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- My perspective of David Deutsch's The Fabric of Reality
- Revised 13Oct1999. See note 1.
- To you reader: Note that this is an original review
by Renselle. It is four hundred words longer than a review which
appears on http://www.amazon.com/.
In The Fabric of Reality David Deutsch chisels his place
among new young geniuses entering Millennium
III. Humankind shall benefit from his keen intellect, fresh
memes, and bold strokes. He prods us and classical legacy-addled
physicists to drop our one-universe chauvinism in favor of Hugh
Everett's multiverse. Like all humans, though, his greatness
complements his imperfection.
Chapter one ends with this ken of Deutsch's personal crux:
"I now think that the important issue is not really whether
what our particular species understands can be understood by
one of its members. It is whether the fabric of reality itself
is truly unified and comprehensible. There is every reason to
believe that it is. As a child, I merely knew this; now I can
The Fabric of Reality is about a need to unify four complementary
threads: 1) quantum theory, 2) evolution theory, 3) computation
theory, and 4) epistemology. Deutsch believes that these four
threads are co-synthetics of a theory of everything which leads
first time to a "last great unification" making it
ultimately possible for an individual quantum-multiverse-supported
human intellect to explain everything.
It was not Deutsch's intention, but you may see his four threads
as violin strings much like Prince Louis de Broglie's metaphor.
Until now, his strings have been in a heap, so to speak, just
loosely lying about. But Deutsch offers a framework genesis
a new violin body. You can envision a fledged frame: his
new system of thought with four strings carefully strung, tuned
and sympathetically united in a resonant violin body. It is up
to theorists and technologists to play this instrument, to make
more beautiful, harmonious music in this fecund complement of
both freedom and confinement.
We see Deutsch's greatness in his stronger points which are:
superiority of quantum science, our multiverse as a repository
of growing knowledge, a philosophical and scientific failure
of inductivism, his proposed use of virtual reality to prototype
theories, imminence of quantum computation, his unification of
determinism and non-determinism, and his brief but elegant weaving
of all four threads.
Rightly, Deutsch calls quantum science our best and most accurate
science of reality humankind has at this moment. By comparison,
he decries classical and space-time sciences' inaccuracy and
diminishing usefulness for Millennium
III. He denigrates space-time science as "false,"
and classical science as "obsolete." Their replacement
is a great subsumer: quantum theory and its descendants.
We cannot disagree. Bravo!
Appropriately, Deutsch destroys inductivism, positivism, instrumentalism,
reductionism, solipsism, and mathematical intuitionism. They
are inutile tools for quantum
logic. His destruction of inductivism, however germane, appears
to rest on his perception: observation is a parent of
evil "historical evidence." He rails against historical
evidence in his extensive dialogue against inductivism.
From a quantum perspective, his single greatest achievement in
his book is not unification of all four threads, but his superb,
simple, multiple explanations of interference using pinholes,
shadows, multiple slits, and semi-silvered mirrors. His explanations
are easy to understand and provide convincing 'explanatory' evidence
of our multiverse.
Deutsch, magnificently, and in open defiance of Einstein's general
relativity unifies determinism and nondeterminism. He does this
by first declaring that all universes in our multiverse are determinate,
and second declaring most entities experiences are indeterminate
in our multiverse because they make choices. Each entity's choices
select different thread segments (snapshots) in its journey through
our multiverse. Neat idea, but I worry neo quantum mechanics
may find his determinate-universes-in-the-multiverse view still
too static and objectivist.
Deutsch's weaker points include a youthful and refreshing arrogance
perhaps best depicted by his claim that he can (does) explain
physical reality. He puts himself in hot water here by claiming
he can put any concept in a framework and then explain it, thus
gaining understanding. Later he goes on to say time has no framework,
from which you reader must infer it cannot be explained. This
seemed to expose a large gap in his framework-explanation method
for understanding physical reality.
Too, and unfortunately,
Deutsch makes some claims with which I doubt many quantum mechanics
would agree, e.g.: "biological variations are random,
blind, and purposeless," and, "there is no biological
equivalent of argument." This sounds like old, classical
stuff. I suspect Brian D. Josephson, in particular, might find
these remarks suspect from a quantum biology perspective. One
faux pas which left this reader incredulous is his repeated statement,
"My bet is that a human brain,
considered as a computer, is a classical one [not
a quantum one]." Considering a quantum fundamental:
quantum systems compose physical reality his bet appears
a likely loser.
Deutschs style is nearly stream of consciousness writing.
He practices unannounced subtle context switches which are difficult
to follow. I was left wanting for lack of multiple, context-managed
stack registers to follow most of Deutsch's work. I think he
is so smart it is difficult for him to stay at a lower level
where most of us reside. It is probably ill-used effort for him
to unencumber his context flux for us. We readers just need to
get a lot smarter!
Sadly, Deutsch invests incredible time, energy, and space on
a dialogue with a crypto-inductivist explaining base inadequacies
of inductivism. He goes on to declare himself neither an inductivist
nor a crypto-inductivist then boldly manifests his own regressive
crypto-crypto-inductivism. Subsequent to this declaration he
avers historical evidence and historical frameworks frequently
to explain his conclusions. One clear example of his regress-inductivism
is his inductive argument against inductivism, "
present theories say that the future will not resemble the past."
