Get Off The Premises

Aaron Hillis's thumbs up review of Source Code in the Village Voice has this complaint:

Like every time-travel yarn (though, technically, the time-loop logic here has more in common with Groundhog Day than 12 Monkeys), there are far-fetched plot wrinkles and quickly reeled-off quantum claptrap to distract us from the impossibilities, so let’s try suspending our disbelief in favor of a salvaged consciousness kept alive and “time reassignment.” Just as our brains fill in the periphery of our vision with a seamless blur of what we think exists, Colter’s choose-his-own-adventure courses of action should be limited to the last sensory experiences of the dead man he inhabits. Never-before-had conversations between characters make for enticing drama, but how the hell can our man peer into heating ducts or even get off the train to notice MacGuffins that weren’t discovered in the real-time wreckage?

This is always a tricky thing in sf and fantasy--how much to accept.  If you don't give them the premise, there's no story. But how far can they go before you object? Hillis will go along with the nonsense that allows someone to go back into the last eight minutes of another person's life, but won't allow the quantum magic that has our hero act differently from how the person he's using originally did. Seems to me that's part of the premise--you have to buy it or you might as well not get on the train.

When a story is set in the real world, we have enough experience to understand how things are likely to go.  Fantasy is allowed to change the rules--though this often weakens its power.  A guy trying to shoot a bear before it kills him automatically means something, even if you've never gone hunting.  But shooting an imaginary beast with an imaginary gun on an imaginary planet only means something if the creator has made us invest something in the story already.

Yet different people have different quibbles over what's believable in stories where science is indistinguishable from magic.  I recall Siskel and Ebert complaining about the speeder bike chase through the forest of Endor in Return Of The Jedi. "Why don't they fly above the trees?" they asked.  Well, maybe the speeder bikes don't move vertically that well.  Maybe it was a way of getting away from people chasing you.  Maybe the branches and leaves are too thick to allow it.  Maybe the air on the moon of Endor gets very thin a few hundred feet up so repulsorlift engines don't work.  Maybe a hundred other reasons.  Yet this is where Siskel and Ebert decided to take a stand--apparently they're experts on the physics of speeder bikes, the flora of Endor and the psychology of Imperial Stormtroopers.