You may have heard this quote before, or something very much like it.  It comes from nuclear physicist Ernest Rutherford (1871-1937), who said, “If you can’t explain your physics to a barmaid it is probably not very good physics.”

With that sentiment in mind, today I’d like to share another quote from the recent hit Sci-Fi novel The Three Body Problem by Cixin Liu. I don’t think I’ve ever seen the difficulties of modern physics summed up so succinctly anywhere else:

Modern theoretical models have become more and more complex, vague, and uncertain. Experimental verification has become more difficult as well.  This is a sign that the forefront of physics research seems to be hitting a wall.

In other words, modern physics has become so weird and convoluted that hardly anyone (barmaid or otherwise) can understand it.  And that means something is very wrong with modern physics.

Personally, I tend to avoid high-level physics.  Part of the reason is that, as a science fiction writer, I’m more concerned with the everyday experiences my characters have to deal with.  What’s it really like to walk around on Mars?  What sorts of gases might my non-human characters be able to breathe? What could go wrong if some hotshot space pilot tried to fly through the rings of Saturn?

But another part of it is that a lot of high-level theoretical physics stuff—things like string theory, supersymmetry, the multiverse—does sound vague and uncertain.  It feels more like guesswork than science.  Admittedly, the best guesses of a theoretical physicist are built on a firmer foundation that anything I might think up.  But still, for the purposes of science fiction, I feel like I have more leeway to make stuff up with high-level physics than I do with “ordinary” physics like the rocket equation.

I’ve heard physicists sometimes joke that someone—time travelers, aliens, God, the universe itself—is deliberately messing with us.  Maybe that’s why our latest high-tech physics experiments keep producing such confusing results. Maybe that’s why we have to keep resorting to such vague and uncertain theories to explain our discoveries.

And minor spoiler: The Three Body Problem sort of takes that joke and runs with it.  But in all seriousness, the forefront of physics does seem to have hit a wall.  At least that’s my impression, and I loved how Cixin Liu summed that feeling up in just three quick lines.