Perhaps this is a test to see if we understand his chapter on
Finally I think he carries legacy baggage of classical science's
subject-object dichotomy. He throws out classical science, but
retains its old umbrella classical metaphysics. I guess this
arises from his faith in Popperian philosophy. His four strands
are all intellectual patterns of value and thus intrinsically
subjective, but he insists on 'justifying' them objectively by
giving them 'substance' through explanation in a classical framework.
Somewhat redeeming grace, he mitigates classical objectivism's
downside via his acknowledgment of his scientific method's provisional
nature and his strong (and I believe correct) position on existence
of our quantum multiverse (thus admitting multiple frameworks
and concomitant multiple truths) which denies classical sciences
faulty goal of universal truth.
My big question for David Deutsch is, "Is a reality in which
a finite intellect can comprehend everything more real than a
reality in which a finite intellect humbly acknowledges there
is always more than finite intellect can comprehend?"
To an expectant and careful reader's dismay Deutsch avoids several
ü Waves (His multiversal interference
appears wholly particulate-objective. See Note
ü Complementarity (Probably
because a Copenhagen interpretation prefers a single universe.),
ü Superluminality (Deutsch
must assume this to achieve zero-latency multiversal interference.),
ü Evolution as a consequence
of observation (I.e., Niels Bohr, Copenhagen-like observation.
Deutsch sees evolution as a consequence of choices. When one
thinks carefully about this, choice is a subsequent to perception
which is a subsequent to observation.),
ü Observation as a special
event (Deutsch usurps an 'observation' meme with a 'choice' meme.),
ü Context freeness of formal
logic as both its major strength and its major weakness, and
ü Whether a classical subject-object
dichotomy is a proper framework for physics (Deutsch very blatantly
assumes that it is.).
One can only surmise his philosophy denies relevance of these
topics in his treatise. His adapted Popperian philosophy appears
to contravene relevant artifacts of orthodox Copenhagen quantum
theory. I think a unification of Deutschs ideas and selected
Copenhagen concepts which he dismisses are superior to either
Conclusion: You should read this book. Then ask yourself,
"What political motivation won it a Dirac Prize?"
- Deutsch recently appeared on a PBS science show (CDT 8PM, 12Oct99),
and he still sees reality from an objective viewpoint. He and
a colleague demonstrated a classical double-slit experiment with
multiple photons traversing both slits and (unmeasured) forming
familiar interference fringe patterns on a screen. They revise
their experiment to only permit successive incremental delivery
of unit photons to traverse both slits. One intuits their expectation
of a non-fringe particulate spot pattern on a screen (i.e., what
we would see if we attempted to measure either or both slits to
see which slit a photon object is traversing). However, a familiar
interference fringe pattern integrates gradually with each new
photon's traversal. Deutsch exclaims, "Since photons are
objects our results are impossible unless our individual photons
are interfering with photons from other, parallel multiverses."
Here, we see Deutsch still denying photons and in general,
quantum systems are wavicles. He tells us a photon cannot
be in more than "one place, one locus" at a time. He
tells us that to make that assumption would be absurd!
His simple "one place, one time" statement describes
a classical analytical thing. Analytical things (i.e., classical_object
= f(t), or in words, classical objects are ideal infinitesimal
point functions of time) are innately incapable of interference.
'Orbits' of classical objects decay! Analytical things are incapable
of Heisenberg uncertainty (inter)relations. Analytical things
are incapable of depicting quantum reality. Analytical things
(assuming Einsteinian relativity) are incapable of superluminality,
tunneling, etc. All of this argues against an object model capable
of interference with itself or, as Deutsch suggests, another multiversal
See our review of Irving Stein's, The
Concept of Object as the Foundation of Physics.
We are simply amazed! All of quantum science and nearly unlimited
and various experiments with various simple quantum systems are
interpreted to infer multiversal omnimensionality plus both/and
particle/wave nature of all quantum systems. Yet Deutsch tells
us that an individual photon, as an objective particle, cannot
interfere with itself, but somehow it can interfere with other
objective photons both in a local multiverse and in nonlocal multiverses.
Did you get that? A photon cannot interfere with self locally,
but it can interfere with nonlocal objects in other multiverses!
Bottom line: We still think Deutsch's difficulty is his assumption
of an analytic, objective reality. In our opinion, objectivism
is a paralytic disease of otherwise great minds. Return
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©Quantonics, Inc., 1998-2024 Rev. 18Sep2013
PDR Created 12May1998 PDR
(21Dec2000 rev - Add local link to 'absurd'
(24Jan2001 rev - Use ext-dashes in para. 2 of note above to correct
(19Dec2001 rev - Add top of page frame-breaker.)
(16Oct2006 rev - Replace 'omni[di]mensional' with 'omnimensional.')
(16Jan2011 rev - Add 'Deutsch Mind as Classical Computer' anchor.)
(18Sep2013 rev - Make page current.)