The Mustache Effect

It's a pleasant day for a drive.

Very much so. I love the Austrian countryside in May.

But these old cars didn't really have anything like a 'suspension,' did they?

No, not really. A shame, since the roads weren't paved.

And the horse carts. We have to dodge horse carts, there's real rhyme or reason for the traffic. People driving wherever they want to. I think I'd prefer it if you drive.

Linz is just ahead. We can lunch and gas up there. I'll drive us the rest of the way.

Oh, thank you. Look at the insects on the windshield. It's getting hard to see through them. Do you think that it's true, if you go back in time and squash a bug, the entire history of humanity could change...

Oh no, not really. That's just a purposeful misinterpretation of mathematics used as a plot device for science fiction stories. I've been going on these missions for ten years, and there's never been any noticeable effect.

But if history changed, would you notice?

Very astute question. Probably not. All history would change, including mine. And so would my memories.

So you can't reassure me that these bugs won't erase my Aunt Emma, cause her to never have been born?

Ah, but you have reassured me! Since whatever we do, we won't notice it, no one will notice it, then there are no consequences. Our existence is as morally neutral here as it is if we'd gone to the cafeteria for lunch.

But aren't there moral consequences? What if that bee there was to pollinate a field, and now there will be a famine in pre-war Austria?

Those would be the same consequences you have every day when you drive your car or even ride your bike. I know when I go for a run by the stream in the mornings, I sometimes cough up insects that I had no idea I was breathing.

That's gross.

But true. The moral consequences of time travel are no different than the moral consequences living a life. Purely consequential, some positive, some negative, all unknown. And, hopefully, at least balancing out. I mean you do believe that what we're doing is good for humanity, don't you.

Yes, of course, but I'm just worried... Crap, what did I hit?

A man. You look over the car, and I'll go see if he's alright.

Well, I think everything about he car looks okay. How is the guy I ran over.

Well, remember how you were worried about maybe changing history?

Yes. Oh, no. No. No.

I think you just ran over Adolf Hitler.