Quantum
physics makes some people – especially those that seem to
understand it – uncomfortable. It suggests that at the base of
reality, things can be both here and not here, both particle and
wave, both one and zero. The
double
slit experiments,
in which electrons are sent in groups or individually through screens
with slits open or closed, show wave or particle features depending
upon the experimental set-up. Anything, small or large, can be
thought of as existing as a wave
function
with the probability that when measured the wave will collapse into a
definite object in a specific place as determined by the
probabilistic mathematics. (Large objects have the highest
probability of being where we see them, when we see them, rather than
anywhere else the wave may be spread out to, including perhaps in
another galaxy.) The picture of reality that quantum physics paints
is strange yet the mathematics of it – quantum
mechanics–
successfully predicts core elements confirmed by experimentation.
Niels
Bohr, who
was at the forefront of inventing the mathematics, said that it
requires a “radical
revision of our attitude toward the problem of physical reality.”
For Bohr, and others of
the Copenhagen
school, the
relationship of quantum physics to classical
physics
– the micro world to the macro – is
not straightforward.
Quantum mechanics accurately predicts outcomes at the level of the
very small where quantum affects lead to strangeness. Yet we seldom
see quantum effects at the macro level that is well-described by
classical
physics,
despite
its failure at the micro level.
One
of the stranger possibilities raised by quantum physics is the
role of the conscious observer.
This
interpretation posits that a wave function is collapsed when measured
and the measurement observed. (The role of the measuring
instrument
and whether it is part of quantum or classical reality is
one of the many issues still
debated.) Various
efforts have
been made to
sweep aside the difficulty of reconciling quantum and classical
physics and
avoid the messiness of assuming a tree is not there unless someone
sees it.
(This
problem
is
separate
from
attempts
to reconcile
quantum physics with relativity
or
to
unify
the fundamental forces and particles
of nature.)
One such
–
the
many worlds theory – suggests
that every time a
measurement is made, reality splits
into separate universes. A more parsimonious approach looks to the
concept of quantum
decoherence.
Essentially, wave functions spread out into each other and merge
into the world of classical physics. Strictly
speaking, this still leaves the question of the role of measurement
and the observer open. But some
believe
we need not accept any quantum strangeness because decoherence itself
leads to macro objects emerging from the micro reality. The quantum
waves crash onto the shores of observability by themselves. A tree
is there whether we see it or not.
The
questions here are profound.
One hundred million years ago, the earth was populated by dinosaurs.
Some very large creatures roamed the earth and we have found their
bones in our time. Surely they existed and moved through space and
time as discrete objects. They stepped over stones and across rivers
that also had a specific and real existence. Even before that, in
deep time,
before
multi-cellular life, primitive bacteria
and archaea
lived and reproduced and we’ve found their traces as well. They
existed without being measured or observed by any higher, conscious
living being.
So
does this mean that quantum strangeness is fake physics?
The
possibilities seem to be three:
– quantum
mechanics works well at the micro level but is unnecessary to explain
the reality of the world we see because it emerges
on it’s own whether we are
there or not to see it.
– nothing
emerges from the universal
wave function
(the equation encompassing the totality of existence across time and
space) as discrete objects until
observed.
– some
things exist as collapsed wave functions on their own while other
“things” exist only as the former interact with them.
The
first possibility simply begs the question of how two fundamentally
different pictures of reality can both be true. Rather, let
me suggest that
the second possibility may be a subset of the third.
Life
is the dividing line.
Rocks,
planets,
stars
and even
galaxies
exist as wave functions perhaps decohering as they spread out into
each other but still not
there
until acted upon – observed, eaten, stepped on – by something
acting as an individual
agent,
something alive and trying to stay alive and perhaps reproduce. Life
seems inevitable
given the fundamental constants of physics and chemistry. (Why the
universe is made this way is a
separate question.)
But a rock is just a rock and is never trying to become anything
else. It may be acted upon but doesn’t by itself act. A tree is
always there because it is trying to be. It acts
upon
its surroundings with purpose thus
collapsing its own wave function and those with which it interacts.
It transforms earth and sunlight into living tissue, its own living
tissue. This may imply or even require a certain kind of
consciousness. Certainly, it does suggest awareness of
environment sufficient to utilize it.
How is a tree’s awareness different from our own? That is another
matter. But
a tree is there even if alone its forest.
