The beginning of life.(Letters)(Letter to the editor)

SIR: On the great questions raised in the recent exchange of letters between God (April 2007) and the Editor (July-August 2007) I have nothing to say, beyond remarking on the difference in tone between the two letters: God comes across as unfailingly urbane, as we would expect of Him, while the Editor, all too often, sounds downright peevish. Whether there is anything we can conclude from this contrast I'm not sure. So I will confine my remarks to one item in the Editor's quarrel, not with God, or even with Peter Coleman, but with another of His amanuenses, Cardinal Pell. It concerns the starting-point of human life. Cardinal Pell thinks it begins at conception. The Editor doesn't. Which of them is right?

It should be easy enough to tell, since, as the Editor says, "this is a scientific question"--and indeed, what other kind of question could it be? The scientific observation of vital signs provides the only possible evidence for the presence of life, in the human species or in any other. The starting-point of life was a scientific question in the Middle Ages too. If, as the Editor notes, St Thomas Aquinas disagreed with Cardinal Pell, and held that human life does not properly begin until halfway through pregnancy, he was relying on what the scientists of his day told him. And thirteenth-century science knew nothing of embryology or cell biology, and had no means of knowing anything.

But if the starting-point of life is a scientific question, why does the Editor cite Peter Singer as an authority in support of his opinion that life begins at some later time? Singer is not a scientist, and his insistence that humanity cannot exist before a nervous system has developed is no more than bald assertion.

The embryo, in any species, begins as a single-cell organism, "smaller than the full stop at the end of this sentence", as its assailants ...