by David Kordahl
I’ll start this column with an over-generalization. Speaking roughly, scientific models can be classed into two categories: mechanical models, and actuarial models. Engineers and physical scientists tend to favor mechanical models, where the root causes of various effects are specified by their formalism. Predictable inputs, in such models, lead to predictable outputs. Biologists and social scientists, on the other hand, tend to favor actuarial models, which can move from measurements to inferences without positing secret causes along the way. By calling these latter models “actuarial,” I’m encouraging readers to think of the tabulations of insurance analysts, who have learned to appreciate that individuals may be unpredictable, even as they follow predictable patterns in the aggregate.
Operationally, these categories refer to different scientific practices. What I’ve called a difference between mechanical vs. actuarial models could just as well be sketched as a difference between theory-driven vs. data-driven models. Both strains have coexisted in science for the past few centuries.
Just for fun, we might attempt to caricature the history of modern science in the mechanical vs. actuarial terms introduced above. In the seventeenth century, Isaac Newton proposed a law of universal gravitation, applicable everywhere throughout the universe, which allowed naturalists to imagine that all physical effects, everywhere and for all time, were caused by physical laws, just waiting to be discovered. This view was developed to its philosophical extreme in the eighteenth century by the French mathematician, Pierre Laplace, who imagined that the universe at any particular moment implicitly contained the specifications for its entire past and future.
But in the nineteenth century, Charles Darwin introduced his theory of natural selection, which allowed naturalists to take actuarial models more seriously. Just as hidden order could cause the appearance of randomness, hidden randomness could cause the appearance of order. Read more »
by Paul Braterman
Watercolour, Darwin after return from The Beagle, by George Richmond
Charles Darwin regarded our minds, like our bodies, as the products of undirected evolution. He therefore considered them unreliable on topics vastly more abstruse than the experiences that had shaped them. Alvin Plantinga claims that minds produced by undirected evolution could not even be trusted to interpret day-to-day experience. From this he infers that undirected evolution is false, and belief in it self-contradictory. Darwin doubts our capacity to think sensibly about whether or not there is a God, while Plantinga regards the fact that we can think about reality at all as proof of His existence. In Part II of this essay, I will discuss Plantinga's views in more detail, and show that they arise, not so much from anything unusual in his epistemology, as in a profound misunderstanding of the workings of evolution.
Darwin's correspondence includes extensive discussion of religious matters, but it could be argued that what he says there is tempered to his audience. However, his private Autobiography includes a short but revealing chapter on religious belief, and that is what I mainly drawn on here. The family regarded this as so contentious that it was not made public in full until 1958, and I see no reason to regard it as anything less than a full and open account. In less than four thousand words, he traces his progress from rigid orthodoxy to a principled rejection of all dogmatic positions. In the process, he lays out with admirable brevity the standard arguments against religion, using language so clear and striking that one hears echoes of it today, even, perhaps unwittingly, in the arguments used by his opponents.
Darwin initially contemplated becoming a clergyman. He tells us that he “did not then in the least doubt the strict and literal truth of every word in the Bible”, and was much impressed by Paley's argument from the perfection of individual organisms to the existence of an intelligent creator. He was still quite orthodox while on the Beagle, but in the two years after his return he reconsidered his position, and gradually came to reject orthodox religion for many reasons. Old Testament history is manifestly false (he cites the Tower of Babel, and the rainbow as a sign given to Noah), and describes its God as having the feelings of “a revengeful tyrant.” As for the New Testament, the beauty of its morality may be due to selective interpretation. The New Testament miracles (and here I think he includes the Virgin Birth and the Resurrection) beggar belief in a more scientific age, and the Gospels describing them are mutually contradictory, and written long after the events they claim to describe. For a while, he hoped that new archaeological discoveries would confirm the Gospel story, but gradually he moved towards total rejection on moral, as well as historical and logical, grounds.
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