Design Arguments

Design Arguments
Arguments for theism
• Ontological arguments
• Cosmological arguments
• Design arguments
Ontological arguments
• Attempt to establish the existence of God a
priori (not based on any facts known by
• It follows from the very idea of a theistic god
that such a being must exist
• A theistic god by definition has all perfections
• Existence is a perfection
• Thus, a theistic god exists
Cosmological arguments
• Attempt to show that the very existence of the
cosmos—any cosmos--must be explained by
saying that it was created by a supernatural
• It doesn’t matter what the cosmos is like; it
must have a divine origin
Design arguments
• The world has some special feature that is best
explained by supposing that it was designed that
way by a rational being.
• This feature cannot have been designed by any
inhabitant of the cosmos.
• It’s reasonable to accept the best explanation for
something known to be the case.
• So it is reasonable to conclude that there is a
supernatural being who designed the cosmos.
• Also called ‘teleological arguments’, since they
appeal to purposes or goals
The central premise
• The cosmos has some special feature that is
best explained as the product of intelligent
design by some sort of god.
• Some possible universes show evidence of
intelligent design and others don’t.
• What sort of feature would count as evidence
of intelligent design?
length: 7.890348761229cm
width: 3.980012563422cm
height: 4.39976130025cm
mass: 1.082230076113kg
The Question
Can we find any objects or features of the world
that appear to have been designed, but were
not designed by human beings or other
inhabitants of the cosmos?
Why are there living organisms?
1. They were designed by an intelligent nonorganism: a supernatural being
2. Or maybe they came about by some natural
process involving evolution by natural selection.
• Organisms are born with random variations.
• Some of these variations are advantageous.
• Those organisms that have these traits are more
likely to reproduce.
• Their offspring inherit the advantageous traits.
What evolution by natural selection
doesn’t explain
Where did the first organisms come from?
Why is the universe conducive to life?
It didn’t have to be that way.
That the universe is conducive to life is very
The gravitational constant
G = 6.67384 x 10-11 N(m/kg)2
Other numbers ‘filled in by hand’: the masses of
the proton and neutron, the charge on the
electron, the strength of the electromagnetic
force, and many more
What would the universe be like if
these numbers were different?
• If they were even slightly different—in some
cases by one part in 1055--life would be
• There would be no atoms, or no stars, or only
very short-lived stars,…
A universe-making machine
The pointer on dial 18 reads .0082301766. If it were not
set at a value between .0082301761 and .0082301768,
there would be no carbon atoms and hence no life.
The pointer on dial 12 reads 629.089271, and the pointer on
dial 4 reads 629.089268. If the difference between these
readings were greater than .000005, all stars would burn out
within a few thousand years; if they were exactly equal, there
would be no matter but only radiation.
The proportion of possible universes (with the same
general laws as ours) that contain stars has been
estimated at 1 in 10229.
Why are the dials set so as to make life
• By design: Some rational being set the dials as
they are in order to create a universe
containing life
• Why would a rational being want to create a
universe with life in it?
• We don’t need to answer this question in
order to know that the cosmos was designed.
The fine-tuning argument
1. The best explanation of the fact that the
universe is hospitable to life (if not the only
explanation) is that it was designed that way
by a supernatural being
2. It’s reasonable to accept the best explanation
for something we know to have occurred.
3. So we should conclude that the universe was
designed by a supernatural being.
The fine-tuning argument: three
1. Does the fact that the universe is hospitable
to life need any explanation at all?
2. Is the design hypothesis a good explanation
of that fact?
3. Is there another explanation equally good?
1. Does the fact need any explanation?
• The dials just happen to be set as they are by
• That may be unlikely, but unlikely things do
• The dials had to be set somehow, and their
actual settings are is no less likely than any
other settings.
• We were just lucky.
2. Is the design explanation a good
• It doesn’t explain the existence of the Designer
• It doesn’t explain the existence of organized complexity
• Both points are correct, but irrelevant.
• Even if the design hypothesis does not explain the
existence of organized complexity, it might explain why
the universe is conducive to life.
• Any explanation of a contingent fact will appeal to
something else that it doesn’t explain.
• The hypothesis that the Martian watch was dropped by
the Americans leaves many facts unexplained.
3. Is there any other explanation?
• The machine had to be fine-tuned for life, because
otherwise there wouldn’t be anyone here to ask any
questions. So no further explanation is needed.
• There had to be a working watch lying in the Martian
sand, because otherwise you wouldn’t have found one
there. So no further explanation is needed.
• The fact that you found a watch shows that there is
one there, but not why there is.
• The fact that there is life in the universe shows that the
machine is fine-tuned for life, but not why it is.
Is there any other explanation?
• The numbers had to be the way they are.
• The possible universes where the numbers are
incompatible with life are not really possible.
• The dials could not have been set in a way
that produced a universe with no stars, or
where all matter is violently radioactive,…
• But there is no reason to believe this, and on
present evidence it looks very unlikely.
The ‘multiverse’ hypothesis
• Our universe is one of many actual, concrete
• In every universe the numbers are different.
• The machine’s dials are set and reset at random
many times, and each time it produces another
• There are so many different universes that it’s
likely that at least one will be life-permitting.
• It’s not surprising that that’s the universe we live
in, since there are no philosophers in any of the
The ‘multiverse’
• You catch a fish 9.24102 inches long.
• No surprise: every fish has some length, and
there’s nothing special about that one.
• But your fishing gear can only catch fish that
are 9.24102 inches long ± one part in a
Why did you catch a fish 9.24102
inches long?
1. Someone knew about your fishing gear, and put
a fish of that length in the lake for you to catch:
a design explanation.
2. There are millions of fish of different lengths in
the lake, so many that one of them is bound to
be 9.24102 inches long: analogous to the
‘multiverse’ explanation.
• It’s no surprise that you caught that one, since it's
the only one you can catch.
3. There is only one fish in the lake, and by good
luck it just happened to be 9.24102 inches long:
no explanation.
Now what?
• It’s reasonable, at least, to accept the best
available explanation of something we know
to be the case.
• Suppose the design hypothesis and the
‘multiverse’ are both good explanations of
why the universe is life-permitting, and there
are no other good explanations.
• Which explanation is better?
Which explanation is better?
• The ‘multiverse’ explanation is extravagant.
• There are not merely many possible universes.
• There are trillions of actual, concrete
• For some reason we are able to observe only
• It may not be a proper scientific hypothesis.
Which explanation is better?
• The design explanation is equally extravagant,
even if it doesn’t specify the precise nature of
the Designer.
• It appeals to a supernatural being, which for
some reason we are unable to observe.
• It’s no more ‘scientific’ than the multiverse
Which explanation is better?
• Some say the design hypothesis is simpler, as
it posits only one object rather than trillions
• Others say the ‘multiverse’ hypothesis is
simpler, since it posits only objects of the
same sort that we already know to exist.
• Both are extravagant, but in different ways.
Tentative conclusion
• Suppose the ‘multiverse’ hypothesis is a good
explanation of why the universe (or some
universe) is life-permitting.
• It’s not obviously a worse explanation than
the design hypothesis
• Then the design argument is inconclusive.
• At best it shows this: either there is a
supernatural designer, or there are many
other universes.