Arguments
for the Existence of God
Philosophical
arguments for the existence of God have been propounded in the West since the
time of Plato, and have been central to the ‘natural theology’
which has, in large parts of the Christian world, provided the accepted
preamble to ‘revealed theology’.
In
Catholic thought the most prevalent philosophical argument for the existence
of God has been the cosmological
argument, moving from the contingent, caused or dependent character of
the world to God as its non-contingent source. In one form (Aquinas’ First
Way) this is an inference from the fact of change to an original initiator of
change. The illustration has been used of a line of railway trucks in motion.
The immediate explanation of the movement of a given truck is that it is
being pulled by the truck in front; and that by the one in front of it, and so
on. But even if we multiply the number of trucks to infinity, in a beginningless
and endless series, we shall still not have found the ultimate explanation of
the movement of any of them. In order to do this we have to postulate
something [namely the engine] which
is not merely one more truck but which has within itself the power to move
without requiring something else to act upon it. Likewise a changing universe,
even if it should be beginningless and endless, is ultimately explicable only
by reference to an unchanged originator of change.
Aquinas’
Third Way hinges upon the task of rendering intelligible the existence of
contingent things. Everything to which we can point is dependent for its
existence and its character upon factors beyond itself. It could not exist but
for various prior conditions, and its presence can only be explained by
reference to those preconditions. For example, the pen that I am now holding
is contingent upon the past activity of its manufacturer and the existence of
the necessary raw materials. But these prior factors are also themselves
contingent entities or circumstances, and likewise point beyond themselves for
their explanation. Thus the search for an ultimate explanation has launched
upon a regress. And either this regress is endless or it must terminate in a
non-contingent, i.e. self-explanatory or necessary, reality, which is God.
But
could a self-existent creator provide an ultimate explanation of contingent
things? Might not the universe itself, as a beginningless and endless changing
network of contingent events, be regarded as ultimate? The answer is that
the idea of God is the idea of a more ultimate reality than the universe; for
God is defined as the uncreated creator of everything that exists other than
himself. Thus the universe is, in principle, susceptible of explanation by
reference to God, but not vice versa.
It
would seem, then, that if the universe is ultimately to be explained, rather
than just accepted as ‘brute fact’, that explanation will have to be in
terms of a self-existent creator. Thus the cosmological argument presents the
dilemma: either the universe is divinely created or it is an ultimately
inexplicable given fact. But the argument does not compel us to choose one of
these alternatives rather than the other.
Among
Protestants the most favoured of the theistic arguments has been the design or teleological argument, which moves from the orderly and
apparently designed character of the world to a divine designer.
The
physical universe is not a chaos of random events but a system functioning in
accordance with universal regularities or ‘laws’. It is in fact an
efficiently functioning mechanism, in this respect comparable with a complex
human artefact - such as a clock,
which was the most obvious example available in the eighteenth century, when
the design argument was at the height of its popularity. William Paley (Natural
Theology, 1802) pointed out that if we find a watch on waste ground we
are not tempted to think that it was formed by the random effects of natural
causes. Its complex internal organization and its precise aptness for
indicating the time require us to infer an intelligent maker. And this would
be true even if we had never encountered a watch before and knew nothing of
its manufacture. Consider then, for example, the eye. With its lens focussing
light onto a photo-sensitive area, is it not as manifestly designed for seeing
as is a telescope? Or again, consider the ozone gas layer in the upper
atmosphere which surrounds our planet, filtering the radiations which fall
upon the earth’s surface. If it was appreciably thicker than it is, it
would absorb radiations that are necessary to life; and if appreciably thinner
it would let
through radiations fatal to life. Thus it is just the right thickness to
sustain earthly life. Is not this an evidence of deliberate arrangement?
This
eighteenth-century form of the argument was powerfully criticized by David
Hume (Dialogues concerning Natural Religion,
1779). Amongst other things, he pointed out that any order of nature, in
order to persist, must involve living creatures being adequately adapted to
their environments. The important question is how this order and adaptedness
have come about. Hume propounded a basic naturalistic hypothesis in which
the universe consists of a vast number of particles moving about at random.
If there is any possible arrangement of them which will constitute a
self-sustaining order, sooner or later, in unlimited time, they will fall
into that order. Perhaps we are now in such a (permanent or temporary) phase
of order, in which the universe has an appearance of design but which has
nevertheless come about without the intervention of any designer.
The
general theory that apparent design has been produced by the operation of
natural forces was strikingly confirmed in the nineteenth century by
Darwin’s theory of the evolution of the forms of life. The innumerable
instances of the efficient adaptation of organisms to their environment are
results of a process of natural selection whereby, given small random
mutations in the genetic process, features which have positive value to the
species tend to be preserved and built into the genetic stream, whilst those
with negative value tend to be eliminated in the struggle to survive. Thus
species develop over long periods of time towards more perfect adaptation to
their environment, and also in response to changes in that environment. Again,
applying this general principle to the ozone gas layer, the situation is not
that humanity and the other forms of life were in place first, and God then
added this layer for their protection, but the other way round: the ozone
gas layer was there first and only those forms of life have developed that can
emerge and survive within the kinds and levels of radiation that it lets
through.
Various
attempts have been made in the twentieth century to reformulate the design
argument. Some stress the remarkable fact that the universe exhibits a
character which
is
amenable to investigation and comprehension by the human mind. Does not the
structure of the universe, then, reflect an Intelligence analogous to our own?
