Atheism and Theism JJ Haldane - Common Sense Atheism
Atheism and Theism JJ Haldane - Common Sense Atheism
Atheism and Theism JJ Haldane - Common Sense Atheism
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212 J.J.C. Smart<br />
to do my best for the theist. The counter-argument would rest largely on<br />
the anthropocentricity (or perhaps biocentricity) of the notion of purpose,<br />
especially as it is elucidated in evolutionary theory as a result of chance <strong>and</strong><br />
natural selection. Even theists are prone to stress the inscrutability of the<br />
nature of God, <strong>and</strong> especially because of the existence of evil, to wonder<br />
about whether God would have purposes in any human sense of the world.<br />
At the best our wonder <strong>and</strong> awe at the existence <strong>and</strong> beauty of the universe<br />
might suggest a form of pantheism more related to F.H. Bradley’s Absolute<br />
or Sankara’s ´<br />
Brahman. (If these notions make sense.)<br />
7 The Fine-Tuning Argument: Bayesian Considerations<br />
Bayes’ theorem in the theory of probability is concerned with the probability<br />
of a hypothesis h given evidence e. It says that<br />
Prob(h/e) = [Prob(e/h) × Prob(h)]/Prob(e)<br />
Thus it helps that e should follow from or be made highly probable by h. It<br />
also helps that h itself should be antecedently probable. Most importantly for<br />
h given e to be high it is important that the antecedent probability of e should<br />
be low. The proponent of the fine-tuning argument puts the antecedent<br />
probability of e to be very low. The lower e, the higher observation of e raises<br />
the probability of h. So the proponent of the fine-tuning argument lays stress<br />
on the fact that the fine tuning is antecedently highly improbable, i.e. that it<br />
is surprising. If h is the theistic hypothesis, the argument persuades us that<br />
the fine tuning e, though antecedently improbable, is quite to be expected<br />
if God exists <strong>and</strong> has created a universe susceptible to the emergence of life<br />
<strong>and</strong> consciousness (<strong>and</strong>, for that matter, such things as stars <strong>and</strong> galaxies).<br />
However, Prob(h) occurs in the numerator of the right-h<strong>and</strong> side of the equation<br />
above. If Prob(h) is very very small it may keep Prob(h/e) small despite<br />
Prob(e) being very small: for example, some people might put the existence of<br />
evil as greatly reducing the probability of the theistic hypothesis.<br />
Still, how small Prob(h) could be depends on the nature of the theistic<br />
hypothesis h. Thus someone might give a very low value to the antecedent<br />
probability of the existence of John Leslie’s God as an ethical principle that<br />
brings value into existence, perhaps because he or she gives a high probability<br />
to non-cognitivism in meta-ethics. Can an ‘is’ somehow be explained by an<br />
‘ought’? (However, in the next section I shall give a half-hearted – or maybe<br />
quarter-hearted – defence of a somewhat Leslie-like position.)<br />
Someone who was convinced of the non-existence of God because of the<br />
existence of evil would put Prob(h) as zero or perhaps infinitesimal. Those of