I’m currently reading Exhalation by Ted Chiang. I’ll write a more detailed impression of the book after I’ve finished it, but I need to share this little anecdote. The first story in the book, “The Merchant and the Alchemist’s Gate” deals with the mind-bending concept of an alchemist’s gate which allows a person to travel 20 years into the future by passing through one side and travel 20 years into the past by passing through the other side. There are no Back to the Future rules here. You can say hello to your past or future self. You can interact with them in any way you’d like. No problem. As long as the gate is available, you can pass back through to your time.
You cannot alter the past or change the future. You can only observe it in greater detail. When you look at your past or future in greater detail, you might witness the fact that you’ve already traveled back and altered the past and the present you lived was a precursor to you traveling back to the past…and…Ted Chiang somehow makes this madness work.
I read “The Merchant and the Alchemist’s Gate” late at night and napped a bit on the couch, and holy crap, my brain was in overdrive trying to figure out the weird time travel logic seeds Ted Chiang had sewn. Talk about strange dreams! What an absolute master!