Halfway through writing my response to Andukar, I noticed the appearance of Anark's writeup, which says most of what I was thinking, and more clearly than I could have put it.
I'd have to disagree with Andukar's statement "it is math nonetheless". Mathematics
and physics describe the world, but they aren't actually the world.
Take as an example an equation describing the y-component of projectile motion in two
dimensions:
vy = v0 sin θ + ayt
If someone were to fire a
projectile, its motion will, in fact, be precisely
predicted by
that equation.
1 But is the projectile actually
using the equation to
move? Is the
universe itself actually
running numbers through equations to determine what
it will do next? Clearly not, as this would require an endless stack of places-to-run-the-numbers, which themselves would have to operate on such rules. (cf.
Douglas Hofstadter)
The equations describe the events of the universe; they do not specify
the events.
1With the usual caveats about air resistance, relativistic speeds, external
forces, etc., which are not relevant to the discussion.