Essays on Infinite Lifespans
Michael R. Rose
aquatic animal that used to be a staple of high school biol-
ogy. Martinez found that his Hydra showed no substantial
fall in survival rates over very long periods. They still died, but
not in a pattern that suggested aging. Other scientists have
gathered comparable data with small animals. [e.g. 3] Some
species were immortal and some were not. The immortal spe-
cies reproduced without sex.
Also, invoking laws of thermodynamics as limits to life is
clearly incorrect, given the evolutionary immortality of life
forms. Such an invocation was always rankly amateur in any
case, since these laws only apply to closed systems. Life on
Earth is not a closed system. The earth receives an abundant
input of energy from the sun.
Thus, some of the deepest prejudices of professional biolo-
gists concerning immortality are certainly false. Aging is not
universal. There are organisms that are biologically immortal.
However, this is not a very substantial conclusion. We knew
enough about the biology of death decades ago to come to
this finding. In a sense, what I have just described is the old
immortality, the immortality that has always been with us.
Below, I will describe a new immortality that has come into
view only in the last decade or so.
RECENT RESEARCH ON THE DEMOGRAPHY OF
Another superstition of most biologists is that, once aging
starts, it continues implacably until every organism is dead.
But is aging implacable?
In terms of mortality rates, we can re-state this question as
whether or not aging species are subject to continually increas-
ing mortality rates throughout adulthood. A deceleration
in mortality was found first in human data. [4;5] Very old