Read The Beginning of Infinity: Explanations That Transform the World Online
Authors: David Deutsch
There are even examples of
non
-functional design. For instance, most animals have a gene for synthesizing vitamin C, but in primates, including humans, though that gene is recognizably present, it is faulty: it does not do anything. This is very difficult to account for except as a vestigial feature that primates have inherited from non-primate ancestors. One could retreat to the position that all these apparently poor design features do have some undiscovered purpose. But that is a bad explanation: it could be used to claim that
any
poorly designed or undesigned entity was perfectly designed.
Another assumed characteristic of the designer according to most religions is benevolence. But, as I mentioned in
Chapter 3
, the biosphere is much less pleasant for its inhabitants than anything that a benevolent, or even halfway decent, human designer would design. In theological contexts this is known as ‘the problem of suffering’ or ‘the problem of evil’, and is frequently used as an argument against the existence of God. But in that role it is easily brushed off. Typical defences are that perhaps morality is different for a supernatural being; or perhaps we are too limited intellectually to be able to understand how moral the biosphere really is. However, here I am concerned not with whether
God exists, only with how to explain biological adaptations, and in that regard those defences of creationism have the same fatal flaw as the Haldane–Dawkins argument (
Chapter 3
): a world that is ‘queerer than we
can
suppose’ is indistinguishable from a world ‘tricked out with magic’. So all such explanations are bad.
The central flaw of creationism – that its account of how the knowledge in adaptations could possibly be created is either missing, supernatural or illogical – is also the central flaw of pre-Enlightenment, authoritative conceptions of
human
knowledge. In some versions it is literally the same theory, with certain types of knowledge (such as cosmology or moral knowledge and other rules of behaviour) being spoken to early humans by supernatural beings. In others, parochial features of society (such as the existence of monarchs in government, or indeed the existence of God in the universe) are protected by taboos or taken so uncritically for granted that they are not even recognized as ideas. And I shall discuss the
evolution
of such ideas and institutions in
Chapter 15
.
The prospect of the unlimited creation of knowledge in the future conflicts with creationism by undercutting its motivation. For eventually, with the assistance of what we would consider stupendously powerful computers, any child will be capable of designing and implementing a better, more complex, more beautiful, and also far more moral biosphere than the Earth’s, within a video game – perhaps by placing it in such a state by fiat, or perhaps by inventing fictional laws of physics that are more conducive to enlightenments than the actual laws. At that point, a supposed designer of
our
biosphere will seem not only morally deficient, but intellectually unremarkable. And the latter attribute is not so easy to brush aside. Religions will no longer want to claim the design of the biosphere as one of the achievements of their deities, just as today they no longer bother to claim thunder.
Spontaneous generation is the formation of organisms not as offspring of other organisms, but entirely from non-living precursors – for example, the generation of mice from a pile of rags in a dark corner. The theory that small animals are being spontaneously generated like
that all the time (in addition to reproducing in the normal way) was part of unquestioned conventional wisdom for millennia, and was taken seriously until well into the nineteenth century. Its defenders gradually retreated to ever smaller animals as knowledge of zoology grew, until eventually the debate was confined to what are now called micro-organisms – things like fungi and bacteria that grow on nutrient media. For those, it proved remarkably difficult to refute spontaneous generation experimentally. For instance, experiments could not be done in airtight containers in case air was necessary for spontaneous generation. But it was finally refuted by some ingenious experiments conducted by the biologist Louis Pasteur in 1859 – the same year in which Darwin published his theory of evolution.
But experiment should never have been needed to convince scientists that spontaneous generation is a bad theory. A conjuring trick cannot have been performed by real magic – by the magician simply commanding events to happen – but must have been brought about by knowledge that was somehow created beforehand. Similarly, biologists need only have asked: how does the knowledge to construct a mouse get to those rags, and how is it then applied to transform the rags into a mouse?
One attempted explanation of spontaneous generation, which was advocated by the theologian St Augustine of Hippo (354–430), was that all life comes from ‘seeds’, some of which are carried by living organisms and others of which are distributed all over the Earth. Both kinds of seed were created during the original creation of the world. Both could, under the right conditions, develop into new individuals of the appropriate species. Augustine ingeniously suggested that this might explain why Noah’s Ark did not have to carry impossibly large numbers of animals: most species could regenerate after the Flood without Noah’s help. However, under that theory organisms are
not
being formed purely from non-living raw materials. That distributed kind of seed would be a life form, just as a real seed is: it would contain all the knowledge in its organism’s adaptations. So Augustine’s theory – as he himself stressed – is really just a form of creationism, not spontaneous generation. Some religions regard the universe as an ongoing act of supernatural creation. In such a world, all spontaneous generation would fall under the heading of creationism.
But, if we insist on good explanations, we must rule out creationism, as I have explained. So, in regard to spontaneous generation, that leaves only the possibility that the laws of physics might simply mandate it. For instance, mice might simply
form
under suitable circumstances, like crystals, rainbows, tornadoes and quasars do.
