Essays on Infinite Lifespans
Michael R. Rose
WHAT IS GOING ON?
The evolutionary theory of life-history, aging, etc is not
complete, but it is the best theoretical foundation for under-
standing the phenomena of immortality, old and new. Natural
selection is an amazing thing, but it is not all-powerful. When
natural selection is weak, survival and reproduction should be
imperiled; and natural selection is relatively weak later in life.
Consider genes that kill everyone who has even one copy of
the killer gene. If the gene kills during childhood, it will be
eliminated from the population in a single generation. Under
these circumstances, natural selection is all-powerful and this
is a common intuitive understanding of the action of natural
selection. But if killer genes act during old age, they will not
be resisted by natural selection. The killer genes have already
made it into the next generation. The future survival of the
victim of the killer gene does not matter for the transmission
of the killer genes. Natural selection is too feeble at advanced
At early ages, natural selection is strong, and survival rates
will be high, but not 100 percent, because we do not need
aging to have death. During reproductive adulthood, natural
selection becomes progressively weaker. This increases mortal-
ity rates, and thus causes aging, even under ideal conditions.
These ideas explain both the health of youth and the advance
of aging during adulthood.
But there is a subtle twist that explains eventual immortal-
ity. The force of natural selection steadily falls with adult age.
But it cannot fall forever, because it cannot take on negative
values. As a result, it finally hits zero, and stops falling, near
the end of life. The force of natural selection reaches a plateau
from which it does not budge. This explains why immortality
arises in late life. As natural selection cannot get any worse,
bad evolutionary effects stabilize. Since these bad effects are