"No one can prove an unrestricted
negative" is the reply usually given to those who claim
that science can prove that God does not exist. An unrestricted
negative is a claim to the effect that something doesn't exist
anywhere. Since no one can exhaustively examine every place in
the universe, the reply goes, no one can conclusively establish
the non-existence of anything.
The principle that no one can prove an unrestricted negative,
however, is itself an unrestricted negative. It says, in effect,
that there are no proofs of unrestricted negatives. But, if
there are no proofs of unrestricted negatives, then no one can
prove that no one can prove an unrestricted negative. And if no
one can prove that no one can prove an unrestricted negative,
then it must be logically possible to prove an unrestricted
negative. So the claim that no one can prove a universal
negative is self-refuting-if it's true, it's false. What I
intend to show here is not only that unrestricted negatives can
be proven, but that a number of them have been proven.
Parmenides realized over 2,500 years ago that anything that
involves a logical contradiction cannot exist. We know that
there are no married bachelors, no square circles, and no
largest number because these notions are self-contradictory.
They violate the most fundamental law of logic-the law of
noncontradiction-which says that nothing can both have a
property and lack it at the same time. So one way to prove a
universal negative is to show that the notion of a thing is
inconsistent.
To prove that God does not exist, then, one only has to
demonstrate that the concept of God is inconsistent. Traditional
theism defines God as a supreme being-a being than which none
greater can be conceived, as St. Anselm would have it. We know,
however, that there is no supreme number because such a notion
involves a logical contradiction. Every number is such that the
number 1 can be added to it. If there were a supreme number, it
would be such that the number 1 can and cannot be added to it,
and that's impossible. Many believe that the notion of a supreme
being is just as incoherent as the notion of a supreme number.
Consider, for example, the claim that god is all-good and
thus both perfectly merciful and perfectly just. If he is
perfectly just, he makes sure that everyone gets exactly what's
coming to them. If he is perfectly merciful, he let's everyone
off. But he can't do both. So the notion of a supreme being may
be internally inconsistent.
This is just one of many inconsistencies that have been found
in the traditional concept of God. For a more complete review of
them, see Theodore Drange, "Incompatible-Properties
Arguments: A Survey" in Philo
(Fall/Winter 1998). Theists, of course, will claim that,
properly understood, there is no contradiction. What if they're
right? What if it's logically possible for the God of
traditional theism to exist? Does that mean that one cannot
prove that he does not exist? No, for in order to prove that
something does not exist, one need not show that it is logically
impossible. One need only show is that it is epistemically
unnecessary-that it is not required to explain anything. Science
has proven the non-existence of many things in this way, such as
phlogiston, the luminiferous ether, and the planet Vulcan.
Scientific proofs, unlike logical proofs, do not establish their
conclusions beyond any possibility of doubt. But they are proofs
nonetheless, for they establish their conclusions beyond a
reasonable doubt and that is all that is needed to justify them.
Phlogiston, the luminiferous ether, and the planet Vulcan are
theoretical entities that were postulated in order to explain
various phenomena. Phlogiston was postulated to explain heat,
the luminiferous ether was postulated to explain the propagation
of light waves through empty space, and Vulcan was postulated to
explain the perturbations in the orbit of Mercury. Science has
shown, however, that these phenomena can be explained without
invoking these entities. By demonstrating that these entities
are not needed to explain anything, science has proven that they
do not exist.
God is a theoretical entity that is postulated by theists to
explain various phenomena, such as the origin of the universe,
the design of the universe, and the origin of living things.
Modern science, however, can explain all of these phenomena
without postulating the existence of God.1
In the words of Laplace, science has no need of that hypothesis.2
By demonstrating that God is not needed to explain anything,
science has proven that there is no more reason to believe in
the existence of God than to believe in the existence of
phlogiston, the luminiferous ether, or Vulcan. This may explain
why more than 90% of the world's top scientists disbelieve or
doubt the existence of God.3
Scientists prefer natural explanations to supernatural ones,
not because of any metaphysical bias on their part, but because
natural explanations produce more understanding than
supernatural ones. As Plato realized, to say that God did it is
not to explain anything, but simply to offer an excuse for not
having an explanation.4
The goodness of an explanation is determined by how much
understanding it produces, and the amount of understanding
produced by an explanation is determined by how well it
systematizes and unifies our knowledge. The extent to which an
explanation systematizes and unifies our knowledge can be
measured by various criteria of adequacy such as simplicity (the
number of assumptions made), scope (the types of phenomena
explained), conservatism (fit with existing theory), and
fruitfulness (ability to make successful novel predictions).
Supernatural explanations are inherently inferior to natural
ones because they do not meet the criteria of adequacy as well.
For example, they are usually less simple because they assume
the existence of at least one additional type of entity. They
usually have less scope because they don't explain how the
phenomena in question are produced and thus they raise more
questions than they answer. They are usually less conservative
because they imply that certain natural laws have been violated.
And they are usually less fruitful because they don't make any
novel predictions. That is why scientists avoid them.
The realization that the traditional God of theism is not
needed to explain anything-that there is nothing for him to
do-has led a number of theologians to call for the rejection of
this notion of god. In Why Believe in God? Michael Donald
Goulder argues that the only intellectually respectable position
on the god question is atheism.5
In Why Christianity Must Change or Die, Reverend Spong,
former Episcopal Bishop of New Jersey, argues that the
traditional theistic conception of God must be replaced by one
grounded in human relationships and concerns.6
Both agree with Stephen J. Gould that religion should not be in
the business of trying to explain the world.7
What if there was no plausible natural explanation for some
phenomena? Would that justify the claim that god caused it? No,
for our inability to provide a natural explanation may simply be
due to our ignorance of the operative natural forces. Many
phenomena that were once attributed to supernatural beings such
as earthquakes, volcanoes, and disease can now be explained in
purely natural terms. As St. Augustine realized, apparent
miracles are not contrary to nature but contrary to our
knowledge of nature.8
Given the inherent inferiority of supernatural explanations
and the incompleteness of our knowledge, theists would be
justified in offering a supernatural explanation for a
phenomenon only if they could prove that it is in principle
impossible to provide a natural explanation of it. In other
words, to undermine the scientific proof for the non-existence
of god, theists have to prove an unrestricted negative, namely,
that no natural explanation of a phenomenon will be found. And
that, I believe, is an unrestricted negative that no theist will
ever be able to prove.
Notes
1. See, for example, Richard Dawkins, Climbing
Mount Improbable (New York: W.W. Norton, 1996); Stephen
Hawking, A Brief History of Time (New York: Bantam,
1998); Lee Smolin, The Life of the Cosmos (London:
Oxford, 1997).
2. When the French physicist Pierre Simon de
Laplace explained his theory of the universe to Napoleon,
Napoleon is said to have asked, "Where does God fit into
your theory?" to which Laplace replied, "I have no
need of that hypothesis."
3. E. J. Larson and L. Witham, "Leading
Scientists Still Reject God," Nature 394 (July
23, 1998).
4. Plato, Cratylus, 426 a.
5. Michael Donald Goulder, Why Believe in
God? (London: SCM Press, 1983).
6. John Shelby Spong, Why Christianity Must
Change or Die (San Francisco: Harper, 1999).
7. Stephen J. Gould, Rock of Ages: Science
and Religion in the Fullness of Life (New York: Ballantine,
1999).
8. St. Augustine, The City of God, XXI,
8.
Theodore Schick, Jr., is professor of philosophy at
Muhlenberg College. He is the co-author of How to Think About
Weird Things.
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