**THE CHRISTIAN FAITH AND THE NEW PHYSICS**

Bernard Tan

National University of Singapore

__Ancient physics__

Before the Rennaisance,
science, and physics in particular, functioned largely in harmony with the
established state and with organised religion.
In ancient Greece, China and India, astronomical observations of heavenly
bodies were sanctioned by the state for the useful functions they could
provide, such as the making of calendars and the marking of seasons for
agricultural purposes, as well as for navigation at sea.

These observations also
supported official religious practices, and in many cases provided a framework
for the legitimacy of the ruling elite.
The ability to predict significant heavenly events, such as solar
eclipses, helped rulers to keep the populace in awe and to convince them that
their rulers had some kind of heavenly mandate. In many states, rulers were assigned a degree of divinity which
had to be confirmed by their ability to forecast these events. Hence the official state astronomers gained
an importance in the state apparatus which enabled observational physics to
flourish.

__Models of the universe__

The need to explain the
movements of heavenly bodies gave rise to many models of the universe and the
solar system. In Greek physics, the
Ptolemaic system envisioned the planets, the Sun, and the stars as moving in
circular orbits around the earth.
However, this model could not account for the actual observed paths
which these bodies were seen to take, so it had to be refined with a system of
epicycles which became more and more complicated as time went by.

Eventually, the Copernican
model of the solar system was proposed and found to provide a more
scientifically satisfying picture of reality.
This model requires the earth to revolve around the Sun and hence came
into direct collision with the accepted religious tenet of the Church that the
earth and mankind, being the pinnacle of God’s creation, had to occupy the
centre of the universe.

Nevertheless, the Copernican
model, through its simplicity compared with the complex Ptolemaic cycles and
epicycles, became the accepted scientific model of the solar system. Kepler further refined the Copernican model
and published his famous three Laws of planetary motion. Galileo provided further evidence for the
heliocentric nature of the solar system and also propounded the Law of Inertia,
i.e. objects which are in motion tend to stay in motion. Galileo, of course, was to come into direct
collision with the Church which forced him to publicly recant the Copernican
theory.

__Newton and the
deterministic universe__

Isaac Newton was therefore
able to build on these foundations and
propound a theory of gravity which was able to account for the workings
of Kepler’s three laws. In addition,
Newton’s three Laws of Motion have become the basis for all of classical
physics, and are of course still valid today in the non-quantum world.

Newton’s Laws thus providid
the basis for a universe in which, gven the required intitial conditions, one
could predict the future state of any physical system, and indeed of the entire
universe. This led to a model of the
entire universe as a deterministic system which ran like a well-ordered
clockwork machine, whose settings were already predetermined and whose future
could be predicted, given that the initial parameters were known.

The consequence of this for
religious thought was profound. In
particular, those who believed in a universe in which everything had been
predestined found support for their views in scientific determinism. Naturally, those in favour of a universe in
which free will still had meaning found determinism to be a major stumbling
block.

__Statistical physics and
the Laws of Thermodynamics__

The notion of cause and
effect, which must have profound religious consequences, was also bound up with
the clockwork-like determinism of a Newtonian universe. Strictly speaking, Newtonian physics was not
sensitive to time direction. All the
equations of classical physics would work even if time were reversed. For example, if a movie of a bouncing ball
were played in reverse, it should still appear to obey the laws of classical
physics.

However, it is apparent that
there are many phenomena in nature which are not reversible in time. For example, a movie of a bowl which
shatters when dropped to the ground would not seem to be natural. Such phenomena, it appears, are intimately
connected to the notion of order. There
seems to be a tendency for ordered arrangements to be come disordered in the
natural scheme of things. A pack of cards,
if arranged in order, will become disordered when shuffled. Hence there are natural phenonema which
favour one direction of time but not the reverse direction.

The discipline of statistical
physics, which arose from the study of thermodynamics or the physics of heat,
deals precisely with such phenomena.
Statistical physics deals with the behaviour of large numbers of
objects, whose behaviour appears to be random.
For example, individual molecules is a gas move about and collide with
each other randomly, but taken as a whole, we can predict their behaviour very
accurately.

The three Laws of
Thermodynamics provide the basis for our understanding of the behaviour of
physical systems composed of large numbers of randomly behaving objects. One of the key concepts of statistical
physics is entropy, which roughly speaking denotes the degree of disorder of a
system. A pack of cards which is
properly arranged in order has low entropy, while a pack which has been
shuffled thoroughly has high entropy.
The natural world tends towards an increase of entropy, and in fact the
universe should tend towards a final state when all order has been lost, and
“Heat Death” is the result.