That seems absurd today, because the actual molecular mechanisms of life are now known. But is there anything wrong with that theory itself, as an explanation? Phenomena such as rainbows have a distinctive appearance that is endlessly repeated without any information having been transmitted from one instance to the next. Crystals even behave in ways that are reminiscent of living things: when placed in a suitable solution, a crystal attracts more molecules of the right kind and arranges them in such a way as to make more of the same crystal. Since crystals and mice both obey the same laws of physics, why is spontaneous generation a good explanation of the former and not of the latter? The answer, ironically, comes from an argument that was originally intended to justify creationism:
The ‘argument from design’ has been used for millennia as one of the classic ‘proofs’ of the existence of God, as follows. Some aspects of the world appear to have been designed, but they were not designed by humans; since ‘design requires a designer’, there must therefore be a God. As I said, that is a bad explanation because it does not address how the knowledge of how to create such designs could possibly have been created. (‘Who designed the designer?’, and so on.) But the argument from design can be used in valid ways too, and indeed its earliest known use, by the ancient Athenian philosopher Socrates, was valid. This issue was:
given
that the gods have created the world, do they care what happens in it? Socrates’ pupil Aristodemus had argued that they do not. Another pupil, the historian Xenophon, recalled Socrates’ reply:
SOCRATES:
Because our eyes are delicate, they have been shuttered with eyelids that open when we have occasion to use them . . . And our foreheads have been fringed with eyebrows to prevent damage from
the sweat of the head . . . And the mouth set close to the eyes and nostrils as a portal of ingress for all our supplies, whereas, since matter passing out of the body is unpleasant, the outlets are directed hindwards, as far away from the senses as possible. I ask you, when you see all these things constructed with such show of foresight, can you doubt whether they are products of chance or design?
ARISTODEMUS:
Certainly not! Viewed in this light they seem very much like the contrivances of some wise craftsman, full of love for all things living.
SOCRATES:
And what of the implanting of the instinct to procreate; and in the mother, the instinct to rear her young; and in the young, the intense desire to live and the fear of death?
ARISTODEMUS:
These provisions too seem like the contrivances of someone who has determined that there shall be living creatures.
Socrates was right to point out that the
appearance of design
in living things is something that needs to be explained. It cannot be the ‘product of chance’. And that is specifically because it signals the presence of knowledge. How was that knowledge created?
However, Socrates never stated what constitutes an appearance of design, and why. Do crystals and rainbows have it? Does the sun, or summer? How are they different from biological adaptations such as eyebrows?
The issue of what exactly needs to be explained in an ‘appearance of design’ was first addressed by the clergyman William Paley, the finest exponent of the argument from design. In 1802, before Darwin was born, he published the following thought experiment in his book
Natural Theology
. He imagined walking across a heath and finding a stone, or alternatively a watch. In either case, he imagined wondering how the object came to exist. And he explained why the watch would require a wholly different kind of explanation from that of the stone. For all he knew, he said, the stone might have lain there for ever. Today we know more about the history of the Earth, so we should refer instead to supernovae, transmutation and the Earth’s cooling crust. But that would make no difference to Paley’s argument. His point was: that sort of account can explain how the stone came to exist, or the raw materials for the watch, but it could never explain the watch itself.
A watch
could not
have been lying there for ever, nor could it have formed during the solidification of the Earth. Unlike the stone, or a rainbow or a crystal, it could not have assembled itself by spontaneous generation from its raw materials, nor could it
be
a raw material. But why not, exactly, asked Paley: ‘Why should not this answer serve for the watch as well as for the stone; why is it not as admissible in the second case as in the first?’ And he knew why. Because the watch not only
serves
a purpose, it is
adapted
to that purpose:
For this reason, and for no other, viz., that, when we come to inspect the watch, we perceive (what we could not discover in the stone) that its several parts are framed and put together for a purpose, e.g., that they are so formed and adjusted as to produce motion, and that motion so regulated as to point out the hour of the day.
One cannot explain why the watch is as it is without referring to its purpose of keeping accurate time. Like the telescopes that I discussed in
Chapter 2
, it is a rare configuration of matter. It is not a coincidence that it can keep time accurately, nor that its components are well suited to that task, nor that they were put together in that way rather than another. Hence
people
must have designed that watch. Paley was of course implying that all this is even more true of a living organism – say, a mouse.
Its
‘several parts’ are all constructed (and appear to be designed) for a purpose. For instance, the lenses in its eyes have a purpose similar to that of a telescope, of focusing light to form an image on its retina, which in turn has the purpose of recognizing food, danger and so on.
Actually, Paley did not know the overall purpose of the mouse (though we do now – see ‘Neo-Darwinism’ below). But even a single eye would suffice to make Paley’s triumphant point – namely that the evidence of apparent design for a purpose is not only that the parts all serve that purpose, but that if they were slightly altered they would serve it less well, or not at all. A good design is
hard to vary
:
If the different parts had been differently shaped from what they are, of a different size from what they are, or placed after any other manner, or in any other order, than that in which they are placed, either no motion at all would have been carried on in the machine, or none which would have answered the use that is now served by it.
Merely being useful for a purpose, without being hard to vary while still serving that purpose, is not a sign of adaptation or design. For instance, one can also use the sun to keep time, but all its features would serve that purpose equally well if slightly (or even massively) altered. Just as we transform many of the Earth’s non-adapted raw materials to meet our purposes, so we also find uses for the sun that it was never designed or adapted to provide. The knowledge, in that case, is entirely in us – and in our sundials – not in the sun. But it
is
embodied in the watch, and in the mouse.
So, how did all that knowledge come to be embodied in those things? As I said, Paley could conceive of only one explanation. That was his first mistake:
The inference we think is inevitable, that the watch must have had a maker . . . There cannot be design without a designer; contrivance without a contriver; order without choice; arrangement without anything capable of arranging; subserviency and relation to a purpose without that which could intend a purpose; means suitable to an end . . . without the end ever having been contemplated or the means accommodated to it. Arrangement, disposition of parts, subserviency of means to an end, relation of instruments to a use imply the presence of intelligence and mind.