It is replied that the human brain has been formed as part of the evolving
universe, and is therefore naturally adapted to analyse and understand its
environment. Other recent forms of design argument seek to demonstrate the
improbability that life could have come about on the earth’s surface purely
by chance. Thus protein, for example, is an essential constituent of living
organisms. An astronomically high improbability has been calculated for the
formation of a single protein molecule by the chance coming together of its
constituents in the right proportions and pattern. Given the volume of
substance available on the earth one can further calculate the order of time
that would be required for such a chance event to occur, and this turns out to
be many times greater than the age of the earth. Therefore, it is argued, some
anti-chance factor (namely God) must be at work. Against this it is argued
that whilst the improbability of a protein molecule being instantaneously
formed out of a random distribution of atoms is indeed immense, this immensity
is dissipated when we see the complex protein molecule as the end-product of a
long evolutionary process in which later stages of chemical synthesis have
built upon earlier ones.
In
one of its forms the moral argument can
be seen as a component within a comprehensive design argument. The universe
has produced ethical animals. Must there not then be a transcendent moral
Source or Ground of our moral nature? In another form of the argument it is
claimed that the existence of God is a necessary presupposition of the
absolute claim upon us which we find moral obligations to have. When I ought to do something this ‘ought’ is unconditional and does
not depend upon my own desires or preferences. But its absolute and
unconditional character cannot arise from any merely human or natural source.
It must derive from an absolute source of value, which we may equate with God.
Against
this position, however, it has been argued that morality can be seen as a
human device, required by the exigencies of communal life. The human animal
is gregarious, and communal living is impossible without
the
development of rules, implying general principles and supported by sanctions.
These rules are taught in the socialization of each new individual and become
internalized as conscience; and the idea of God is used to support this
moral consensus. But all this may happen, it is claimed, without there having
to be a transcendent divine being.
The
most philosophically subtle and interesting of the theistic arguments is the ontological*
argument, first clearly formulated by St Anselm.
Anselm
defines God as ‘that than which no greater (or more perfect) can be conceived’.
The fact that we can conceive of such an unsurpassably perfect being means
that it at least exists as a thought in our minds. The question is whether it
also exists as a reality outside our minds. Anselm argues that it must. If it
exists only in the mind, it is not that than which no more perfect can be
conceived; for we could then conceive of something more perfect, namely that
same being existing in reality. So long as we think of the unsurpassably
perfect being as existing only in the mind, we are not yet thinking of the
unsurpassably perfect being. In order to be unsurpassably perfect, such a
being must exist not only in the mind but also in reality. Thus when we
understand what God uniquely is, we find it impossible to think of him as not
existing.
Anselm
adds that, as the unsurpassably perfect being, God not only exists but exists
necessarily — i.e. exists in such a
way that he cannot be thought not to exist. This mode of existence is
self-existence or aseity. That which
is defined as existing eternally, and without dependence upon anything other
than itself~ cannot be thought of as not existing. As Anselm says, ‘that
alone cannot be conceived not to be in which conceiving discovers neither
beginning nor end nor combination of parts, and which it finds existing always
and everywhere in its totality’ (Responsio,
4). But it is more perfect to exist necessarily than to exist
contingently; so that the unsurpassably perfect being must exist necessarily
— and therefore undoubtedly exists. This is the ‘second’ form of the
argument, identified and defended by a number of recent writers.
The
ontological argument has been the subject of an immense and still continuing
discussion since its revival by Descartes in
the
sixteenth century. A central criticism, formulated by Immanuel Kant, is that
the argument presupposes an understanding of ‘existence’ as a predicate
which something may have or fail to have and possession of which makes it more
perfect than it would be without it. Hence the most perfect conceivable
being must have this attribute of existence. But it is claimed by the critics
that the function of ‘exists’ is not to add another element to the concept
of a kind of thing, but to assert that that concept is instantiated. Thus,
for example, ‘horses exist’ does not mean that as well as having such
attributes as four-footedness, horses also have the attribute of existence. It
means that the concept ‘horse’ has instances. And whether a concept has
instances cannot be settled by the content of the concept, but only by some
kind of observation of the universe. This empiricist analysis means that
having defined God as omnipotent, omniscient, eternal, etc., to say that God
exists is to say that this concept or definition is instantiated —
that there is a reality corresponding to it. And even if we put existence,
or even necessary existence, into the definition — defining God as an
eternally existing omnipotent, omniscient, etc. being
—
this does not settle the further
question whether this enlarged concept answers to any reality. We can never
guarantee God’s existence by defining him as existing. Thus despite its
subtlety and perennial fascination the argument seems finally to fail.
If,
as seems to be the case, God’s existence cannot be philosophically proved,
it does not necessarily follow that there is no God. It may be that, in W. H.
Auden’s words,
All
proofs or disproofs that we tender of His existence are returned
Unopened
to the sender.
William
Craig, The Cosmological Argument from
Plato to Leibniz, 1980; Charles Hartshorne, Anselm’s
Discovery, 1965; John Hick, Arguments
for the Existence of God, 1970; John Hick and Arthur McGill (eds), The
Many-Faced Argument, 1968; Thomas McPherson, The
Argument from Design, 1972; Wallace I. Matson, The
Existence of God, 1965: H. P. Owen, The
Moral Argument for Christian Theism, 1965; William Rowe, The
Cosmological Argument, 1975; Richard Swinburne, The
Existence of God,