These concepts have religious
resonances in several ways. The notion
of increasing entropy implies that the universe proceeds in a fixed direction
of time, towards increasing disorder.
This also implies that the initial state of the universe was one of
perfect order, and is continuously being degraded. Hence entropy appears, to some people, to support the notion of
divine creation at the beginning which is being degraded as time
progresses. Conversely, evolution,
which implies the increasing of order with time appears to contradict the Third
Law of Thermodynamics, i.e. that entropy is increasing all the time. However, in actual fact, entropy cannot be
used to support opposition to evolution, because one has to take the entropy in
a system (in this case the solar system or the universe), as a whole.

The classical model of the
universe was severely undermined at the beginning of this century by two major
developments in Physics - Relativity and Quantum Theory. These have so profoundly changed the face of
physics that we count the genesis of these two Theories as the birth of Modern
Physics.

__Relativity__

The name we associate most
with the Theory of Relativity is Albert Einstein. The theory is based on a solid observational fact - that the
velocity of the speed of light is a constant, not matter what the relative
velocities of the light source and the observer may be. Many careful observations, such as the Michelson-Morley
experiment, were made to confirm this suprising conclusion, and many
alternative theories, such as the existence of ether, were put forward to
explain it.

Hence Einstein’s Theory of
Relativity is based on solid experimental fact, and its predictions have been
confirmed by careful observation as well.
There are two branches of Relativity theory - Special Relativity and
General Relativity.

In Special Relativity,
Einstein deals with situations in which objects travel at a constant velocity
near the speed of light. Time becomes
just another dimension of space, and can be dealt with likewise. Many suprising results, such as time
dilation and the contraction of objects when seen by a stationary observer, run
totally contrary to common sense, which explains why Relativity was so
misunderstood by the general public for such a long time. Special Relativity also profoundly changes
our common sense concept of simultaneity, and hence of causuality. For example, two observers moving at
different velocities to another person may observe events happening to that
person in different order.

General Relativity theory is
even harder to understand than Special Relativity. However, one important point about it is that it extends Newton’s
work on gravitation. In General
Relativity, the effects of gravitation and acceleration are considered to be
identical, and hence gravitational force and the force due to acceleration are
equivalent to each other. In this way,
gravitational force becomes just a property of space, which is distorted when
objects with mass are present. Hence
the earth may be said to attract objects by virtue of its distorting space,
thus forcing objects into a path towards it.

__Quantum Theory__

Quantum Theory, which is the
other pillar of Modern Physics, also has profound implications for religious
thought. Like Relativity, this theory
also rose from experimental observation.
It had long been observed that so-called “Black bodies” emit a spectrum
of radiation which peaks at a certain frequency and then tails off at higher
frequencies. If light and heat are
electromagnetic waves, then classical theory predicts that at higher
frequencies, such bodies must emit even higher amounts of radiation.

This paradox was overcome
only when it was postulated (by Einstein and others) that perhaps light was not
a wave motion, but came in small packets of energy, which we now call
photons. By applying this assumption,
the problem with the explanation of Black body radiation was overcome.

However, physics now had to
face a bigger problem: how could light behave both as a wave and as particles
at the same time? It was undoubtedly
true that light behaved as a wave, as phenomena such as diffraction and
interference were intrinsic properties of light. Hence arose the paradox known as the “Wave-particle duality” in
which not only light, but every other physical object, has both the properties
of waves as well as of particles. In
everyday life, of course, objects such as human bodies are so large that their
wave-like properties are unobservable.

Quantum theory therefore
developed a whole new formalism to deal with this duality. The equations of Quantum Theory deal with
“Wave functions”, which all objects possess.
It is only at the very smallest level of physical objects that their
wave properties become apparent. One
consequence of this duality is the famous “Uncertainty Principle” of
Heisenberg, which states that the velocity and position of an object can never
be determined perfectly accurately together.

__Interpretation of Quantum
Theory__

The interpretation of the
wave function has given rise to much debate in the physics community. The standard interpretation is that the wave
function is a probability function, in
which objects keep their sharply defined particle nature, but whose positions
can only be predicted by the probability function. This seems to satisfy most people, since it implies that the
objects are still sharply defined as particles, and that we simply do not know
where they are.

However, the probability
function implies that we do not know and cannot predict the actual position or
location of the partcle, but when we actually attempt to measure its location
or momentum, we force the wave function to collapse such that the particle will
assume a definite position or momentum. (Of course, subject to the Heisenberg
Uncertainty Principle.)

However, Quantum theory seems
to imply that the wave-particle duality runs deeper than that, and that each
and every particle carries a wave property with it like a kind of ghost. The Young double-slit experiment showed
clearly that interference phenomena occur even when only single photons are
involved.

