26.1 Causal explanations

Darwin, in fact, was motivated to develop his theory of evolution via natural selection because he precisely wanted to follow the then new naturalistic theory of causation. It was the theory in which God was not involved in the day-to-day running of the universe. From an early stage, Darwin looked for a theory in which a self-sustaining and self-developing natural world could produce all the living creatures seen today without God being responsible for its details and (in particular) not being responsible for the disease, predation, and parasitism that he saw. We may debate whether or not Darwin’s theory is plausible or successful with its causal explanations. However, within the absent-God causal scenario, it is clear that it is more or less the only possible explanation. As a result, it has today a very large number of followers. Many of them are still seeking the detailed causal explanations but uniformly agree on the ‘sanctity’ of the laws of nature within a naturalist philosophy.

There are many scientists who do profess religion and think that theism and Darwin’s theory can co-exist. This compatibility is possible since theism means to them that God sustains the world, and Darwin has described how creatures in the world have functioned and developed together.^26.1This view, however, is equivalent to deism, not theism. It holds that God is not involved with the world once its operation has started (except, perhaps, in special events such as the founding and/or culmination of new religions). Once ‘laws of nature’ are assumed to be inviolate, Darwinism can accommodate such deistic views.

Within our new scientific theism we are unable to follow Darwin, in either the naturalistic or deistic world views. When God sustains the universe, this is not accomplished ‘at a distance’ by ‘merely sustaining’ the universe according to laws of physics but (we now conclude) by the presence of God in some degree. There can be no power without substance and no substance without present existence, as was argued in Chapter 4. This means that any sustaining action of God in the world will necessarily require the reception of life from God, not abstractly but as a substance really existing. This life is not always according to fixed physical laws. It necessarily has spiritual and mental components that will be effective if a suitable receptive form (e.g. a human form) is present. The fitness of a living organism is not purely a function of its interactions with the physical world and other organisms. It depends also and at least on the fullness of its reception of life from God. This implies that, within a proper theism, it is impossible to have a purely naturalistic account of evolution. Fitness, and hence selection, are not entirely natural. They are subject also to spiritual and mental considerations.

One common alternative to the theory of natural selection is the theory of intelligent design. The intelligent design theory, however, is deliberately limited, as it does not attempt a causal explanation. It tries to develop techniques to examine physical organisms and then to determine whether or not that examination provides evidence for the existence of an intelligence in the coming to be (or design) of those organisms. Strictly, it is neutral on whether the intelligence is God or whether it might be previously-existing extra-terrestrial beings who have (say) genetically-engineered the organism. Because intelligent design theory does not produce causal accounts, it is often criticized as lacking in predictive power. It does make general ‘structural’ predictions about the forms expected to occur within living organisms, but it will never, it seems, yield the detailed prior and conditional probabilities necessary to form Bayesian arguments of the kind that many scientists use to assess the likelihoods of the hypotheses they are considering. See, for example, the discussion by Sober (2002).

Intelligent design theory has generated an extraordinary amount of animosity from mainstream (naturalistic) scientists. They often accuse it of being false. Then they simultaneously accuse it of being non-scientific because non-falsifiable! By comparison, theistic science is advocating a much stronger theory than intelligent design since it cannot be neutral about ‘the nature of the designer’. We start from the assumption that God exists, as being itself and life itself.

Another common alternative to natural selection is creationism, where different species are created individually and specifically by God according to the first chapter of Genesis that culminates in the creation of man (and woman). These acts of creation, with whole new populations of plants or animals coming into existence, would have been rather spectacular to watch! Are such special creations possible according to theistic science? The answer, we next see, is no.