Transcript Ageing and Human Nature

Ageing - a human necessity?
A cultural constructionist approach to
Anti-ageing science
14.00-14.30
John Vincent (Sociology):
Cosmetic:
Stem cell research to prevent greying hair
Laboratory for Stem Cell Biology, Center for Developmental Biology,
RIKEN
Shin-Ichi Nishikawa, M.D., Ph.D.
Professor
“Medical”
A4M: Hormone therapy to slow ageing.
Drs Klatz and Goldman
Biological
Valter Longo, University of Southern California
• “Longo’s group put baker’s yeast
on a calorie-restricted diet and
knocked out two genes, RAS2
and SCH9, that promote aging in
yeast and cancer in humans.
• “We got a 10-fold life span
extension that is, I think, the
longest one that has ever been
achieved in any organism,”
Longo”
http://biosingularity.wordpress.co
m/2008/01/11/10-fold-life-spanextension-reported-in-simpleorganism/
Immortalist
Aubrey de Grey
Strategies for Engineered Negligble Senescence
• “The cure of aging must now be taken
seriously by responsible
gerontologists, because it is no longer
science fiction. It is patently not yet
science fact either, but it has crossed
the boundary into science
foreseeable. Its elevation to science
fact is a foregone conclusion,” (de
Grey 2003: 934)
“if men define situations as real, they are real in
their consequences” (Thomas and Thomas 1928: 572)
• It is people’s belief in the
inevitable progress of science
that makes them arrange for
their bodies to be frozen with
the intention of being restored
to life when science has made
sufficient progress.
• Further, their understanding of
body and self, as derived from
Enlightenment thought, leads
them to think it is they, some
personalized self-conscious
identity, which will be
resurrected.
Two questions: can it be done? should it be
done?
• It can’t be done at the moment, but much debate
about how soon it might be done. Few doubt that
on day scientific knowledge will create the
potential for greatly extended longevity.
• A great deal of discussion of the ethics of
extended longevity
• Christine Overall (2003) Aging, Death, and
Human Longevity: A Philosophical Inquiry
contrasts prolongivist v. apologist points of view
‘Apologist’ arguments
against the prolongation of human life span
1) Why death should not be dreaded
2) Why death is a natural part of the
‘rhythm of life’.
3) Why the human life span is long
enough
4) Why the social cost of prolonging
human life is too high.
‘Prolongivist’ arguments in favour of
extended life.
1) The intrinsic value of longevity – gain experience,
knowledge, wisdom (?) with increased life.
2) The intrinsic value of life – all life is good so the more the
better. [this is the one that convinces Overall most.]
3) The right to life – ones share of life doesn’t get used up
or run out. Inequalities of life expectancy are unfair.
4) Advances in health care and other contributions to
human well-being – life can only get better [cannot stop
science, gain from increased knowledge and experience
of those who have already acquired knowledge]
Other key issues
• Resource limits of the planet
• Loss of all one knows
• The problem of boredom - “millions long for immortality
who don’t know what to do with themselves on a rainy
Sunday afternoon.”
• Chronological age and its physical limitations [what age
do you want to be immortal at?] shades into human
enhancement and post-humanism.
Evolutionary theories of ageing
• Antagonistic peleiotrapy. [Medewar, Williams]
• “In 1952, Peter Medawar concluded that the accumulation of these
late-acting deleterious genetic variants over time would lead to the
evolution of aging (3).
• Building on Medawar’s “mutation accumulation” theory, Williams
suggested that selection might actually favor deleterious mutations if
they have beneficial pleiotropic effects early in life, when the force of
selection is strong. Aging and its attendant symptoms, including
cardiovascular disease, cancer, and diabetes, might thus be a
maladaptive by-product of selection for genetic variants that aid
development, reproduction, and survival during youth.” (Thomas
Flatt and Daniel E. L. Promislow (2007) Still Pondering an Age-Old
Question. 23 November 2007 Vol 318:1256 Science
www.sciencemag.org)
Disposable soma.
Tom Kirkwood
• Mathematical modelling the trade-off between energy
expended on reproduction versus that for sustaining the
body. It explains longevity in terms of optimum use of
resources available in the environment to a species to
maximise its reproductive success by not allowing
inefficient reproducers to divert resources to maintaining
their soma. It offers an explanation of the relationship
between longevity and reproduction strategies. No
overall theory explains diversity within similar species.
• The importance of Kirkwood’s theory is that it suggests
that there are no intrinsic genetic limits to human
longevity, if we come to cure one disease after the other
longevity will increase not hit a natural barrier.
“what are old people for?”
• Grandmother hypothesis. Why keep soma
well passed reproduction age? Answer is
obvious in human practices. Keeping
babies alive. Balance of knowledge
acquisition and adaptability, transmission
not fossilisation. Reconciled with
evolutionary arguments by emphasising
successful grandmothers spreading their
genes through the 25% contained in her
grandchildren.
Kinship as the basis for human society.
• Arguments for incest taboo as the origins of human society – i.e. the
basis for cultural construction of kinship, located in abstaining from
some and socially recognising some other forms of mating as
legitimate. Such cultural rather than biological regulation of mating
has the effect of creating clear succession of generations by
prohibiting mating between parents and offspring.
• However because we age, possible to have social division of labour
based not strictly on chronological age, which is a modern invention,
but on generation.
• Kinship as the basis of human society is based on categorising
relationships not only on gender but on generation. Generational
differentiation is embedded in the kinship terminology of all
societies.
• My argument is then, that as far as human society developed /
evolved from a kinship base so ageing and death, as the necessary
structure of generation succession, were essential.