I was once told all of calculus, and by extension all of mathematics, was built upon an assumption, and that should this assumption prove false, everything we know about mathematics, physics, the world as a whole would just crumble into nothingness and we would be left to flounder in a world of unknown possibilities and frightening realizations.
The truth is that was all before I became a math major and learned this is just a staple fact of axiomatic math: We make initial assumptions, build systems upon them, but acknowledge that they only hold when those foundational axioms are true. (That’s why there’s multiple geometries–such as Euclidean and hyperbolic, etc.) So the world won’t come crashing down in fire and brimstone. We just know the rules won’t always apply.
The point of any of this is not at all mathematical–but factual. Like Tolkien posited, a reader will only believe so long as the writer has sufficiently sowed a willing suspension of disbelief in the reader–the notion that, for a moment, we will ignore the rules we know in favor of the rules we wish to believe. For a brief few moments, dashing from word to word across the page, we forget that reality has bounds and for a moment become limitless.
I’ve lived my own life as both reader and writer: I’ve laid a foundation of beliefs upon basic axiomatic assumptions, and as I write these words, I fear I’m losing hold of my own willing suspension of disbelief.