Dr. Michio Kaku — Exploring Time Travel, the Beauty of Physics, and More | The Tim Ferriss Show

He recounts seeing a newspaper photo of Einstein’s desk with the claim that Einstein “could not finish this book,” which pushed him to the library and into a long-term fascination with a “theory of everything.” He describes later pursuing this goal through building an “atom smasher” in high school and aiming his career at unified field theory/string theory.

He says many questions (e.g., what happened before the Big Bang, what’s inside black holes, whether time travel is possible) are where Einstein’s equations and the standard model “break down,” and he positions string theory as the framework meant to address that boundary. He also describes the “God equation” as a compact description of nature’s laws, echoing Einstein’s ambition.

He argues time travel went from being something physicists would “giggle” at to something taken seriously after many solutions to Einstein’s equations were found that allow it, including the Gödel solution and other scenarios involving rotation and black holes. He cites Stephen Hawking’s “chronology protection hypothesis” as a challenge to find a law forbidding time travel, and says no such definitive law has been found so far.

He defines a parallel universe using an analogy of two sheets of paper connected by a pencil as a “wormhole,” and credits Einstein (1935) with early mathematical work on such connections. He describes wormholes as potential gateways to another universe, a distant point in our universe, or possibly the past—while emphasizing such travel would require technology far beyond current capability.

He offers a specific definition: consciousness is “the sum total of all the feedback loops” needed to create a model of yourself in space, time, and society; he extends this across systems from thermostats to plants to reptiles to humans. He argues human consciousness is distinguished by the ability to model the self in time—daydreaming and projecting into the future—and suggests a practical test is whether you can teach a dog “tomorrow.”