These are excerpts and elaborations from my book "The Nature of Consciousness"
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The Laws Of Nature Revisited How biology relates to the
rest of the universe is less clear. This universe exhibits an
impressive spectrum of natural phenomena, some of which undergo spectacular
mutations over macro or micro-time (long periods of time, or short periods of
time). Life deserves a special status among them for the sheer quantity and
quality of physical and chemical transformations that are involved.
Nonetheless, ultimately life has to be just one of them. Indirectly, it was Charles
Darwin who started this train of
thought, when he identified simple rules that Nature follows in determining how
life proceeds over macro-time. While those rules greatly differ from the laws
of Physics that (we think) govern the universe, they are natural laws of equal
importance to the laws of electromagnetism or gravitation. Why they differ so much from
the others is a matter of debate. It could be that Darwins laws are gross approximations of laws that, when discovered, will
bear striking resemblance to the laws of Physics; or, conversely, maybe the
laws of Physics are gross approximations of laws that, when discovered, will
bear striking resemblance to the laws of evolution; or maybe they are just two
different levels of explanation, one set of laws applying only to the
micro-world, the other set applying to the macro-world. A key aspect of life is that
all living systems are made of the same fundamental constituents, molecules
that are capable of catalyzing (speeding up) chemical reactions. But these
molecules cannot move and cannot grow. Still, when they are combined in
systems, they grow and move. New properties emerge. The first new property is
the ability to self-assemble, to join other molecules and form new structures
which are in turn able to self-assemble, triggering a cycle that leads to
cells, tissues, organs, bodies, and possibly, societies and ecosystems. In order to approach the
subject of life in a scientific manner, we first need to discriminate among
the various meanings of that term. What we normally call life is actually
three separate phenomena. Precisely, in nature we observe three levels of
organization: the phylogenetic level, which concerns the evolution over time of
the genetic programs within individuals and species (and therefore the
evolution of species); the ontogenetic level, which concerns the developmental
process (or growth) of a single multicellular organism; and the epigenetic
level, which concerns the learning processes during an individual organism's
lifetime (in particular, the nervous system, but also the immune system). In other words, life occurs
at three levels: organisms evolve into other organisms, each organism changes
(or grows) from birth till death, and finally the behavior of each organism
changes during its lifetime (the organism learns). There are therefore two
aspects to the word "life". Because of the way life evolved and came
to be what it is today, life is both reproduction and metabolism: it is both
information that survives from one individual to another
("genotype"), and information about the individual
("phenotype"). When we say that "ants are alive" and
"I am alive" we mean two different things, even if we use the same
word. To unify those two meanings it takes a theory that explains both life as
reproduction and life as growth. Back to the beginning of the chapter "The Evolution of Life: Of Designers and Design" | Back to the index of all chapters |
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