Hier een kritische maar gedetailleerde review van een Christen fundamentalistische fysicus:
quote:
Despite the fact that Stephen Hawking's book with Leonard Mlodinow, The Grand
Design, begins by intoning, "Philosophy is dead," many physicists recently, not
least Hawking himself, have ventured to make many controversial philosophical
speculations going far beyond the science that is presently well understood.
Lawrence Krauss's latest book, A Universe from Nothing: Why There Is Something
Rather than Nothing, falls into this category. Chapters 2-8 are a nice
popularization of much of what we have learned in cosmology (modulo a few
technical details) and are well worth reading. (I would have given four stars
if the book had just included these chapters and had a reasonable title.)
But in my mind as another physicist working in the same general area of cosmology
(and perhaps focusing deeper into the quantum aspects of cosmology),
its philosophical argumentations fall far wide of the mark of answering
the age-old question of why there is something rather than nothing.
Krauss essentially redefines the ancient difficult question into different forms
that science can address, discusses possible solutions to the restricted questions
(themselves highly speculative, as Krauss carefully recognizes), and then seems
to imply that these speculative answers to the restricted questions solve
the ancient difficult problem.
As I would put it, the question of why there is something rather than nothing is
the question of why there is anything not logically necessary (something) rather
than not anything not logically necessary (nothing). True theorems of
mathematics (the logical following of the conclusions from the axioms, not the
axioms or conclusions themselves, which might be neither true nor false, such as
the axiom of choice, which can consistently be either assumed or negated) seem
to be logically necessary, true in all logically possible worlds, so I am
excluding them from being counted as `something,' since otherwise it would seem
obvious that these supposed `somethings' must necessarily exist. However,
entities like elementary particles, atoms, molecules, sand grains, rocks, life,
sex, people, money, books, book reviews, memes, computers, internets,
universities, nations, continents, planets, stars, galaxies, electromagnetic
fields, space, time, quantum states, quantum operators, quantum probabilities,
particle masses, coupling constants, laws of physics, observations, conscious
perceptions (or sentient experiences), and even God in my view (though many
disagree) are not, so far as I can see, logically necessary, so they are
`somethings' in my sense. They are somethings whose existence has long been
mysterious. Why do any of these entities exist, if there is no logical
requirement that they must?
Krauss nicely tells how the laws of physics and the existence of a quantum state
with a region of space and time containing an electromagnetic field (or
containing the gravitational field of a black hole) can lead to the evolution of
the quantum state from having no particles at one time to a quantum state having
particles at another time. If only particles are counted as `something,' so
that the situation with `only' the laws of physics, space, time, and an
electromagnetic field or black hole but no particles counts as `nothing,' then
indeed these are cases in which we now understand scientifically how `something'
can arise from `nothing.' However, it is a very strong restriction of
`something' to exclude laws of physics, space, time, and electromagnetic and
gravitational fields.
Krauss goes on to discuss how it might be possible to obtain a scientific
understanding of how a situation even without space and time can lead to a
situation with space, time, fields, and particles, though again he implicitly
assumes some laws of physics and a suitable quantum state. This case has a
subtlety that Krauss does not discuss, in that if one considers a situation
without time, what is meant by saying that another situation with time arises
out of it? It can hardly be by the time evolution that was assumed in the case
of existing space and time with fields that produce particles at a later time
that may not exist at an earlier time.
One view of quantum gravity, particularly in what is called canonical quantum
gravity (though it has problems not fully understood), is that different times
are different components of the quantum state (which may also have components
with no time, and perhaps even with no time and no space). In this view in
which time is rather emergent (part of some components of the quantum state,
like wetness for water molecules that might not be considered to exhibit this
property when in isolation), time is not fundamental, so there is no evolution
from one component of the quantum state to another, and certainly not from a
component without time to a component with time. Then one would just say that
the full quantum state has some components without time, and other components
with time. So even if one chose not to count the quantum state as `something,'
one could hardly say that time arose in the sense of time evolution from
non-time, but rather simply that both components without time and components
with time exist within the full quantum state. Without time and time evolution,
it also appears to be an oxymoron to say, as the title of Chapter 10, that
"Nothing is Unstable."
Now it might be true (though we certainly do not know yet) that unknown laws of
physics, including both the dynamical laws (how things evolve with time if there
is time, or more generally in quantum theory, the algebra of quantum operators)
and the boundary conditions (which solution of the dynamical laws describes our
universe or multiverse, or which quantum state it has if quantum theory is
indeed correct), determine that parts (components) of the quantum state have no
time or space or particles, and that other parts do have time and space and
particles. Restricting `somethings' to, say, time, space, and particles, one
might say that the complete quantum state has both `nothing' and `something,'
but even with this restricted sense of `something,' it is rather a strained
interpretation to say that the `something' part arose out of the `nothing' part;
both simply exist within the total reality. In any case, the laws of physics
(both the dynamical laws and the quantum state) are here being implicitly
assumed to exist, and it certainly seems unfair to dismiss them as `nothing.'
