authored a clear and powerful work of moral and scientific reasoning entitled Embryo: A Defense of Human Life.

The book includes a response to this common argument, and they have adapted and updated the response in a new post at The Public Discourse.

If Mr. Tomlinson’s tweetstorm is the sort of thing you would have trouble answering, or if you find it difficult to spot the incorrect logical inferences, then you will find their piece helpful.

Here is the conclusion:

In consequence, we think it entirely unreasonable to infer, as Mr. Tomlinson does, from the choice to save the five-year-old girl, that “No one believes life begins at conception. No one believes embryos are babies, or children. Those who claim to are trying to manipulate you so they can control women.”

As we have noted, it is the standard teaching of every developmental biology textbook we have found that not simply life, but the life of a human being begins at conception. And, while embryos are not “babies,” they are, as a matter of sheer biological fact, living members of the species homo sapiens—human beings in the earliest stage of their natural development.

Unless denied or deprived of a suitable environment, or killed by violence or disease, they will develop by an internally directed process from the embryonic stage into the fetal infant child, and adolescent stages, and into adulthood with their determinateness, unity, and identity fully intact.

That is what each of us did who is now an adult. Each of us is the same person—the same living member of the human species—who earlier in his or her life was an adolescent, a child, a toddler, a newborn infant, a fetus, and, at the very beginning, a newly conceived embryo.

By contrast, none of us was ever an ovum or a spermatozoon. Those were (both functionally and genetically) parts of other persons, namely, our parents, whose uniting brought us into being precisely as embryonic human beings.

No plausible reason has been given, we think, why some living human beings should be treated as deserving full moral respect and immunity from intentional killing, while other living human beings, differing from the first only in size, developmental stage, and location, should be treated as not deserving such respect.

The pro-life view is thus deeply motivated by the principle of the fundamental equality in dignity of all human beings, and certainly not by a desire to manipulate and control. And that conviction is founded on undeniable biological facts, and on a firm commitment to the principle of the equal dignity of each and every member of the human family.