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ISIS Report 30/04/07
Life & the Universe After the Copenhagen
Interpretation
The ultimate
reality beyond the Copenhagen interpretation of quantum mechanics is also beyond
ordinary physics. Dr. Mae-Wan Ho
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The quest for the ultimate reality of nature
Atoms and elementary particles
are the ‘stuff’ of nature, as far as western science is concerned. Thousands
of years have been dedicated to the scientific quest of discovering the most
fundamental particles of matter and to explaining nature in terms of those
particles.
In a way, the quest
came to an end when Max Planck identified the smallest quantum of action in
the constant named after him [1], and quantum mechanics was born.
The ‘Copenhagen
interpretation’ was the first general attempt to understand quantum mechanics
in terms of atoms and elementary particles [2, 3]. It was the work of Danish
physicist Niels Bohr together with Werner Heisenberg and Max Born from Germany
and others who made important contributions. However, Bohr and Heisenberg
never agreed on how the mathematical formalism of quantum mechanics should
be interpreted, and there is no definitive statement of the Copenhagen interpretation.
The Copenhagen interpretation and the
measurement problem
Nevertheless, the Copenhagen
interpretation is widely regarded as consisting of the following elements.
- A system is completely
described by a wave function that represents an observer’s knowledge of
the system.
- The description of
nature in quantum mechanics is essentially probabilistic as opposed to deterministic
in classical physics.
- Heisenberg’s uncertainty
principle ensures that it is impossible to know the values of all the properties
of the system at the same time; and those properties that are not known
with precision must be described by probabilities.
- Matter exhibits a wave-particle
duality; an experiment can show up the particle-like or the wave-like behaviour
of matter, but not both at the same time.
- Measuring devices are
essentially classical devices, and measure classical properties such as
position and momentum.
- The Correspondence
Principle says that quantum mechanical description of large systems should
closely approximate the classical description.
Most notably, the
Copenhagen interpretation denies that the mathematical formalism of quantum
mechanics has anything to say about what nature is really like, in particular,
as regards the central problem of measurement. The wave function of a physical
system evolves, according to the Schrödinger equation, into a linear superposition
(combination) of different quantum states encompassing all possibilities.
But actual measurement always finds the physical system in a definite state;
and this is referred to as “the collapse of the wave function.” The paradox
is usually presented as the parable of Schrödinger’s cat [4] (see Quantum
World Coming series, Science
in Society 22), imprisoned in a box with a capsule of deadly cyanide gas
that would be released the moment a radioactive nuclide decays. The cat is
therefore in a superposition of being alive, being dead, and being both alive
and dead at the same time until the box is opened, i.e., a measurement is
performed; at which instant, the cat is either dead, or alive.
There is thus a complete
discontinuity between the evolution of the wave function and the measurement,
what happens in the measurement that converts the probabilities to an actual,
sharply defined outcome is not explained by the theory. The Copenhagen interpretation
says we must not even ask that question, which is meaningless. As Aage Petersen
said in paraphrasing Niels Bohr [3]: “There is no quantum world. There is
only an abstract physical description. It is wrong to think that the task
of physics is to find out how nature is. Physics concerns what we can say
about nature.” And what we can say is not how nature really is.
The central problem of measurement
has provoked many alternative interpretations of quantum mechanics, some of
which takes us to the realm of ultimate reality, well beyond what ordinary
physics can say.
Mohrhoff’s
ultimate reality is eternal and unchanging and without properties
Ulrich Mohrhoff at
Sri Aurobindo International Centre of Education, Pondicherry, India, has presented
one interpretation of quantum mechanics that is rather appealing [4] (Beyond
the Central Dogma of Physics, this series). He departs from
the Copenhagen interpretation in so far as he rejects the ‘evolutionary paradigm’
of the wave function, and the ‘collapse’ of the wave function on measurement.
He goes beyond the Copenhagen interpretation as well as classical physics
in rejecting the usual description of reality in terms of atoms, particles
or ‘things’ underlying “manifest” phenomena.
