There is beauty... in sky and
cloud and sea, in lilies and in sunsets, in the glow of bracken in autumn and
in the enticing greenness of a leafy spring. Nature, indeed, is infinitely
beautiful, and she seems to wear her beauty as she wears color or
sound. Why then should her beauty belong to us rather than to
her?
These lines portray an exquisitely beautiful picture of
nature and expound the idea that nature, by itself, has certain inherent properties and
intrinsic values. Like blueness is inherent to sky and redness to rose, there
are some facts and properties which are obstinately integral to nature and its
underlying reality. But does the reality indeed have an objective value or is it
a subjective response of the human mind? Does it perpetually exist independent
of an observer’s perspective or does it cease to exist outside the context of a
spectator?
When I look at grass, I find it green. So, does that
mean that the grass is green? No doubt, we judge greenness without having any
liberty to refuse it. But if one makes way into the grass till the sub-atomic
realm, he will find that there the grass does not look green at all. There are
electrons buzzing around and the grass which appeared mostly solid is now
mostly empty. He might even observe some quantum weirdness there but everything
he observes is very unlike the grass he saw earlier. So, is the grass really
green? Is it really solid as it appears? A sensible answer would be that the
grass, indeed, is not green and not solid and in reality, is made up of
sub-atomic particles, doing their own business at their level. Since we happen
to see it from a distance, we see it solid (an averaged out behavior) and since
it mostly bounces off photons whose lengths lie around 550 nm, we see it as
something greenish (a trait which living beings acquired during evolution to
distinguish photons of different lengths).
Let us take another example. When we eat sugar, we find
it sweet. But is sugar, whose one molecule is made up of 12 carbon atoms, 22
hydrogen atoms, and 11 oxygen atoms, really sweet? The answer is no. It is the
shape of sucrose molecule interlocked with the receptors on the tongue, which
is experienced as sweetness.
The examples above bring home the point that the
greenness of the grass or the sweetness of the sugar is nothing but a gift or
should I say rather a persistent illusion manufactured out of the spectator’s
mind or organ. This reduces the literal reality of things to a perspectival
reality. In this school of thought, the reality we experience is a matter of
perspective. In here, the perceived reality is the outcome of our subjective
view-point of a world which is starkly abstract by itself. Everything we observe or
experience appears the way it appears because this is how the true underlying
reality would look like when seen from our position and when experienced using
our organs. So, the perceived reality is, at best, a distorted, localized,
biased reflection of the reality as it exists.
This puzzle of subjective and objective reality does not
end here, but permeates to even more fundamental level. The subjectivity
extends to phenomena which were, for centuries, thought to be objective and
observer independent. This revolution occurred when Einstein, one of the most
formidable thinkers of all time, took the
last remainder of physical objectivity from the notion of space and time.
Until Einstein’s time, everybody believed that time is
an immutable property of the real world; that it flows at the same rate for
everyone. But Einstein figured out that even time is not free from the
subjectivity of an observer. He made a bold statement that as one moves at
faster speeds, time starts to slow down. Many people would have a tough time
understanding how time could slow down, but when one lets go of his biased
common sense, one could realize the serious implications of Einstein’s vision.
What this means is that as one starts moving at increasingly greater speeds,
all the processes start to slow, down to the atomic level. For example, a
person moving at 0.9c would appear to speak slowly, scratch his head slowly and
age slowly, relative to a person who is, say, at rest. So, now everybody have
their own private time, their own private clocks, with reference to which to
they see their worlds. We have come to call this slowing down of time “time
dilation”.
There is another astounding effect of Einstein’s
relativity: “length contraction”. When an observer travels at higher speeds,
the world he sees appears contracted or shortened. And this contraction of his
world happens from everywhere i.e. the relative dimensions are all
proportionately shortened. I can’t say
how Einstein must have felt after these realizations but I surely felt a
strangely mysterious feeling after fully understanding it.
So, back in 1905, what Einstein did was that he removed
the age-old objective stamp from our feeling of time and space. The time we see
passing through our lives and the space we feel surrounding us is all relative
and our own subjective view-point. To make the point clearer, I can give another
example. Imagine there are creatures which always travel at 0.99 times speed of
light and these creatures have evolved just like we have. How would the world
look like from their point of view? When we do mathematics, we find that if we
stationary beings feel one hr has elapsed, they would feel that only 8.5
minutes have elapsed. Their notion of space would be shrunken by 50 times i.e.
everything we see of a particular size, they would always see it shrunken by 50
times.
