These are excerpts and elaborations from my book "The Nature of Consciousness"
Somehow
asymmetry seems to play a protagonist’s role in the history of our universe and
our life. Cosmological models speculate that the four fundamental forces of
nature arose when symmetry broke down after the very high temperatures of the
early universe began to cool down. Today, we live in a universe that is the
child of that momentous split. Without that “broken symmetry” there would be no
electrical force and no nuclear force, and our universe would be vastly
impoverished in natural phenomena. Scientists have
also speculated at length about the asymmetry between matter and antimatter: if
one is the mirror image of the other and no known physical process shows a
preference for either, why is it that in our universe protons and electrons
(matter) overwhelmingly prevails over positrons and antiprotons (antimatter)? Most physical
laws can be reversed in time, at least on paper. But most will not. Time
presents another asymmetry, the “arrow of time” which points always in the same
direction, no matter what is allowed by Mathematics. The universe, history and
life all proceed forward and never backwards. Possibly related
to it is the other great asymmetry: entropy. One can't unscramble an egg. A
lump of sugar which is dissolved in a cup of coffee cannot become a lump of
sugar again. Left to themselves, buildings collapse, they do not improve. Most
artifacts require periodic maintenance, otherwise they would decay. Disorder is
continuously accumulated. Some processes are irreversible. It turns out
that entropy is a key factor in enabling life (and, of course, in ending it).
Living organisms maintain themselves far from equilibrium and entropy plays a
role in it. Moreover, in
1848 the French biologist Louis Pasteur discovered that aminoacids (which make up proteins which make up
living organisms) exhibit another singular asymmetry: for every aminoacid there
exist in nature its mirror image, but life on Earth uses only one form of the
aminoacids (left-handed ones). Pasteur’s mystery is still unexplained (Pasteur
thought that somehow that “was” the definition of life). Later, biologists
would discover that bodies only use right-handed sugars, thereby confirming
that homochirality (the property of being single-handed) is an essential
property of life. Finally, an
asymmetry presents itself even in the site of thinking itself, in the human
brain. The two cerebral hemispheres are rather symmetric in all species except
ours. Other mammals do not show preferences for grasping food with one or the
other paw. We do. Most of us are right-handed and those who are not are
left-handed. Asymmetry seems to be a fundamental feature of our brain. The left
hemisphere is primarily used for language and the interplay between the two
hemispheres seems to be important for consciousness. It may turn out
to be a mere coincidence, but the most conscious creatures of our planet have
also the most asymmetric brains. Was there also a
unified brain at the origin of thinking, whose symmetry broke down later on in
the evolutionary path? Back to the beginning of the chapter "The New Physics" | Back to the index of all chapters |