The Design Argument
Part One: How it works
Colin Crowder
The design argument is the third of the classic ‘theistic proofs’, or arguments for the existence
of God. Students often heave a sigh of relief when they reach it. First, it appears to be a great
deal more ‘user-friendly’ than the ontological and cosmological arguments which so often
precede it in both courses and textbooks. Second, it seems to be refreshingly ‘modern’ (or
relatively so), at home in an intellectual atmosphere which we breathe more easily than we do
that of Anselm, say, or Thomas Aquinas.
Yet appearances can be deceptive, and the design argument is neither modern nor - unfortunately - simple. A historical enquiry could show you just how old the design argument really is.
But this is a philosophical enquiry, and so I shall try to show you that the argument is complex
- but all the more interesting for that.
What I want to do is to bring the design argument into focus. We need to ask what it tries to
do, what it fails to do, and what value, if any, it might still have. So my paper is composed of
three sections:
a: a statement and analysis of the design argument;
b: a critique of the argument at four levels;
c: a contemporary perspective upon the argument.
Part 1 of my paper, in this first issue of Dialogue, is devoted entirely to section A. To help you
to think about the argument, I look at some logic; to encourage you to read about it, I suggest
a bit of further reading.
Part 2 of the paper, in the next issue of Dialogue, takes in sections B and C. I should add that
my remarks about religious language there, like the logical remarks here, can be applied to
many other philosophical topics.
A: Statement and Analysis of the Argument
(1) Let us begin by considering the best-known English champion of the design argument.
William Paley (1743-1805) was a churchman with a strong interest in apologetics - the defence
(apologia) of the truth of Christianity by appeal to ‘natural reason’ rather than to ‘revelation’.
The apologist need not rule out a subsequent appeal to revelation, provided he or she gives
good reasons for believing that any purported divine revelation (such as the Bible) is, in fact,
what it is said to be. But that only underlines the fact that the apologist'’s real job is to argue for
the truth of Christianity in ways acceptable (at least in principle) to all rational people, whether
religious or not. This is very much what we see Paley doing in more than one of his works. As
an apologist of a distinctively eighteenth-century kind, moreover, Paley liked to talk in terms
of the ‘evidences’ of Christianity. What such talk gives us a sense of, perhaps, is the selfunderstanding of the apologist, as one who trusts to the facts of the matter, the hard evidence
available to one and all; it places the apologist in the sober company of the scientist, the
historian and the lawyer. This is Paley's rhetorical strategy, and it is nowhere better displayed
than in his treatment of the design argument.
This treatment is found in Paley's Natural Theology of 1802. Paley imagines himself walking
upon a heath, and coming across a stone. He would not be puzzled by finding it; no
explanation would be needed. But suppose that he had found a watch there instead. He
would be puzzled by its presence; he wouldn't simply treat it (as he had the stone) as the sort
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of thing that might have occurred naturally. The difference between the two cases is two-fold:
the watch (unlike the stone) is composed of finely adjusted parts manifesting orderly
behaviour, and the interaction of these parts serves a specific purpose - telling the time.
Because of these two aspects of the watch - order and purpose - we are obliged to believe that
it is the product of an intelligent designer. Now we reach the crucial stage of the argument:
Paley says that nature is full of things which resemble the watch in those key respects of
orderly complexity and purposeful arrangement. What we recognise in the watch, we must
recognise in the world, only to a vastly higher degree:
[Every] indication of contrivance, every manifestation of design, which existed
in the watch, exists in the works of nature; with a difference, on the side of
nature, of being greater and more, and that in a degree which exceeds all
computation. I mean that the contrivances of nature surpass the contrivances
of art, in the complexity, subtlety, and curiosity of the mechanism; and still
more, if possible, do they go beyond them in number and variety: yet, in a
multitude of cases, are not less evidently mechanical, not less evidently
contrivances, not less accommodated to their end, or suited to their office,
than are the most perfect productions of human ingenuity.
The conclusion seems obvious: if we must argue from watch to watchmaker, we must argue
from world to worldmaker. What watch and world have in common are orderly complexity
and purposeful arrangement, only on a very different scale in each case. Correspondingly,
what watch and worldmaker have in common is that both are intelligent designers, and again,
the difference between them is one of scale.
Paley goes on to devote most of his book to piling up examples of design in the natural world.