An obvious corollary of relativity is that if you don't
move in space, you move in time and vice versa. Imagine if there are
creatures which always traveled at speed of light, they would not move in time.
They would feel that time is stationary and space is flowing through them as if
they have no control over it. Thinking carefully, don't we too feel the same
way but order reversed for space and time? Since we are on the mass-dominant
side of mass-energy spectrum, we hardly move in space and that's why we feel
space is stationary and is all there, but for us, time moves through our lives
as if we have no control over it. Isn't the reality the way we look at it?
Thus, we return to the point we started from: The reality we perceive implacably
depends on our position and is no more universally absolute. The world is only
a perspective.
But something is amiss here. In the example of grass, there
was an underlying objective reality that the grass is made of sub-atomic
particles and we found it green because we saw it from our specific position,
both literally and figuratively. But in the case of space time, what is the
underlying reality? Whose time is correct? Whose version of space is real? Of
course, no observer gets precedence over other and hence no version of space or
time can win.
Take a simple example. A spaceship takes a flight from
Earth and lands on Moon after a time. Two observers, one standing on Earth and
the other in spaceship itself, observe this phenomenon. They don’t agree on the
time elapsed between take-off and landing and the distance travelled by the
spaceship, owing to relativity. But they both must agree on the gap between the
events in four-dimensional space-time. This gives rise to the idea that space
and time are not separate and hence two observers don’t agree separately on the
space and time, but must agree on space-time. Hence, the underlying reality is
space-time and not space and time. This reality is objective and when viewed by
differently-positioned observers leads to the drastically different views of
their worlds.
This reminds me of an important point that not only the
reality we see is a matter of perspective but also this perspective is narrow
and limited. For example, if I hold a pen in my hand, can I see the pen fully? No
matter which angle I look the pen from, I always see a partial view of it. The
reason being that with our eyes, we project a 2-dimensional image on retina of
an object which is actually 3-dimensional. The reality of pen is 3-dimensional
but we see only a 2-dimensional projection of it. That’s why we can never see
it fully. And the same goes for the reality out there. The world, according to
Einstein, is a 4-dimensional space-time and we see events unfolding in 3
spatial dimensions (again, owing to the way we evolved). That’s why we don’t
see an objective space and an objective time. That is why we see the planetary
paths curved because even if they move in a straight line in the 4-dimensional
space-time, their projection on 3-dimensional space appears curved. The conclusion
is loud and clear: The reality exists objectively and since we see it from our narrow
and specific perspectives, our perceived reality becomes subjective and
distorted picture of true reality.
But just when there seemed to be an apparent consensus
over an objective reality and its distortion by our subjective observation, a
revolution in science called Quantum Mechanics shattered all the widely held
intuitive notions about an objective reality. It destroyed the possibility of
knowing what is really going on and even rendered the question of an objective
reality meaningless.
There is a long list of counter-intuitive phenomena in
quantum mechanics, but if there is one experiment which alone sums up almost
all the quantum mystery, it would be the infamous Double Slit Experiment. When
we fire electrons through two slits, we obtain an interference pattern
indicating that electrons traveled through space as wave. But when it
arrives at its destination, it gives up its energy as tiny particles. So, in
reality, is the electron a particle or a wave? According to intuitive notion of
objective reality, the electron must be in some form (an objective form of
existence, known to the universe) and it is this form which we sometimes see as
a wave and sometimes as a particle. This idea was held by Einstein all his life
and is called Hidden variable theory. But experiments in last century have
proved that these speculations are false.
This brings us to a depressing conclusion that behind
our observations, the electron could be anything.
There is a fundamental uncertainty about the electron’s reality and even the
universe or the particle itself has no idea about it. This is summed up in the
famous uncertainty principle which rules out the possibility of knowing both
the exact position (wave behavior) and exact momentum (particle behavior)
together. The important point is that this uncertainty is not to us humans
alone, but to the universe itself. As Sir Arthur Eddington says that a
physical object has an ontologically undetermined component that is not
due to the epistemological limitations of physicists' understanding.
