The second hard problem of modern science is the origin of consciousness or the problem of free will. This post focuses on the relation of this problem with quantum mechanics. As an example of the difficulty of the matter, I begin by including two famous quotes from renowned scientists:
·
J.
B. S. Haldane, Possible Worlds (1927): The universe [of quantum theory] is, not only queerer than we
suppose, but queerer than we can suppose.
· James Jeans, The Mysterious Universe (1930): The universe begins to look more like a great thought than a great machine.
The Copenhagen interpretation of quantum mechanics,
championed by Niels Bohr and his school, asserts that the physics of elementary
particles is not deterministic, but random. Elementary particles, atoms, the
components of the microscopic world, do not have properties with fixed values (a
positive or negative magnetic moment, a certain spin direction—related to the
rotation of the particle), but rather all the possible values simultaneously.
When we measure one of these properties, the particle or atom chooses a specific value from among all possible values.
This is called the quantum
collapse. Before
the measurement is made, it is impossible to predict its outcome (the result of
the quantum collapse).
It is true that the Schrödinger equation, which describes the behavior of elementary
particles before quantum collapse, is deterministic. But quantum
collapse, which
serves as the interface between microscopic quantum phenomena and classical
macroscopic phenomena, according to the Copenhagen interpretation, is indeterministic.
The Copenhagen interpretation has been predominant
in quantum physics throughout the 20th century. Many attempts to overturn it
have failed. To salvage determinism, the only option left for its proponents is
to replace it by another interpretation that does not imply physical
indeterminism. So far, all such proposals, championed by Einstein, David Bohm,
and other renowned physicists, have failed.
John von Neumann and Eugene Wigner went a step
further, proposing an interpretation of quantum mechanics according to which
the collapse of the wave function is caused by a conscious observer making a
measurement. In his book Interpretation of Quantum Mechanics (1976), Wigner wrote this:
When the
province of physical theory was extended to encompass microscopic phenomena
through the creation of quantum mechanics, the concept of consciousness came to
the fore again. It was not possible to formulate the laws of quantum mechanics
in a fully consistent way without reference to the consciousness.
If this interpretation were true, the consequences
would be huge: it would mean that no quantum collapse could have occurred
before the emergence of conscious beings in the universe. Until then, the
entire universe would have been in a state of multiple quantum superposition; thus,
no objective reality would have existed. The following two quotes illustrate
this:
·
John
Wheeler, in the 1970s, drew an eye observing the evidence for the Big Bang and
asked: Does looking back 'now' gives reality to what happened 'then'?
·
Martin
Rees: In the beginning there were only
probabilities. The universe could only come into existence if someone observed
it. It does not matter that the observers turned up several billion years
later. The universe exists because we are aware of it.
In fact, few physicists accept the von
Neumann-Wigner interpretation, and to avoid it, they claim that the existence
of quantum collapse does not require the intervention of a conscious being, but
rather occurs as a result of any interaction between the microscopic and
macroscopic worlds, where quantum superposition does not appear to be possible.
But this latter claim is not universally accepted by physicists.
 |
| Roger Penrose |
On the other hand, some theories assert that
quantum mechanics makes free will possible, enabling the interaction of the
human mind with the physical world and making us agents endowed with
intentionality and free will. Some, as the ORCH-OR theory proposed by Penrose and Hameroff, point out where
consciousness interacts with our neurons (in the microtubules of neurons), but
although I
have collaborated with Hameroff, that theory doesn't quite convince me.
But let's suppose for a moment that the Von
Neumann-Wigner interpretation were correct. The relationship between quantum
mechanics and consciousness would be twofold, as shown in the figure at the beginning of this post:
1.
On
the one hand, the observer's consciousness would be necessary for quantum
collapse to take place.
2.
On
the other hand, quantum collapse would make possible our conscience and free
will.
A recent book studies this problem in detail. Its
title is Quantum Enigma, written by Bruce Rosenblum and Fred Kuttner. In light of Wigner's
interpretation, it describes the enigma of quantum theory and its skeleton in the closet: Does this theory imply the influence of
consciousness on reality?
Let us look at a few quotes from this book:
Though the
quantum enigma has confronted physics for eight decades, it remains unresolved…
We physicists might therefore approach the problem with modesty—though we find
that hard.
[M]ight
Einstein’s original suggestion of a cosmological constant
have caused the acceleration of the universe? (Such a speculation
can’t be proven wrong. It is therefore not a
scientific speculation.) Though taking an idea like this literally is
surely ridiculous, we see how outrageously the quantum enigma allows one to
speculate.
Quantum
theory tells us that physics’ encounter with consciousness… applies, in
principle, to everything. And that “everything” can include the entire
universe. Copernicus dethroned humanity from the cosmic center. Does quantum
theory suggest that, in some mysterious sense, we are a cosmic
center?
The authors of Quantum Enigma offer an interesting counterexample to refute
those who deny the reality of free will because we cannot prove that others
have it. They say: Counter to that argument, though you can’t demonstrate your
feeling of pain to someone else, you know it exists, and it’s certainly not
meaningless.
For me, the most striking support for our having free
will, is the fact that God asked for Mary’s permission before becoming
incarnated in her womb.
Thematic Thread about Natural and Artificial Intelligence: Previous Next
Manuel Alfonseca
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