I
have been reading with interest Stephen Hawking's book, 'A Brief
History of Time'. I was surprised to see it was first published in
1988. It seems like only yesterday when everyone was reading it,
except me. Now I have caught up, it seems oddly relevant.
Is
this because not much has happened since in the world of high-energy
physics? He seems to think that a great breakthrough might be
imminent, starring string theory. It hasn't happened, and doubters
are growing. Some of Hawking's remarks suggest an ambivalence, as
though he was never convinced.
A
pattern had been established in the quantum theory, where a new piece
of exotic maths was developed, and immediately was the key to a great
breakthrough in theoretical physics. Some may have wrongly concluded
that this was an inevitability, and so string theory would unlock
doors just like complex numbers and matrix algebra had done. It
hasn't happened. And why should it? You have to be using the right
piece of maths.
Tragically,
public understanding of science seems to be in decline, largely as a
result of the mischievous efforts of a few noisy persons. The quantum
theory, particularly the Uncertainty Principle, gave rise to a new,
more accurate and more humble understanding of what science was. You
can't measure anything about a fundamental particle without bashing
it with another one, affecting its properties. The realisation that
measurement was meaningless in the abstract, that it was impossible
to separate the observer from the observed, made people think more
clearly about what science was all about.
Hawking
neatly summarises the new understanding in the first chapter: “..a
scientific theory...is just a model of the universe, or a restricted
part of it, and a set of rules that relate quantities in the model to
observations that we make. It exists only in our minds and does not
have any other reality...it must make definite predictions about the
results of future observations.”
This
gives a realistic and rather humble view of what science is. Yet
later on he also states: “..our goal is nothing less than a
complete description of the universe we live in.”
Isn't
there a tension between these two statements? The first one reflects
a widely-held understanding (originally due to Karl Popper) of what
we really do when we do science. The second may be more peculiar to
cosmologists.
What
Hawking doesn't discuss, is what one may call the Hamlet Effect:
“Vanity, vanity, all is vanity.” Yet this impacts what actually
happens in science as much as in other walks of life, and deeply
undermines the objective view expressed in my first quotation from
Prof Hawking. People don't want approximate models of restricted
applicability, they want to understand the fundamental workings of
the universe, and the conflict between this desire and the true
understanding runs throughout the book. The history of physics is
replete with instances of people declaring it a finished subject,
even before the atomic nucleus had been discovered! Why are they
obsessed with announcing that they know everything? Ask Hamlet.
The
general public is rarely treated to a realistic view of science,
rather it is presented in an absolutist fashion, with disputes and
differences of emphasis suppressed. Hawking makes many references to
the role of God in the text of his book, often of a tentative nature,
but saying things like “this leaves little for God to do”. Yet
were he to stick strictly to his definition of science, he should
rather have remained silent on the subject of God altogether. How can
you “make definite predictions about the results of future
observations” concerning the creator of the whole universe? An
entity which necessarily would have some kind of existence outside of
space and time themselves? If God exists, his properties as a
totality are inconceivable to the human mind, almost by definition.
In order to critique a concept as a scientific theory, it needs to be
well-defined, or else it lacks the qualities of a scientific theory,
and hence falls outwith the ambit of science. It is the tragic vanity
of some scientists that they do not want to see this, almost seeming
unable to grasp the idea that many ideas are simply not a science,
and that does not mean they are wrong or inferior. It is impossible
to incorporate an idea into science unless it can be subjected to
systematic and precise observation. Sneering at other people's
unscientific notions is not a part of science, rather it is a
manifestation of the Hamlet Effect. Science consists of constructing
models and comparing the results of observations with them, and that
is all. There is neither necessity nor possibility to incorporate
everything into a scientific model.
Hawking
mentioned that a scientific model exists only in our minds.
Psychology is beginning to grasp that the human mind has certain
in-built patterns of thought, in much the same way that a computer
operating system has a limited library of system calls, and all
programs runnable on that computer are some combination of this
vocabulary. Other analogous situations include the fact that all DNA
is some combination of chains of four amino-acids; all written words
are a combination of a limited alphabet. What if the true nature of
reality cannot be adequately modelled by the limited set of routines
available to the human mind? Science would perforce remain
incomplete. Why should an evolutionary process comprised of chasing
animals about and throwing things at them give rise to a mental
process capable of understanding the fundamental laws of nature? If
we can do so, isn't that a bit of a miracle?
Will
cosmologists ever really succeed in writing an accurate history of
time? I am sceptical. I suspect there are fundamental limitations on
what can be detected from within the Solar System. Recent
improvements in space technology have revealed how tentative and
fluid our knowledge is. The public has been bombarded with
enthusiastic propaganda about 'dark matter', a new form of matter
postulated by astronomers which gives off no detectable radiation,
and does not interact with ordinary matter. A recent space-based
telescope of unprecedented sensitivity revealed that huge numbers of
dim stars exist that had previously not been suspected. A significant
proportion of the “dark matter” was instantaneously transformed
into “dim matter”. I won't be surprised if much of the rest of it
progressively goes the same way. Yet surely there can be ordinary
matter too dim for even the most sensitive detector? Astronomers
estimates of this are based on the vaguest of theories.
Similarly,
as the Voyager space probe has reached the edge of the Solar System,
it has produced surprises about the nature of the stuff that lies
between the stars.
Isn't
there a degree of vanity, never mind over-optimism, in trying to take
an inventory of the entire cosmos? Yet without this, cosmology is
impractical. Observations of such things as the cosmic background
microwave radiation will always be subjected to multi-layered
theoretical interpretation. The link between theory and the directly
observable is unusually tenuous in cosmology, especially as it is
historical rather than contemporary in character. Its deep problems
and tentative nature are rarely mentioned in popular accounts which
claim that science has somehow done away with God.
An
analogy popular with physicists considers the case of a race of
hyper-intelligent ants trapped on the inside of a football. Their
science may well conclude that the cosmos is curved, finite and has
existed only for a limited time. They may consider the possibility of
something outside of it, but will have no way of imagining what it
might be, never mind detecting it. Unless someone starts kicking the
ball.
