In the Beatles’ song Maxwell’s Silver Hammer, the lyrics feature Maxwell Edison and the Silver Hammer he brings down. This single, utterly ordinary “silver hammer”—something trivial compared with the scale of unexpected events and their consequences—ends up smashing rules and conventions that people have spent years building. As Paul McCartney described it, it represents “a symbol of the absurdity of life.” The song comically portrays how major incidents can unfold in a matter‑of‑fact way, simply as the result of natural circumstances. People’s assumptions and preconceptions create situations where, with just a slight shift in perspective, it’s never surprising that the Silver Hammer might come crashing down at any moment.

In the world of physics, there are many unknown “silver hammers,” and one of the most prominent examples is Einstein’s theory of relativity. Because Einstein handled the constancy of the speed of light through mental calculation, he constructed his theory without explicitly writing down the crucial unknown function. As a result, in order to preserve the constancy of light speed, he placed that unknown function in the wrong place—one that effectively distorts time and space. The theory of relativity, which overturned the foundations of classical physics and even reshaped our understanding of spacetime and the universe, will continue to act as a Silver Hammer, brought down upon modern physics by that single act of mental arithmetic.

With just a slight shift in perspective, you can uncover Silver Hammers—ideas capable of overturning the foundations of physics—with surprising ease. And now, Maxwell is here to introduce one of those eye‑opening Silver Hammers.