No, I remind myself, I'm hallucinating that I'm naked and strapped to a gurney. Because none of this is real. (2.45)
We can't blame Jason for being confused initially, as we ourselves don't know how we'd handle things if we woke up one day and everything in our lives was completely different. How do you think you would react?
Or—is it more plausible that a tumor in my brain has turned my world upside down? (3.133)
At first, Jason is convinced that his confusion about the nature of reality is based on some sort of traumatic brain injury. That, oddly enough, is a fairly logical explanation. And it turns out to be nowhere near as crazy as the truth.
"We all live day to day completely oblivious to the fact that we're a part of a much larger and stranger reality than we can possibly imagine." (5.459)
Ain't that the truth. Although Jason has always known all of this intellectually, we doubt he understood the full extent of it until he stood face-to-face with the infinite span of the multiverse. That kind of thing tends to really expand your brain.
This is not my world.
Even as those five words cross my mind, I'm not exactly certain what they mean, or how to begin to consider their full weight. (5.596)
Which do you think would be harder to grasp: that you're hallucinating a completely different reality from your own, or that you're literally in a parallel universe? Both options are pretty trippy. This realization threatens to completely upend Jason's view of what's real and what's not.
I should be opening more doors, but the truth is I'm terrified. I've lost faith we'll find a world that's safe. (8.361)
The first few "realities" Jason visits are terrifying. There's Apocalyptic Chicago. There's Ice-Age Chicago. There's Plague-Ridden Chicago. And although Jason knows that these universes aren't his home, they still affect him profoundly—and technically, each of these universes is every bit as real as his home universe.
In the distance, that fantastical skyline inches closer. The buildings don't even make sense. (10.45)
Futuristic Chicago is one of the few parallel universes that isn't completely terrifying. We're going to count that as a win. What's more, it shows just how different these infinite worlds can be.
"All I wrote was, 'I want to go home.'"
"Exactly. That's what you wrote, but you carried baggage through the door." (10.579)
This is a big revelation. Not only can Jason and Amanda define the reality they enter by means of their thoughts, but that reality is also further shaped by their emotional state. Think of the infinite possibilities that set-up creates.
If there are infinite worlds, how do I find the one that is uniquely, specifically mine? (10.608)
That's the million-dollar question. As it turns out, Jason finds his own universe by focusing on the one thing that defines his place in his universe more than anything else: his love for Daniela. That's a big deal: it means that love is the realest thing in the multiverse.
[The theory of uncanny valley] holds that when something looks almost like a human being [...] it creates revulsion in the observer. (11.2-3)
Jason is a whole lot more disconcerted when he visits universes that are similar to his own than he is when they're wildly different. It makes sense when you think about it. If the Chicago he visits is a frozen wasteland or futuristic cityscape, then it's pretty easy for him to distinguish that Chicago from the one in his own reality. But when it isn't? That's a lot more mind-bending.
Feels like I've been traveling in the box for years.
I don't know how many Chicagos we've connected to so far.
They're all beginning to blend. (11.200-202)
At a certain point, Jason starts to go a little cray. We can't blame him: we know our minds would have exploded the first time we stepped out of the box and into a parallel universe. Our brains aren't equipped for such an expansive view of reality. That's an interesting point: it means that the ultimate reality is simply beyond our comprehension. We can understand aspects of it—like, we know what a hallway full of doors is like—but when it comes down to it, we have to remember that there's a certain limit to what we can absolutely know about the universe—and about ourselves.