Short answers, pulled from the story.
Lee Smolin is best known for his contributions to loop quantum gravity, a theory that attempts to unify quantum mechanics with general relativity by treating space itself as discrete at the smallest scales. He also proposed cosmological natural selection, the hypothesis that universes reproduce through black holes, and wrote The Trouble with Physics, a widely read critique of string theory published in 2006.
Cosmological natural selection, also called the fecund universes theory, proposes that collapsing black holes give rise to new universes whose fundamental constants may differ slightly from the parent universe. Universes with more black holes leave more offspring, so over many generations the population is dominated by universes like our own. Smolin published the idea in 1992 and developed it further in his 1997 book The Life of the Cosmos.
The Trouble with Physics, published in 2006, argued that string theory had gained an unhealthy near-monopoly in particle physics without producing experimentally testable predictions, and that its use of the anthropic principle to explain our universe's properties placed it outside the reach of experimental test. Smolin called for diverse competing research programs and greater attention to loop quantum gravity.
Smolin argues that time is the most fundamental feature of reality and that physical science has wrongly treated it as unreal. In his 2013 book Time Reborn, he wrote that space may be an illusion but time must be real. He also holds that nothing exists timelessly, everything real is a process leading to the next moment, and the laws of physics may themselves evolve.
Loop quantum gravity is an approach to unifying quantum mechanics and general relativity that reformulates general relativity in the language of gauge field theories, expressing fields as the dynamics of loops. Smolin contributed to the theory in collaboration with Ted Jacobson, Carlo Rovelli, Louis Crane, Abhay Ashtekar, and others. With Rovelli, he discovered that areas and volumes in this framework are discrete, finding their natural expression in terms of spin networks.
In 2026, Smolin agreed to pause his relationship with the Perimeter Institute for Theoretical Physics following revelations that he had maintained contact with Jeffrey Epstein after Epstein's initial conviction. Documents released in 2025 and 2026 showed contact as recently as 2013, including an invitation to the US Virgin Islands in 2011, contradicting Smolin's 2019 statement that he had not been in contact with Epstein since 2008.