Mohrhoff goes beyond science
into the realm of Indian Vedantic philosophy when he takes nature as One Being without properties, manifesting as “multiplicities”
that enter into spatial relations with itself, thereby “giving rise to [the
semblance of] both matter and space”. Or, as he qualifies in a later communication
[5]: “The multiplicity qua nothing but
multiplicity is an illusion. The multiplicity as a result of the One’s entering into relations with itself, presenting
itself to itself under a multitude of aspects, is not.” Of course,
it is not possible to test such an assertion, and it does remain in the realm
of belief, or cosmogony.
Mohrhoff rejects evolution
in the usual sense of the word. To him, the One (ultimate) Being is “ineffable”
and “infinite”, if not eternal and unchanging. It “plays Houdini” with itself
for the ‘fun’ and ‘excitement’ of it, manifesting as “the Adventure of Evolution”
[5].
In my opinion, the Mohrhoff
interpretation is not entirely self-consistent. A major difficulty is in seeing
how the One Being without properties
can conform to the mathematical formalism of quantum mechanics, which is quite
specific as well as paradoxical. This tells me that there is nothing arbitrary
about nature, i.e., it would argue against a nature without properties, or,
for that matter, a capricious God or Deity that merely “plays Houdini”.
Mohrhoff has later clarified
[5] he does not believe “there is anything
arbitrary about the physical laws.” Nature as world does have properties,
he says, but as “force responsible for
the existence of properties does not itself have properties.”
He then takes me to task
for proposing that the universe is quantum coherent [5] (see below). But ultimately,
we are in total agreement when he says, “I believe that none of the interpretative
frameworks of our present consciousness has an exclusive claim to truth.”
For me, the overriding importance
is how contemporary western science has recovered the unity of nature that has been taken for granted
by indigenous knowledge systems worldwide. And that is more than sufficient basis for a
new world order and transformation towards a better, more enlightened and
equitable world.
The
ultimate reality of a participatory creative universe
My own starting point
is also as a critic of the Copenhagen school of quantum mechanics, and not
as one who wants to defend or popularise it, as a casual reading of Mohrhoff’s
critique of my statements taken out of context might be misled into thinking.
I too have argued against
the collapse of the wave function [6, 7] ( Quantum Coherence and Conscious Experience, ISIS
scientific publication; The
Rainbow and the Worm - The Physics of Organisms 2nd Edition ), but from
a different scientific perspective. I go beyond conventional quantum mechanics
in proposing, on the basis of empirical evidence as well as theoretical considerations,
that the organism tends towards a “superposition of coherent space-time modes
(i.e., activities)”; and that the universe itself may also be quantum coherent,
like a superorganism, consisting of organisms that are mutually entangled
in such a way that each organism participates in every other [8] ( Quantum
Jazz, the Tao of Physics, this series). In this, I follow in
the footsteps of Alfred North Whitehead, who had argued persuasively that
quantum theory requires a thoroughly organic interpretation [9]. He saw the
entire universe as being composed of organisms ranging from elementary particles
to galaxies, although he had not considered quantum coherence, a universal
wholeness, which I believe necessary to complete his picture.
Indeed,
there is now experimental evidence that the wave function does not collapse,
and entangled states may survive ‘measurements’ or interactions with macroscopic
devices and scientists other than myself are suggesting that the universe
itself may be quantum coherent. So the Copenhagen interpretation may be wrong,
or at best incomplete; and one can reject it and still be agnostic about the
nature of ultimate reality.
But I
too, go beyond ordinary physics to the meaning of life and the universe. I
reject the notion that science, as knowledge of nature, is divorced from life
and the meaning of life. I see the universe developing and evolving, with
every organism participating, constantly creating and recreating itself anew.
It is a truly creative universe in that the future is not preordained, but
spontaneously and freely made by every single being, from elementary particles
to galaxies, from microbes to the giant redwood trees, all mutually entangled
in a universal wave function that never collapses, but like a constantly changing
cosmic consciousness, maintains and informs the universal whole.
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