HELGOLAND

The theoretical physicist and bestselling author digs into his discipline’s most confounding concept.

As lucidly as he can, Rovelli shows that while quantum theory may clarify the foundations of science, it doesn’t make sense. “Its mathematics does not describe reality,” he writes. “Distant objects seem magically connected. Matter is replaced by ghostly waves of probability.” And yet, it “has never been found wrong.” The author begins with the easy part: the history. Helgoland is a barren island in the North Sea where, in 1925, a young Werner Heisenberg spent the summer trying to explain how electrons behave. The 20-year-old explanation that atoms consisted of tiny electrons whirling around heavier protons—as planets orbit the sun—didn’t work. Electrons don’t whirl like specks of matter but rather in diffuse, cloudlike waves. However, whenever scientists deal with an electron (such as in a particle accelerator), it becomes a speck of matter. After much agonizing, Heisenberg decided not to explain electron behavior but simply describe what happens. The result was a brilliant, if clunky, formulation using mathematical matrixes that correctly predicted what experiments showed. Within a few years, other geniuses (Schrödinger, Pauli, Dirac, Born) refined and simplified Heisenberg’s work, and quantum theory was off and running. After 100 years, scientists still agree that quantum theory remains an enigma, but it works so well that only a persistent minority, Rovelli included, try to make sense of it. In the book’s second half, more philosophy than science, the author maintains that every entity in the universe, from protons to humans, exists only in relation to other objects. Something that didn’t interact would be invisible. Expressing doubt over Ernst Mach’s insistence that science must be based on the “observable,” Rovelli leans toward the Buddhist teaching that “there is nothing that exists in itself, independently from something else.”

Often heavy going, but a thoughtful argument that “all nature is quantum” and that we should go with the flow.