One of the weirdest aspects of quantum mechanisms is entanglement, because two entangled particles affecting each other across vast distances seems to violate a fundamental principle of physics called locality: things that happen at a particular point in space can only influence the points closest to it. But what if locality — and space itself — is not so fundamental after all? Author George Musser explores the implications in his new book, Spooky Action at a Distance.
When we think in terms of such a level, the connections between subatomic particles across a lab bench, between the inside and the outside of a black hole, and between opposite sides of the universe don’t seem so spooky anymore. Michael Heller, a physicist, philosopher, and priest at the Pontifical Academy of Theology in Krakow, Poland, says: “If you agree that the fundamental level of physics is not local, everything is natural, because these two particles which are far apart from each other explore the same fundamental nonlocal level. For them, time and space don’t matter.” Only when you try to visualise these phenomena in terms of space — which is forgivable, because it’s hard for us to think in any other way — do they defy comprehension.
The idea of a deeper level seems natural because, after all, it is what physicists have always sought. Whenever they can’t fathom some aspect of our world, they assume they must not yet have gotten to the bottom of it all. They zoom in and look for the building blocks. How mysterious it is, for example, that liquid water can boil to steam or freeze to ice. Yet these transformations make perfect sense if liquid, vapour and solid are not elemental substances, but distinct forms of a single fundamental substance.
“Spacetime can’t be fundamental,” says the theorist Nima Arkani-Hamed. “It has to come out of something more basic.”
This thinking completely inverts physics. Nonlocality is no longer the mystery; it’s the way things really are, and locality becomes the puzzle. When we can no longer take space for granted, we have to explain what it is and how it arises, either on its own or in union with time.
When it comes to space, though, there can be no “smaller,” because size itself is a spatial concept. The building blocks cannot presume space if they are to explain it. They must have neither size nor location; they are everywhere, spanning the entire universe, and nowhere, impossible to point to. What would it mean for things not to have positions? Where would they be? “When we talk about emergent space-time, it must come out of some framework that is very far from what we’re familiar with,” Arkani-Hamed says.
Within Western philosophy, the realm beyond space has traditionally been considered a realm beyond physics — the plane of God’s existence in Christian theology. In the early eighteenth century, Gottfried Leibniz’s “monads” — which he imagined to be the primitive elements of the universe — existed, like God, outside space and time. His theory was a step toward emergent space-time, but it was still metaphysical, with only a vague connection to the world of concrete things. If physicists are to succeed in explaining space as emergent, they must adapt the concept of spacelessness as one of their own.