I suppose you could form a hypothesis and conduct and experiment that, if the hypothesis is correct, would cause something "miraculous" (i.e. statistically impossible) to happen in the present...
Like, if I forgot my keys, and then decided that, when I eventually find my keys, I'll go back in time and put them under this rock, and then WHOA my keys are under the rock!! (Now to remember to do that, so the universe doesn't fall apart...)
