Back in the 1800s, there was a philosophical argument against any
activity by "God", based on the idea that the universe was
deterministic and causal, like a big mechanical clock, and so there was no room for God to act.
God may have started the clock, but He can't mess with it now, because
that would have to violate causality (and break the clock).
I've recently (2007) heard biologists on television arguing along these
lines re: evolution. God couldn't have been involved in how evolution
turned out, because it's all mechanical and causal. Whatever happened
was predetermined by the mechanisms involved.
Given what we know about quantum mechanics, chaotic systems, and
comets at this point, this argument seems just absurd from a modern
scientific point of view:
None of this means there has to be a God, scientifically, but it makes
the clockwork universe argument ridiculous (especially regarding evolution).