--- title: "Meaning & Key Takeaway of: Einstein recalled realizing that a person…" description: "\"“Einstein recalled realizing that a person falling from the roof of a building would feel no effects of gravity as he fell. He called this \"the most fo..." image: "https://sms4smile.com/quotes/i/b46/lee-smolin-4171_gravity_einstein-recalled-realizing-that-a-perso_874600.jpg" --- # Einstein recalled realizing that a person falling from the… ![“Einstein recalled realizing that a person falling from the roof of a building would feel no effects of gravity as he fell. He called this "the most fortunate thought of my life," and he made it into a principle, which he called the principle of equivalence. It says that the effects of acceleration…” quote by Lee Smolin](https://sms4smile.com/quotes/i/b46/lee-smolin-4171_gravity_einstein-recalled-realizing-that-a-perso_874600.jpg) [Download](https://sms4smile.com/quotes/i/b46/lee-smolin-4171_gravity_einstein-recalled-realizing-that-a-perso_874600.jpg) [Open image](https://sms4smile.com/quotes/i/b46/lee-smolin-4171_gravity_einstein-recalled-realizing-that-a-perso_874600.jpg) > ““Einstein recalled realizing that a person falling from the roof of a building would feel no effects of gravity as he fell. He called this "the most fortunate thought of my life," and he made it into a principle, which he called the principle of equivalence. It says that the effects of acceleration are indistinguishable from the effects of gravity. So Einstein succeeded in unifying all kinds of motion. Uniform motion is indistinguishable from rest. And acceleration is no different from being at rest but with a gravitational field turned on.”” [Lee Smolin](https://sms4smile.com/quotes/author/lee-smolin/) ## About This Quote This interpretation was drafted with AI assistance. It is one reading of the quote, not the author's own explanation. Einstein realized that free fall feels weightless, leading to the principle that acceleration and gravity are indistinguishable, unifying motion concepts. **In simple terms:** Free fall feels weightless, linking acceleration and gravity. Key Takeaway Recognize that inertial and gravitational effects are equivalent. Themes physics relativity inertia gravity unification Mood curious inquisitive Type scientific philosophical When to use this quote - falling in an elevator - spacecraft launch - accelerated lab experiments - educational demonstrations Key Concepts Equivalence principle general relativity inertial frames Questions to Reflect On - How does this principle change our view of gravity? - What limits does it have in strong fields? A Different Perspective The principle applies only locally; tidal forces reveal differences. ★ ★ ★ ★ ★ No ratings yet [Gravity](https://sms4smile.com/quotes/about/gravity/) ## Related quotes > [“By the time I began my study of physics in the early 1970s, the idea of unifying gravity with the other forces was as…](https://sms4smile.com/quotes/lee-smolin/by-the-time-i-began-my-study-of-physics-in-the-early-1970s-the-idea/) [Lee Smolin](https://sms4smile.com/quotes/author/lee-smolin/) > [Every string theory that's been written down says the speed of light is universal. 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