Snarks: I disagree. Attributing to mathematics the characteristics commonly attributed to a deity makes little sense to me.
The original article is online here. A more current view of the phenomenon by Cumrum Vafa is here.
My personal favorite example is Riemannian geometry which Einstein was able to pull off the shelf to describe general relativity.
Barrows observation is that mathematics exists, the mathematician or geometer comes along and discovers it. Pi is true everywhere in space/time. And because it transcends the human creative process, it has a mystical quality or as Wigner and Vafa observe, it is unreasonably effective.
In my view, the unreasonable effectiveness of math - like the fact of a beginning and that the universe is intelligible at all - declares that God exists. Order cannot rise out of chaos in an unguided physical system.
There are a bunch of convective cells off the coast of Africa and next thing you know there's a hurricane. So the Coriolis effect is "guidance"?