1. Problems of longevity play a central part in mod-
ern debate about the human condition. This concern
stems from the decline since the Renaissance of faith
in supernatural salvation from death; concern with the
worth of individual identity and experience has shifted
from an otherworldly realm to the “here and now,”
with intensification of earthly expectations. One cur-
rent of thought is the belief that the length of life can
be extended significantly by increasing human control
over natural forces, i.e., through biomedical science.
In 1956, Gruman termed this concept “prolongevity.”
Prolongevity is a subsidiary variant of meliorism, the
belief that human effort should be applied to improving
the world. The antonym to meliorism is apologism,
which condemns attempts to alter earthly conditions;
in this essay apologism stands for the idea that pro-
longevity is neither possible nor desirable.
“Length of life” (or longevity) may refer to either
of two different concepts. “Life expectancy” is the
average expectation of life at birth (or at any specified
later age), and, during the course of history, the mean
expectation of life at birth has increased greatly, espe-
cially since 1800. Increased life expectancy reflects
advances in controlling infectious and food-deficiency
diseases, and the rate of increase seems to have reached
a plateau as biomedical science operates in the area
of cardiovascular diseases, cancer, and “aging.”
The other meaning of length of life is “life span,”
the extreme limit of longevity. Statisticians estimate
the maximum human life span at about 110 years; this
has not increased during the course of history. The
concept is valuable in challenging complacent opti-
mism that foresees an automatic increase in longevity
as a by-product of social and scientific progress. But
the concept of life span is not absolute; statisticians
acknowledge numerous assumptions involved in their
analyses (Spiegelman, 1968), and some gerontologists
believe the slope of the Gompertz curve can be
changed (Strehler, 1967).
What constitutes a “significant” extension of lon-
gevity? It is helpful to take into account the scien-
tific and philosophical background of the time. In the
present era, the question focuses on the nature of the
life span: the issue concerns the possibility of some
medical or scientific breakthrough in the field of aging,
and an increase in the healthful and productive period
of life, not merely an extension of time per se.
