We often use a fully materialistic standpoint to explain what science knows about the origin of the cosmos and of life. This approach stems not only from my own philosophical bent but also from my belief that science and religion should not mix. I think this is an attitude espoused by an enormous majority of scientists. In this view, whether the cosmos and life have a purpose becomes largely irrelevant to the scientist searching for knowledge; we are here to study nature with our brains and our scientific tools, not to decide whether God exists. Once in a while, however, some scientists and other thinkers have crossed the science-religion barrier, usually to defend the notion that nature itself suggests the presence of a deity. One of these thinkers was William Paley, a nineteenth-century opponent of Darwin, well known for his watchmaker metaphor. For Paley a complex object like a watch cannot appear spontaneously— it implies a watchmaker, a designer. And so it goes with life itself, said Paley. This type of argument has recently been revived by neo-creationists— including the American biochemist Michael Behe— who see in living things evidence for the existence of a creator. In general, these individuals are opposed to the theory of evolution in a Darwinian sense, although some have come up with the concept of microevolution, an illdefined mechanism that allows for some genetic flexibility leading to minor evolutionary changes. Like Paley, scientific creationists rely heavily on metaphors, this time invoking “perfect” metabolic pathways and other cellular functions that could not have evolved from less perfect ones. Life must then have been designed. To use one of their metaphors, they say that a perfect bicycle, for example, cannot evolve from metal and rubber or from an imperfect bicycle without the intervention of a designer. Since the designer of a bicycle has a purpose in mind— the transportation of people— and since life was also designed, life (and, by extension, the whole universe) must also have a purpose.
Does our own biochemical complexity point towards intelligent design?
There are serious problems with this type of thinking. First, metabolic pathways are not necessarily perfect. For example, the enzyme ribulose bisphosphate carboxylase/oxygenase— the most abundant protein on planet Earth because it is present in all plants— converts atmospheric carbon dioxide into organic carbon, which is then used to make sugars. But the oxygenase function of this enzyme uses atmospheric oxygen to degrade a portion of the sugars it helps make. These sugars— and the energy consumed by plants to make them— are thus wasted for further metabolic processes. Clearly, this enzyme is quite imperfect. Another argument used by the defenders of the designer hypothesis is the existence of the “perfect” (and very complex) blood-clotting mechanism present in vertebrates, which they say could not have evolved from a less perfect pathway. But now that large parts of the human genome have been sequenced, we know that the human blood-clotting system is present in simpler form in the fruit fly and even in a worm, two invertebrates. Clearly, the complex system found in humans and other vertebrates results from the recruitment of more ancient genes (such as worm and fly genes) often accompanied by their rearrangement. This observation demonstrates that the vertebrate blood-clotting mechanism did in fact evolve from a simpler system and was not designed with a specific purpose in mind. On the contrary, organisms that acquired a more efficient blood-clotting mechanism through evolutionary processes recovered more quickly from injury, and they lived and reproduced more successfully, thereby passing on their better adapted genes.
Interestingly, Dyson Freeman (a famed physicist) is one of the few scientists I know of who explicitly states that the cosmos and life do not make sense without the existence of God. However, as I said earlier, Dyson does not espouse the idea that God is some type of engineer who mapped out the details of the Big Bang and designed living organisms to make them perfect. Dyson’s God is far more subtle. For Dyson, the universe cannot be an accident— that is, a chance event. Indeed, if the masses of elementary particles had been created very different from the existing ones, much of physics and chemistry would have been different, and life as we know it might not have appeared. Similarly, if the four fundamental forces were very different in their relative strengths (for example, if gravity superseded the other three forces), the universe would be a very different place today. Thus Dyson sees in the laws of physics not a proof of the existence of God but an indication that the “architecture of the universe is consistent with the hypothesis that mind plays an essential role in its functioning.” It should be kept in mind that for Dyson, apparently, mind and soul are a single concept. And, indeed, without the presence of a mind (or minds or souls) that tries to understand the universe and discover its laws, the universe might as well not exist. However, Dyson makes it very clear that this is as far as science can go. For him the existence of a world soul (God) is a question that belongs to religion and not to science. 'Dyson the Christian' does believe in a world soul, however, and has thus gone beyond the threshold that 'Dyson the physicist' could not cross.