What would happen if physicists thought more like engineers or designers?

That’s part of what Michael Nielsen asks in this mind-bending essay:

Now we understand the fundamentals of how matter works: we have a fantastic theory describing the elementary particles and forces, and we’re getting increasingly good at manipulating matter. And so we’re beginning to ask: what can we build, in principle? Not just in a practical sense, with the tools that happen to be at hand, but in a fundamental sense: what is allowed by the laws of physics?

Nielsen has form to think about this. As one of the pioneers of quantum computing, he spent his early career constructing a new discipline by imagining the possibilities latent in cutting-edge physics.

Now he’s zooming out and trying to grapple with the general case. What is the total space of things that could exist, in conformity with the physical rules of the universe? How can we explore that space, unconstrained by the detail of whether something similar actually exists on earth?

And, on the way there, how can we even think about that question? Physics is stereotypically a discipline of discovery, not of invention. Could it take some invention tips from programming, from design, from engineering, even from mathematics?

Nielsen has a lot more to say here. He’s charging straight for the big, big questions, and scoping out a project worthy of being a life’s work, or ending up institutionalized as a new university department somewhere.