From this point onwards the reader is in the hands of the clergyman naturalist, an exquisitely
English type; but that means that the philosopher has done his work. Paley may continue to
illustrate his design argument, but the statement of the argument as such is now complete.
Let us recall what Paley has done. He has considered a mechanism (the watch), and identified
in it certain features. These have compelled us to ascribe the production of the watch to an
intelligent designer. (So far, so good: we know from experience, independently of the
argument, that watchmakers are indeed responsible for watches.) He has then argued that the
natural world is full of things with the same features, things which are, in effect, also
mechanisms showing orderly complexity and purposeful arrangement. And he has concluded
that we must make the same inference as we did in the case of the watch - namely, to an
intelligent designer. It is a case of ‘similar effects, similar causes’. The known designer (that is,
the watchmaker), and the postulated designer (that is, God), are therefore similar in kind, but
dissimilar in degree. And this is the same distinction that was deployed to express the ways in
which our machines and the natural world are alike and not alike.
(2) Before I attempt to ‘unpack’ these ideas a little more, I would like to give you another
example of the design argument. It is taken from the work of David Hume (1711-1776), a
Scottish philosopher and historian, who crops up in connection with the design argument just
as often as Paley does. His key work in this connection is Dialogues Concerning Natural
Religion, published posthumously (in 1779), but drafted over twenty years earlier - hence
predating Paley's Natural Theology by nearly half a century. The Dialogues are much more
entertaining than any treatise, since in them Hume creates three memorable characters who
try to outmanoeuvre one another, not always very fairly, in arguing about the existence of
God. Although a sceptical character, Philo, is allowed to run rings around the others, a
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somewhat Paleyesque character called Cleanthes makes a lot of the early running. The speech
from which the following summary of the design argument comes is, perhaps, his finest hour:
Look round the world: contemplate the whole and every part of it: You will
find it to be nothing but one great machine, subdivided into an infinite
number of lesser machines, which again admit of subdivisions, to a degree
beyond what human senses and faculties can trace and explain. All these
various machines, and even their most minute parts, are adjusted to each
other with an accuracy, which ravishes into admiration all men, who have
ever contemplated them. The curious adapting of means to ends, throughout
all nature, resembles exactly, though it much exceeds, the productions of
human contrivance; of human design, thought, wisdom, and intelligence.
Since therefore the effects resemble each other, we are led to infer, by all the
rules of analogy, that the causes also resemble: and that the Author of nature
is somewhat similar to the mind of man; though possessed of much larger
faculties, proportioned to the grandeur of the work, which he has executed.
By this argument a posteriori, and by this argument alone, we do prove at
once the existence of a Deity, and his similarity to human mind and
intelligence.
There are a couple of technical ideas there which I will come back to shortly. For now, what
we should note is the way in which Hume'’s statement (through Cleanthes) of the design
argument brings out the ideas we saw at work in Paley's formulation:
- note again the idea that the world and its parts are mechanisms, comparable to the ones we
ourselves produce;
- note again the concern with both order (the accurate adjustment of parts to one another) and
purpose (the adaptation of means to ends) in natural mechanisms;
- note again the principle of ‘similar effects, similar causes'’ which is the argument’s backbone;
- note again the concern with proportion; although the makers of ‘artificial’ and ‘natural’
mechanisms are similarly intelligent, there is a huge difference between them corresponding
to the huge difference between their products. This is essentially a matter of scale: the
unknown designer must be like the known, human designer, only much more so, since the
work of the former so completely dwarfs the work of the latter which it otherwise closely
resembles.
By now we should be getting a little clearer about what is going on in the design argument.
Obviously, it isn't just a matter of saying ‘there must be a God because the world is so complex
and amazing’ - although, as I hope to indicate later, I don't want to ignore the element of awe
from which the argument profits. But the design argument as an argument needs patient
unpacking. So far I have tried to set out some of the basic stages of the argument, at least as it
appears in the work of Paley and Hume. What I want to do now is to carry the analysis a little
further, by asking how the design argument should be characterised.
(3) (a) I can begin by quickly mentioning some informal characteristics of the argument - the
ones which strike us first, and perhaps linger longest in the mind.
