Does "given a fair wind" mean "given a proper power"?

Context:

On this model we should expect that, in different geographical
regions, different arbitrary beliefs, none of which have any factual
basis, will be handed down, to be believed with the same conviction
as useful pieces of traditional wisdom such as the belief that manure
is good for the crops. We should also expect that superstitions and
other non-factual beliefs will locally evolve - change over gener-
ations - either by random drift or by some sort of analogue of
Darwinian selection, eventually showing a pattern of significant
divergence from common ancestry. Languages drift apart from a
common progenitor given sufficient time in geographical separation
(I shall return to this point in a moment). The same seems to be true
of baseless and arbitrary beliefs and injunctions, handed down
the generations - beliefs that were perhaps given a fair wind by the
useful programmability of the child brain.