30 October 2008
In its October 2rd 2008 issue, the National Post ran an article that covered the work of Sir Roger Penrose on the origins of the universe. (“Big Bounce versus Big Bang, by Joseph Brean) The two major theories on the origin of the universe were the “Big Bang” theory and the “Pulsating Universe” theory (or “Big Bounce”), and Sir Roger subscribed to the latter.
Both theories are alike in that they hold that the universe we know today began as a singularity; that is, a single point which held all the matter/energy of the universe. They differ in the ultimate fate of the universe: the pulsating theory holding that the universe will ultimately contract back into a singularity only to explode again; while the big bang theory is ambiguous as to whether the universe will continue to expand forever, or contract as the pulsating universe theory holds.
What was not discussed were the philosophical problems which both these theories have. These problems are important because both the Big Bang and Pulsating Universe theories are as much about philosophy as they are about physics. Both theories, in their own way, accept self-contradictory propositions in order to evade addressing what might be called “the God problem.”
The fundamental problem of both theories is that what they propose the universe began as - a singularity - makes it impossible for the universe we know today to exist. Laymen, and physicists, should not ignore the fact that physics bases its principle theories of the origin of the universe on a set of propositions that are self-contradictory.
A singularity – a point – is indivisible and without volume. If it had any size at all, even the size of the nucleus of an atom, a point would be infinitely divisible, as any segment of a line is infinitely divisible. But a point is indivisible, and therefore without parts, for if it had parts, it would be divisible into those parts.
With a point, there is no up or down, no left or right, and no inwards or outwards. If there were an inner and an outer to a point, then the point would be divisible into an inner and an outer, and a point is indivisible. Hence, there is no in and out for a point.
Both theories propose that the universe began its expansion in a direction that did not exist and was meaningless at that moment. Both theories require the universe to have done something that was physically impossible: move in an outwards direction at a time when “outwards” did not exist. For an “outwards” to have existed, the universe would have had to have a finite, that is, a non-zero, volume: a contradiction to the proposition that the universe began as a singularity. This is the first contradiction.
The second problem concerns motion. The universe today is full of motion: galaxies, stars, planets, and molecules are all in motion. But some things are at rest: the rock on the beach, for example. Common experience, and Newton
The universe as a singularity could not be in motion. Having no parts, there could be nothing internal moving that could initiate expansion. Spontaneous nuclear fission is sometimes offered as the exception to the rule that dead matter cannot self-initiate motion. Yet even within an atomic nucleus there is motion: protons, neutrons, and sub-nuclear particles do not remain in a state of rest with respect to each other. But in a singularity, there are no parts and no internal motion, not even rotation.
So, what started motion? Neither theory offers an explanation; only that it had to have happened, somehow.
The ancient Greek philosophers offered a theory that at the beginning of the universe all things were together and One. Aristotle was familiar with it, and pointed out the problems inherent in the belief, which are not solved by either of the modern theories of physics.
To the problem of the origin of motion, Aristotle offered the theory of the Prime Mover, the Uncaused Cause, which is seen today as the beginnings of the philosophical proof of the existence of God. Similar to the thrower who skips the stone across the water, a Prime Mover, an Uncaused Cause, which exists independent of the universe, had to be the initiator of the expansion of the universe, and be the origin of motion.
Aristotle was convinced of the existence of a Prime Mover not because of any religious beliefs, but because of his understanding of time and of the infinite. There had to be a beginning to the sequence of events that led to the present time. If there were no beginning because motion and the universe always had been, then, given the facts of the infinite, it would impossible to reach the present moment through an infinity of the past. And since there had to be a beginning, there had to be a beginner of motion and a beginning cause in the chain of causation that leads from the beginning to today because the dead matter of the universe cannot cause itself to move out of a state of rest.
The idea that the universe began as a singularity is something of a dodge by modern physics. If the universe began, not as a singularity, but as a thing of non-zero size, the size of a basketball or the size of the moon, the question would arise: how did this basketball, this moon-sized thing, come into being in the first place? What caused its existence? These “God-questions” are inconvenient to modern scientists for they are impossible to answer within the disciplines of science. Somehow, starting the universe as exploding out of nothing seems satisfying enough to some to avoid having to confront the nature of a finite sized, pre-expansion universe.
The pulsating universe theory is also something of a dodge. “Exploding out of nothing” has obvious philosophical problems that even a physicist cannot easily ignore. By proposing that the universe always was and always will be, the pulsating universe theory evades having to ask how matter and energy came to be in the first place, because they had no origin: they always were.
It is here that the subtle difference in the handling of time between the two theories occurs. With Big Bang, it is unclear whether time exists prior to expansion. With Pulsating Universe, time must exist independently of the universe.
The Pulsating Universe theory falls afoul of science since it is inherently non-falsifiable. There is no way to tell if a universe existed prior to our own, no more so than it is possible to tell what the shape of the bronze was prior to it being melted and cast into the form of a statue. Having to pass through the condition of a singularity wipes away all trace of the prior character and even existence of the previous universe, as well as cause the extinction of all motion. [This could represent a violation of the Law of Conservation of Angular Momentum of the present universe, though we cannot presume to know the laws of physics of a prior universe.] Thus, insofar as science goes, Pulsating Universe theory is not science but a philosophical treatment of a weakness of the Big Bang theory: namely that of the cause of the origin of the singularity. It also suffers from the problem concerning infinite time: the present cannot be reached through an infinity of the past.
One difference, that of whether this universe will expand forever or stop expanding and contract again, is not verifiable, and therefore places the question beyond the realm of science. In the first place, the species of man, given the realities of evolution and of space travel, is unlikely to exist long enough to verify whether expansion will stop or not. And given the mental gymnastics and self-contradiction needed to justify so-called “dark matter,” “dark energy,” and other dodges to “the God problem,” science may never be able to resolve definitively which of the two theories it prefers.
If one accepts a Big Bang with ultimate contraction, there is no principled reason to deny an infinite repetition of the phenomenon, with all the associated problems of reaching the present through an infinity of the past. And if one holds that this universe is a one-off exception, then one is confronted with the major philosophical and scientific problem of “how come?”
Scientific disciplines have philosophical problems that lie at their origins. The origin of the universe is the beginning of physics, and the origin of life is the beginning of biology. Both these disciplines have issues with “the God problem” because they have within themselves no satisfactory explanation for the origin of their respective disciplines. The Pulsating Universe theory of Sir Roger Penrose steps outside science in order to create a dodge for the fundamental problem of what, in the first place, caused the origin of the universe we know today, and neglects the problem of how one reaches the present through an infinity of the past.
Aristotle noted in his Metaphysics that sciences begin by assuming the existence of their sphere of knowledge, and only philosophy addresses the problem of what-is. The origin of life and the origin of the universe are problems as much philosophical as they are scientific, and when Sir Roger Penrose speaks of the origin of the universe he speaks more as a philosopher than as a scientist. As a committed scientist, he has a philosophical commitment against admitting to “the God problem.”
- XXX –
No comments:
Post a Comment