What I have in mind is the argument's ‘user-friendly’ character, which I mentioned at the
beginning of this paper. It is easy to get the hang of the design argument, even if we don't
understand its inner workings particularly well - and we can't say that of all the classic theistic
proofs. The argument presents itself as vivid, accessible, and ‘common-sensical’, with its feet
firmly on the ground. It makes use of things with which we are familiar in daily life - clocks
and houses, plants and animals - and is flexible enough to range from gastropods to galaxies in
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its tireless accumulation of examples of purported divine design. It can capitalise on moods as
distinct as scientific curiosity and religious awe, reserving its suspicion for philosophical
abstraction, which it seeks to replace by a no-nonsense appeal to our everyday experience of
the human and natural world. Is it any wonder that its persuasive power outstrips (as we shall
see) its logical force? Even the great German philosopher Immanuel Kant (1724-1804), who
punctured the pretensions of the ontological and cosmological arguments, and who seemed
set to deal the design argument a devastating blow, went out of his way to cushion his
criticisms of it:
This proof always deserves to be mentioned with respect. It is the oldest, the
clearest, and the most accordant with the common reason of mankind.
He is not alone in having a soft spot for an argument he nevertheless believes to be false. As
arguments go - not least theistic arguments - this one is downright amiable.
(b) It is time to turn to some formal characteristics of the argument. Setting these out will help
us to see rather more clearly what the argument is, and is not.
First, the design argument is an a posteriori argument, not an a priori one. We shouldn't let
the Latin tag dazzle us, since the distinction being made here is quite straightforward. In the
case of propositions, one that is a priori (`from what comes before') can be known to be true
or false without reference to experience. One that is a posteriori (`from what comes after') can
only be known to be true or false by reference to experience, to how things actually are in the
world. Take an example: `All bachelors are unmarried'. We don't need to conduct a survey
to find out if this is true - we can see it is true because of the meaning of the words themselves.
It is therefore true a priori (just as `No bachelors are unmarried is false a priori). But if I say,
instead, `all Norwegians are unmarried', the truth or falsity of the proposition depends upon
an actual state of affairs. You must know something about the relevant facts to be able to judge
the truth or falsity of an a posteriori proposition. In the case of arguments, the a priori ones
are staking claims on the back of the corresponding propositions. This is what the ontological
argument does, in attempting to deduce the existence of God from the concept of God alone.
The design argument is an a posteriori argument, because it relies upon things being a certain
way not just in the order of concepts but in the order of reality too. (It is a relatively rich a
posteriori argument, it might be added in typically appealing to a lot of facts, often highly
specific ones; the cosmological argument, by contrast really depends upon one fact, a highly
general one at that: the shear existence of the universe.) This characteristic, then, is the logical
foundation upon which is built that sense of the design argument as being `down to earth',
`factual', `scientific', and so forth.
Second, the design argument is an inductive argument. This isn't quite so obvious as the formal characteristic I have just noted, and so my claim needs to be developed a little. Again, let
us consider the alternative, by asking what the design argument would look like if it were a
deductive argument instead. Deductive arguments are particularly strong ones, since their
conclusions follow `automatically' from their premises. So, for instance, if we have two
premises:
(a) `Socrates is a man'
(b) `All men are mortal'
Then the conclusion (c), `Socrates is mortal', is just as sound as the premises, which in this
case are certain. To deny the conclusion would be to deny the premises; alternatively, the
premises can be said to `contain' the conclusion, which we simply have to `bring out'. Not
surprisingly, then, many arguments would like to join the deductive club, because deduction
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provides such a `strong' logical connection between premises and conclusions. But look what
happens if we state the design argument in a would-be deductive form:
(a) `Nature is full of designed things'
(b) `Designed things are attributable to designers'
(c) `Therefore, nature is attributable to a
designer'
There is more than one logical sleight-of-hand here, but what really matters is that the
conclusion can be no better than the weakest premise. This premise is the first one, which
asserts something which the design argument is, in fact, obliged to prove. I could tighten up
the argument above in order to remove some mismatches (between things in nature and
nature as a whole, between designers and a designer), but I couldn't eliminate the
unacceptable premise. At best I could put the weak link elsewhere:
(a) `Nature is full of orderly structures'
(b) `Orderly structures are products of intelligence'
(c) `Therefore, nature is the product of intelligence'
Now it is the second premise which assumes what has to be proved. Again, the conclusion is
unproven because a key premise is uproven.
There is no alternative, then, but to reconstruct the design argument in inductive terms. In
induction, we move from premises about some things of a certain kind to conclusions about
other or all things of that kind: we could argue, for instance, that `All swans are white', on the
basis of those swans that we know about. If not as `strong' as deduction, induction can still be
very secure in certain cases. Consider how this affects the design argument. The `weak
premise' identified above needs to be defended, because the whole argument rests upon it.
