Source of "The Unification of Art" is
title:A BRIEF HISTORY OF TIME
by STEPHEN W.HAWKING
The Unification of Physics
As was explained in the first chapter, it would be very
difficult to construct a complete unified theory of everything
in the universe all at one go. So instead we have made
progress by finding partial theories that describe a limited
range of happenings and by neglecting other effects or ap-
proximating them by certain numbers (Chemistry, for exam-
ple, allows us to calculate the interactions of atoms, without
knowing the internal structure of an atom's nucleus.) Ulti-
mately however, one would hope to find a complete, consis-
tent, unified theory that would include all these partial theories
as approximations, and that did not need to be adjusted to fit
the facts by picking the values of certain arbitrary numbers in
the theory. The quest for such a theory is known as "the
unification of physics." Einstein spent most of his later years
unsuccessfully searching for a unified theory, but the time
was not ripe:
As I shall describe, the prospects for finding such a theory
seem to be much better now because we know so much more
about the universe.
Rather similar, seemingly absurd infinities occur in the
other partial theories, but in all these cases the infinities can
be cancelled out by a process called renormalization. This
involves cancelling the infinities by introducing other infini-
ties. Although his technique is rather dubious mathemati-
cally, it does seem to work in practice, and has been used
with these theories to make predictions that agree with obser-
vations to an extraordinary degree of accuracy. Renormalization,
however, does have a serious drawback from the point of
view of trying to find a complete theory, because it means
that the actual values of the masses and the strengths of the
forces cannot be predicted from the theory, but have to be
chosen to fit the observations.
But can there really be such a unified theory? Or are we
perhaps just chasing a mirage? There seems to be three
1) There really is a complete unified theory, which we will
someday discover if we are smart enough.
2) There is no ultimate theory of the universe, just an
infinite sequence of theories that describe the universe
more and more accurately.
3) There is no theory of the universe; events cannot
be predicted beyond a certain extent but occur in a
random and arbitrary manner.
Some would argue for the third possibility on the grounds
that if there were a complete set of laws, that would infringe
God's freedom to change his mind and intervene in the
world. It's a bit like the old paradox: Can God make a stone
so heavy that he can't lift it? But the idea that God might
want to change his mind is an example of the fallacy, pointed
out by St. Augustine, of imagining God as a being existing in
time: time is a property only of the universe that God created.
Presumably, he knew what he intended when he set it up!
With the advent of quantum mechanics, we have come to
recognize that events cannot be predicted with complete accu-
racy but that there is always a degree of uncertainty. If one
likes, one could ascribe this randomness to the intervention of
God, but it would be a very strange kind of intervention:
there is no evidence that it is directed toward any purpose.
Indeed, if it were, it would by definition not be random. In
modern times, we have effectively removed the third possibil-
ity above by redefining the goal of science: our aim is to
formulate a set of laws that enables us to predict events only
up to the limit set by the uncertainty principle.
The second possibility, that there is an infinite sequence of
more and more refined theories, is in agreement with all our
experience so far. On many occasions we have increased the
sensitivity of our measurements or made a new class of
observations, only to discover new phenomena that were not
predicted by the existing theory, and to account for these we
have had to develop a more advanced theory.
In effect, we have redefined the task of science to be the
discovery of laws that will enable us to predict events up to
the limits set by the uncertainty principle. The question re-
mains, however: How or why were the laws and the initial
state of the universe chosen?
Up to now, most scientists have been too occupied with the
development of new theories that describe 'what' the universe
is to ask the question 'why'. On the other hand, the people
whose business it is to ask why, the philosophers, have not
been able to keep up with the advance of art. In the eighteenth
century, philosophers considered the whole of human knowledge,
including science, to be their field and discussed questions
such as: Did the universe have a beginning? However, in the
nineteenth and twentieth centuries, the universe became too
abstract for philosophers , or anyone else expect a few specialists.
Philosophers reduced the scope of their inquiries so much the
Wittgenstein, the most famous philosopher of this century, said
"The sole remaining task for philosophy is the analysis of
language." What a comedown from the great tradition of philosophy
from Aristotle to Kant!
However, if we do discover a complete unified theory, it should in
time be understandable in broad principle by every one, not just a few
meta-artists. Then we shall all, philosophers, scientists, and just
ordinary people, be able to take part in the discussion of the question
of why it is that we and the universe exist. If we find the answer to
that, it would be the ultimate triumph of human reason-for then we would
know the mind of God.