This used to
be a very profound question till recently. Developments in physics during the
last few decades have now made it rather trivial and trite.
Such questions
used to be in the domain of philosophy, and human history can boast of a truly
dazzling succession of great philosophers. But the question now is: What is the
true worth of an otherwise great philosopher who was/is innocent about the finer
points of quantum mechanics?
Modern physics
has come up with plausible answers to fundamental questions over which
philosophers fretted for centuries. No wonder, Hawking & Mlodinow wrote this in 2010, somewhat facetiously perhaps:
Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept up with developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge.
An answer to
the question 'Why are the laws of Nature what they are?' comes from M-theory
(cf. Part 14). According
to it, there are actually 11 dimensions. We see only four because the rest of
them have got 'curled up' so much that they are not visible to us. There are
~10500 different modes of curling up, meaning that that many
different universes are possible. One of them is the universe we inhabit. The
apparent laws of a universe depend on how the extra dimensions in that universe
got curled up. We say ‘apparent laws’, because the more fundamental laws are
those of the M-theory.
Thus, there
are multiple universes, or MULTIVERSES, each with its own set of apparent laws.
We just happen to be living in a universe with a certain set of laws and a
certain set of values for the fundamental constants. If the laws of a universe
are not conducive to emergence and evolution of life, living beings cannot
possibly exist in that universe, discussing such questions.
In Newtonian
physics, the past was visualized as a definite series of events. Not so in
quantum physics. No matter how thoroughly and accurately we observe the
present, the unobserved past, as also the future, is indeterminate, and exists
only as a ‘spectrum of possibilities’. This means that our universe does not
have just a single past or history. Since the origin of the universe was a
quantum event, Feynman’s sum-over-histories formulation for going from
spacetime point A to spacetime point B occupies centre-stage (cf. Part 4). But we have
knowledge only about the present state of the universe (point B), and we know
nothing about the initial state A. Therefore, as emphasized by Hawking, we can
only adopt a ‘top down’ approach to
cosmology, wherein every alternative history of the universe exists simultaneously,
and the histories relevant to us are those which, when summed up, have a high
probability of giving us our present universe (point B).
The picture
that emerges is that many universes emerged spontaneously (simultaneously or
otherwise). Most of these universes are not relevant to us because their
apparent laws are not conducive to our emergence and survival. The M-theory
offers ~10500 possibilities of start-up universes. We have to single
out those which correspond to the curling up of exactly those dimensions which
we find to be the case for the universe we inhabit. Further, we have to select
those histories which reproduce, for example, the observed mass and charge of
the electron, and other such observed fundamental parameters.
WHAT IF THE
M-THEORY DOES NOT GET DUE VALIDATION? The multiverse idea would be still
intact; via the cosmic-inflation theory (cf. Part 17). The inflation episode is an integral part of modern cosmology.
It is now time
to recapitulate some points I have made in these 19 posts. First I gave purely
classical arguments to explain how our universe could emerge out of 'nothing',
without a violation of the principle which says that the total mass/energy is
always conserved, and that nothing extra can get created. This classical
argument is simple to understand, but is, at best, only a crude statement. The
real explanation has to come from the laws of quantum mechanics, because these
laws govern all natural phenomena. The vacuum state in quantum field theory is
not at all a state of 'nothingness'. It has an energy of its own. Our universe
emerged out of vacuum as a quantum fluctuation, without violating the principle
of conservation of energy/mass. And the M-theory and the cosmic-inflation
theory are powerful explanations for why our universe has the laws it has. Our
universe got created in accordance with the laws of physics (or rather because
of them), without the help of a Creator.
Euclidean
geometry holds true in our universe; i.e., ours is a flat-geometry
universe. Which is just as well. As explained in an accessible language in a
recent book 'A Universe from Nothing', only a flat-geometry universe can satisfy the
requirement that the sum total of positive and negative contributions to the
overall energy of the universe add up to zero. The energy-conservation law was
not violated when our universe emerged out of 'nothing'. The total energy is
still zero.
Watch this
video for more:
The next set
of posts in this series will explain how life emerged out of non-life, without
any help from a Creator or Designer. It was all a matter of evolution of 'complexity' in an
expanding and cooling (and therefore gradient-creating) universe. At our
terrestrial level, the steady ingress of solar energy into our ecosphere has
been the local factor creating gradients or non-equilibrium situations. The
natural tendency to seek equilibrium configurations often leads to new patterns
and structures. This is how 'complexity' evolves. The emergence of life in one
such example of what thermodynamically open systems can achieve. There is
nothing divine or mystical about that.
From now on
the narrative will become more and more life-centric and anthropocentric. In
the next post I shall discuss the Anthropic Principle.
I think just like God which is a popular notion for General Public to answer questions that seem intractable the more sophisticated version will be of Philosophers. Both emerge at one level from Gods of Gaps. That is why both the Philosophers (Newton included) and the Church ( Trans Religious way) posit God for what they term as "WHY" questions. Historically Science did not have any real answers at each of those epochs. And to put is as I think Krauss put it Science can only answer questions that are WELL POSED. So as science is able to convert the so called "WHY" questions to as well posed questions we start getting scientific answers with no reference to GODS ( see Tyson).
ReplyDeleteThanks Rajesh. I agree with you entirely. I shall dwell on it some more in the next post.
ReplyDelete