112 J.J. Haldane
highly regular, some less so, some fairly chaotic, some utterly so, then it will
be sufficient explanation of the general regularity and particular fine tuning of
our universe that is it but one of indefinitely many. Chance alone will explain
its existence. Given enough opportunities the realization of order becomes
unpuzzling.
Note that the question of whether to conclude to design or chance is not
one that scientific observation can decide. We need to reason our way ahead.
How reasonable, therefore, is the reduction of order to chance? It is not true
to say that because any other outcome might have occurred a particular one
requires no explanation. One way of bringing this out is in terms of signific-
ant orderings. Suppose someone photocopies the pages of this book num-
bered 1 to 100, thoroughly shuffles them and stacks them in a pile. Assuming
relevantly similar causal antecedents any stacking has the same prior probabil-
ity as any other – 1 in 3,628,800, and under the description ‘papers in a pile’
no particular arrangement is significant. Suppose, however, that one of these
piles has the pages lying in numerical order from page 1 to page 100. As a
distribution of paper, and assuming similar operative factors, this stack is no
more or less likely than any other; but considered as a significant (numerical)
ordering – which it certainly is – it invites an explanation which the others do
not. For while the probability of its occurring is as before, the probability of
some or other non-significant ordering (i.e. any other than it) is 3,628,799.
That is to say, while your chance of stacking them in sequence is 0.00002756
per cent, the chances of doing otherwise are 99.99997244 per cent.
Admittedly, it remains possible that the significantly ordered stacking is
the result of chance; but that hypothesis is much more implausible than one
which invokes a different causal ancestry, hypothesizing that the seemingly
random shuffling was in fact a well-controlled manipulation designed to order
the pages sequentially. Where an explanation is available that renders an
improbable outcome more likely one should prefer it to an explanation that
preserves the improbability, and the greater the differential the more one
should favour the probabilizing hypothesis. I do not know what the prob-
abilities in question are, but on the assumption that the range of possible
universes is very large, if not infinite, the chances of any particular outcome
are small and diminish as that outcome moves up the scale of significant
ordering. Equivalently, the occurrence of ‘harmonious’ arrangements is less
likely than that of ‘discordant’ ones. The evidence of fine tuning is precisely
of this sort. For example, if it is accurate, it tells us that a tiny percentage of
possible universes having structurally equivalent laws to our own, but varying
in respect of fundamental ratios and quantities, are life permitting. The fact
that one such exists (that it is ours is only relevant to the extent that it allows
us to contemplate the issue) calls for explanation. The hypothesis that this
fact is not the outcome of chance renders it far less unlikely than does the