"The Uncertainty Principle, then, would not necessarily be due
to hidden variables but to an in-determinism in nature
itself."
In the context of Schrodinger’s Cat example,
as long as the box is close, we don't and can't know whether the cat is alive or dead. It is only when we open the box, we find it either alive or dead. Similarly,
it is only when we observe the universe, we create the reality. When we observe
the sub atomic particles (or waves), we collapse its wave-function and see it
as particle or wave. Behind observations, what it actually was, is fundamentally unknowable.
For a long time in my life, I kept thinking that may be
one day, we humans could read God's mind. But how could we read God's mind if
He himself is not sure anymore? Quantum mechanics, to me, has seriously
undermined that quest and has even changed the goal of Physics. It tells
us that we can understand the world only when we observe it because "the
moon might not be there when you don't look at it."
Werner Heisenberg once said:
"... It is possible to ask whether there is still
concealed behind the statistical universe of perception a 'true' universe in
which the law of causality (=determinism) would be valid. But such speculations
seem to us to be without value and meaningless, for physics must confine itself
to the description of the relationships between perceptions."
We should, therefore,
refrain from asking questions like “Is an electron a wave or a particle?” We
should talk only about the observed behavior. So, a meaningful question would be
“What is an electron observed to be when it passes through slits?” The answer
would be “it acts as waves.” Also, “What is an electron observed to be when it
interacts with the screen?” The answer would be “as particle”. What the
electron really is behind the observations is a meaningless question. We can’t
and should not ask questions about the reality outside of the context of it
being observed.
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So, what is our opinion about the point which we started
from? Is there an objective reality? Do we see the reality subjectively? From
above discussions, we can conclude that an objective reality does not exist.
The world as it exists is actually a ridiculously huge wave-function where
everything from electrons to cars to humans plays the game of indeterminism or
the game of probability. The behavior is dominant in subatomic world because
they are very light in mass and hence their wavelengths are appreciable, which
is why we can only speculate about a range of possibilities in this world
rather than a single deterministic possibility. But we are little fortunate in
the real world. Here, the objects have more masses and hence their wavelengths
are negligibly small. Hence, the uncertainties are too small to be noticed. And
the world seems sensibly deterministic for our purposes.
I believe that quantum theory describes the world most
accurately. In our real world, everything is blurred. There are no exact
positions, no exact momentum, not even the law of causality. An electron can,
indeed, be at two places at once. Everything falls under the realm of
possibility because the world itself is chaotic and messy. However, at our
level, we see the world so organized where it’s is possible to predict future,
where law of causality holds true and where there is no spooky action at a
distance. This happens because of two reasons (1) we deal with heavier masses
and hence uncertainty is too small to be noticed. It’s like saying we can
predict a baseball’s position to 10 decimals but not to infinite number of
decimals. But even those 10 decimals seem more than accurate and we perceive it
as determinism. (2) We only see a probabilistically averaged-out behavior. For
example, an electron can really literally go through a wall. But a baseball can
never. This is because the probability of a trillion electrons together passing
through the wall at the same time is very less. Hence we never see objects
disappearing through the walls. In the same way, entanglement, a quantum
phenomenon, never happens in real world. This is because it is
probabilistically very improbable for a trillion particles to all suddenly affect
the other trillion particles at a distance.
Thus, we only see our world as we see it because we see
from a specific position. If there were evolved creatures of dimensions of Plank's length, they would indeed
find their reality whole lot stranger than ours. Since we have evolved for
millennia under these circumstances, we have come to believe them as a default
view of the world. That’s why, if a cause does not come before an outcome, we
are shocked. That’s why, if we see absurdly random and schizophrenic behavior
of particles, we find it strange. That’s why when an electron moves through a
wall, we find it repulsive. The reality is not like that. It’s absurdly random,
confused and disorderly. There is no rule and no certainty. This reminds me of a
dialogue of Dark Knight: “The only sensible way to live in this world is without rules”.
God does seem to abide by this rule and this rule alone, no matter how repeatedly and persistently our cognition tries to convince us otherwise.
