Saturday, 14 May 2011

Chimpanzees and a free lunch

In the UK magazine New Scientist (7 May) there is an absorbing article by Michael Brooks called ‘What we’ll never know’.  This must of course be confined to areas of knowledge we can at least conceive of, otherwise we can’t even talk about them.

It makes this point via an observation from the Astronomer Royal, Lord Martin Rees, concerning chimpanzees. Chimpanzees, he says, not only do not understand quantum mechanics but they are not even aware of it. They don’t even know that they don’t know it. And similarly with us in relation to the whole realm of reality. Rees puts it this way.

‘There is no reason to believe that our brains are matched to understanding every level of reality.’

The article talks about a number of limits we are aware of: the cosmic horizon, which recedes at the speed of light; Godel’s theorem of undecidability, from which it follows that we can never build a description of reality based on mathematical models; and two limits about which there is disagreement as to whether they are limits to our knowledge – life and consciousness.

However, it emerges that some scientists are attempting to probe beyond the limits of reason by trying to ‘explain’ how the universe started. In their desperation to deny an uncaused first cause, i.e. that the universe came into existence from some source they will never be able to understand, certain cosmologists are seriously trying to propose that it created itself out of nothing – a free lunch. On p.36 the article states that

 ‘the universe could have come into existence spontaneously when its energy state momentarily flickered away from zero.’

How can a universe have any energy state at all if it does not already exist? This is claiming that some entity with an energy state of zero ‘flickered’ into existence. The entity was not nothing, but something with an energy state of zero. Nothing is a complete absence of existence, not something out of which a whole universe can emerge. (NB: it is possible for a system to have zero energy; some cosmologists maintain that the entire universe has zero energy when you balance negative against positive energy, i.e. attractive against repulsive energy.)

In the same paragraph the author invokes Heisenberg’s uncertainty principle, which states that the uncertainty in the measurement of energy multiplied by the uncertainty in the time at which it is measured is equal to a constant numerical value (known as Planck’s constant, h). A consequence of Heisenberg’s principle is that no system can have precisely zero energy. If it did its position in time would be infinitely uncertain, because its energy would be known with infinite precision, i.e. with zero uncertainty. The equation would give infinity x zero, a mathematical absurdity.

So how could the entity which preceded the universe have zero energy? In fact the article itself states that the uncertainty principle

‘shatters the notion that anything ever has exactly zero energy.’

Even if one suspends disbelief and accepts that the universe (or, if you wish, the entity which preceded it) did have an energy state before it existed, then according to Heisenberg that state could not be exactly zero.

It comes as a relief to me that things cannot just pop into existence from nowhere and at random. There is no free lunch. It certainly would not be good for science but could herald a highly unsatisfactory reality with no labyrinth of scientific laws waiting to be revealed.

So  I suggest the first cause of the universe must remain beyond the limits of scientific knowledge, just as quantum mechanics is beyond the realm of chimpanzees, and that we concentrate on trying to understand how it works.

 There is a long way to go.

Author, 2077 AD