Although fair-minded, Sally Quinn's essay on abortion ("The Lines Blur on Abortion," April 28) perhaps overlooks the distinction between a legally straightforward dividing line for pregnancy termination -- fetal viability -- and a philosophically more meaningful criterion, personhood. By that term, I mean the conscious self-awareness and sense of future that leads to our aspirations, hopes, plans, longings and regrets.
It is these particularly human attributes that make the lives of their possessors precious to them beyond the mere act of living, and which start to emerge only in the third trimester, unlike the earlier arrival of heartbeat and primitive nervous system functions we share with other animals.
Future technology may allow us to support the survival of even very immature fetuses based on these animal properties, but the attributes that make us meaningfully human are an inherent element of our biology that technology can't change.
Coincidentally or not, the current criteria for abortion based on fetal viability serve to restrict this procedure to fetuses at stages before awareness develops. Loss of a fetus at this stage would be a great misfortune for a mother who had hoped to give birth, but perhaps not for a woman who wished to end her pregnancy. The fetus itself would have been incapable of any sense of loss or other regrets, and perhaps this should give solace to those inclined to be troubled by the outcome.