But it can only be defended inductively:
(a) `Some orderly structures are products of intelligence'
(b) `Therefore [it is reasonable to believe that] all orderly structures are products of
intelligence.'
Well, perhaps. There are, of course, ways in which the inference from `some' to `all' here
can be frustrated. But at least we can see that inductive reasoning will have to have a place in
the design argument, and that it is deceptive to dress up the argument as a deductive proof
relying upon self-evidently true premises. (Moreover, the distinction being made here will
become clearer when we consider the next formal characteristic of the argument.)
Third, the design argument is analogical. Following the pattern I used with regard to the
previous two characteristics, let us first try to imagine what a non-analogical inductive design
argument would look like:
(a) `Most [or all] other universes are known to be the product of intelligent design'
(b) `Therefore, this particular universe is probably the product of intelligent design'
The problem with this, obviously, is that universes don't come in batches. The very concept of
the universe puts it in a class of one, and this means that we cannot argue straightforwardly
(i.e. non-analogically) from some members of the class of universes to another member. The
kind of argument outlined above works well enough for machines, say, but cannot work for
universes.
But my mention of machines should remind you of the way in which the design argument
actually operates. It starts with things held to be analogous to the universe (or parts of it), such
as machines, and argues that the cause of apparently `designed' properties in the universe
must therefore be analogous to the known cause of undoubtedly designed properties in
machines. Put simply, the world is similar to a watch, so the worldmaker must be similar to a
watchmaker - making the necessary adjustments for the scale of the handiwork, of course.
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You should now think back to the quotations from Paley and from Hume's Cleanthes, and
consider the way in which they manifest this analogical character of the design argument. You
should also note that analogical reasoning is weaker than straightforward inductive reasoning:
it forces us to deal with two classes of things rather than one, and it is perfectly possible to
make the wrong comparison between the classes at the outset. But analogical reasoning
certainly isn't valueless. (Hume, interestingly, goes too far at this point: he suggests we cannot
form rational hypotheses about the cause of this universe because we don't have any
experience of other universes to give us something to go on. Well, if we had the relevant
experience, we wouldn't need to argue analogically in the first place, would we? We could
argue directly from items in the same class. Moreover, if Hume was right we couldn't trust any
analogical arguments, or say anything sensible about apparently `one-off' phenomena either.
Think what this would mean for theories about the Big Bang, or the evolution of life. So,
Hume's reminder about the `singularity' of the universe is important, naturally, and can stop
us from falling into some kinds of logical nonsense. But it does not, in itself, mean the end of
the road for the design argument, which is an analogical argument precisely because of the
otherwise insuperable problem of the singularity of the universe.)
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In the next issue of Dialogue I shall investigate whether the logical structure of the design argument - as set out here - helps it stand up against the attacks of its critics, or whether it is the
logic in particular which is its problem. I shall also ask if the design argument has anything left
to say to us if it cannot prove to us what it sets out to prove.
In the meantime, you could conduct your own analysis of the argument, and develop your
own ideas concerning its philosophical persuasiveness and religious value, for example. Here
are some ideas for further reading:
Most of the modern introductions to the philosophy of religion have useful sections on the
argument. e.g.:
H.D. Lewis, Philosophy of Religion (1965)
T. McPherson, The Philosophy of Religion (1965)
J. Hick, Philosophy of Religion (2nd ed., 1973)
B. Davies, An Introduction to the Philosophy of Religion (1982)
J.C.A. Gaskin, The Quest for Eternity (1984)
C.S. Evans, Philosophy of Religion (1985)
There are many other introductions like these, so my list - of believers and atheists, Catholics
and Protestants, conservatives and liberals - is merely a starting-point.
Paley's Natural Theology turns up in a variety of old editions; some libraries have a handy
abridgement, edited by Frederick Ferr (1962). The secondary sources tend to quote most of
the important parts anyway.
Hume's Dialogues Concerning Natural Religion can be found in many modern editions, the
`standard' one being that of Norman Kemp Smith (1935/47). Stanley Tweyman's Routledge
paperback edition (1991) contains lots of good critical material; Martin Bell's Penguin
paperback (1990) is slim, cheap, and worth buying. Although it is quoted at length in the
secondary sources there is much to be said for reading the original, especially for Hume's wit.
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