Another interesting thought
experiment is the Schrodinger’s cat experiment (named for Erwin Schrodinger,
one of the founders of Quantum Physics), whose life or death seems to depend on
the state of the wave function of a single electron which triggers off a series
of events releasing a poison gas into the container where the cat is kept. Since the wave function’s values are
indeterminate until we force it to collapse, and the cat’s life or death
depends on definite values of the wave function, is the cat alive or dead
before the wave function is forced to collapse by our observation?

Einstein himself was never comfortable with the
probability interpretation of Quantum Theory, or that the wave function implied
that there hidden variables which we could never see. As he famously said, “God does not play dice with the universe.”

A small number of physicists
have looked for alternative interpretations of Quantum Physics. David Bohm and others have propounded
alternative models which have recently attracted renewed interest in
alternatives to the probability function interpretation of Quantum Physics
(usually known as the Copenhagen interpretation, after the Danish physicist
Neils Bohr). Bohm himself has proposed a quantum model in which every particle
possesses a so-called ''pilot wave'' which can account for the particle's wave
properties.

An interesting alternative
interpretation is the so-called “Many-Worlds” model of the universe in which an
infinite number of parallel universes exist, is proposed. In the standard
Copenhagen interpretation, the wave function which represents the sum of all
possible configurations of the particle, collapses into just one configuration
when a measurement or observation is made.
In the Many Worlds theory, ALL of these outcomes will actually be
realized in parallel universes which exist alongside our own. Such a bizarre model of the universe must
surely have profound philosophical and theological implications.

__Chaos Theory__

In studying physical systems
which obey the classical laws of physics, physicists have assumed that for all
such systems, a given defined starting point would lead to predictable
outcomes. If such systems comprised large numbers of individual objects
behaving randomly and unpredictably, then they would obey the laws of
statistical physics predictably. However, it has since been discovered that
there are many systems in the real world which do not exhibit such predictable
behaviour, but also are not random systems describable by the laws of
statistics. Such systems are known as Chaotic systems, and they abound in
nature. One characteristic of such
systems, which is quite counter-intuitive, is that extremely small starting
differences can make very large differences in outcomes.

The meteorologist Edward
Lorenz discovered that the global climate system was just such a Chaotic
system. For example, a butterfly
flapping its wings could trigger off a hurricane on the other side of the
world. Such an outcome, which one would
not expect in classical physics, is a common feature of Chaotic systems. Hence in such systems, causuality may run
counter to what is common-sense, and hence have important implications for
theological ideas of predestination and free will.

Chaos theory has provided
physicists with new insights into the nature of physical systems and of nature,
which contradict previously held views about randomness and determinism. Chaos theory has also provided new ways of
looking at the universe and nature, through such topics as fractals and the
Mandelbrot set. The Mandelbrot set,
which shows that wholly unexpected and amazing results can come from very
simple mathematical assumptions, is well known through the many startlingly
beautiful patterns which it can create.

The most surprising feature
of these patterns is their ability to create complex patterns within complex
patterns, in a self-repeating way.
These patterns have properties which are so complex that they consitute
a class of objects midway between a normal line and a plane. Another amazing feature is the way in which
these patterns appear to mirror natural objects such as clouds and plants. These patterns seem to imply that there are
worlds within worlds which can constitute an infinite regress as we examine
them closer and closer, and must have resonances in theological thought about
the infinite resources of a divine creator.

__Complexity and the
holistic universe__

Chaos theory and its many
related concepts are now seen as part of an increasing interest in the Theory
of Complexity. Many of these ideas tend
towards a holistic view of the universe as a whole, such that every part of it
is somehow related and connected to every other part. The recording of images using holography is a precursor of such a
concept, for the holographic image resides in the hologram in such a way that
every part of the image is in every part of the hologram, unlike a normal
photograph.

This holistic view of the
universe, which Bohm and other physicists have strongly espoused, has major
implications for theological thought.
Such a universe may appear to provide support for a divine creator, though
many physicists still believe that divine intervention does not need to be
invoked for the universe to run as it does.
Those who hold to a pantheistic world view may also find support for
their position in such a holistic universe.

In this short talk, I have
not attempted to cover all of present day physics, for that would be an
impossible task. I have not covered,
for example, theories regarding the origins of the universe, such as the big bang
and the steady state theory, nor have I covered the latest developments in the
physics of elementary particles. There
are many exciting advacnces in these areas, such as string theory, but I must
leave that for another time.

What I have tried to do is to
give a coherent picture of the development of physical thought from earliest
times to the present, particularly with respect to the very fundamental ideas
which have had and are having such a profound impact on philosophical and
theological thinking on determinism and free will. I hope that this talk will stimulate you to examine more closely
the relationships between science and Christian theology which could benefit
both scientists and theologians.