Krauss goes on to speculate that "there may be no fundamental theory at all"
(page 177), perhaps that there are not even fundamental laws of physics, but
that the laws we deduce arise from a situation without laws. This is certainly
speculation (though I do not want to imply that Krauss is suggesting that it is
not speculation) going far beyond present science, since by what meta-laws or
processes could laws arise from non-laws? Krauss seems to have in mind current
ideas of the multiverse, in which the entirety of our physical reality (let me
call it the universe, even if it is a multiverse) has highly varied parts, say
with different particle content, particle masses, and coupling constants that
might be considered to be part of local `laws of physics' or `bylaws' for that
part of the universe. It is an interesting question, now being addressed within
superstring/M theory and its apparent string landscape, how an overall
superstring/M theory (not yet fully known) might lead to different parts of the
universe (pocket universes or sub-universes) having different local bylaws of
physics. In this way the local bylaws might indeed arise from the global laws
for the entire universe.
But so far there is no convincing evidence I am aware of that there are not
global laws for the entire universe or multiverse, even if these laws do not
lead to unique laws for the sub-universes. I see the scientific attractiveness
of the multiverse hypothesis as arising from the idea that the laws for the
entire multiverse might be simpler and more elegant than the laws for our
individual sub-universe, not that there are no laws at all for the entirety.
In his preface, Krauss admits that philosophers and theologians have objected to
his meaning of `nothing' and claim that he does not understand it. Krauss's
initial response is to make the gratuitous ad hominem reply, "I am tempted to
retort here that theologians are experts at nothing." He then says that for
them, "Nothing is `nonbeing,' in some vague and ill-defined sense." Well, even
though I am a scientist rather than a philosopher or theologian, on this issue I
agree with them and think that the idea of nothing as the absence of anything
not logically necessary is much more precise and well-defined than Krauss's
imprecise ideas of `nothing,' such as "the absence of space and time itself".
(If space and time are emergent properties, how does one define precisely their
absence? How can one define precisely the absence of emergent approximate
properties like wetness?)
Although I have focused on the philosophical ideas of nothingness that Krauss
does seems to engage with more by ridicule than by understanding, I also
disagree with his anti-theistic remarks, such as his referring on page 173 to "a
remarkable all-powerful entity for which there is simply no other evidence." In
contrast to this, the existence of an omnipotent God seems to me to be the
simplest explanation for the strong historical evidence for the resurrection of
Jesus, for example as recently summarized by the masterful historical treatment
by N. T. Wright in his 817-page analysis, The Resurrection of the Son of God.
So what Krauss wrote here is a gross overstatement.
Now my objection to this error should not be mis-interpreted to be an objection
to honest doubt and skepticism, which are indeed helpful in both science and
religion in getting closer to the truth, and I do appreciate other places in the
book where Krauss seems more honest in his skepticism and less dogmatic about
lack of contrary evidence. If the phrase I quoted had been written something
like the following, I would not have objected: "a remarkable all-powerful
entity for which I personally do not see convincing evidence." But to say, in
the face of the massive historical evidence that Jesus' disciples believed that
they had witnessed his empty tomb and personally had seen him resurrected from
death, that there is no other evidence for God, sounds woefully ignorant of the
facts. I personally would advocate skepticism toward unsubstantiated beliefs
that "there is simply no other evidence" for God.
In his final paragraph of his Afterward, Richard Dawkins makes the prematurely
triumphalist statement, "And now we can read Lawrence Krauss for what looks to
me like the knockout blow." To me as a fellow scientist, it appears Krauss has
instead swung far wide of the goal, striking only the air with his philosophical
speculations that do not address the truly deep questions of existence.
Don N. Page
Professor of (theoretical gravitational) Physics
University of Alberta
profdonpage@gmail.com
Het probleem is dat het postuleren van een God als alternatief nog meer vragen oproept, minder bewijzen heeft, minder voorspellingen doet en nog minder falsifieerbaar is dan de diverse wetenschappelijke hypothesen.
Ik denk dat de kennis over het ontstaan van het universum nog niet volwassen genoeg is om de vraag te beantwoorden dus het kosmologisch argument dat hiervan afhankelijk is werkt ook niet.