--- title: "Meaning & Key Takeaway of: Which of the two possibilities…" description: "\"“Which of the two possibilities corresponds to reality is simply unknown until a definite measurement is made, at which point the quantum state instant..." image: "https://sms4smile.com/quotes/i/b22/leon-m-lederman-20865_quantum_which-of-the-two-possibilities-correspon_2839036.jpg" --- # Which of the two possibilities corresponds to reality is… ![“Which of the two possibilities corresponds to reality is simply unknown until a definite measurement is made, at which point the quantum state instantaneously changes to reflect the result of that measurement.” quote by Leon M. Lederman](https://sms4smile.com/quotes/i/b22/leon-m-lederman-20865_quantum_which-of-the-two-possibilities-correspon_2839036.jpg) [Download](https://sms4smile.com/quotes/i/b22/leon-m-lederman-20865_quantum_which-of-the-two-possibilities-correspon_2839036.jpg) [Open image](https://sms4smile.com/quotes/i/b22/leon-m-lederman-20865_quantum_which-of-the-two-possibilities-correspon_2839036.jpg) > ““Which of the two possibilities corresponds to reality is simply unknown until a definite measurement is made, at which point the quantum state instantaneously changes to reflect the result of that measurement.”” [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) ## About This Quote This interpretation was drafted with AI assistance. It is one reading of the quote, not the author's own explanation. Reality is undetermined until measured; measurement forces the quantum state to update instantly to the observed outcome. **In simple terms:** Measurement decides reality. Key Takeaway Accept uncertainty, observe to know. Themes physics uncertainty measurement Mood curious thoughtful Type scientific philosophical When to use this quote - lab experiments - particle detection - philosophical debates Key Concepts quantum mechanics wavefunction collapse Questions to Reflect On - How does observation shape reality? - Can we ever know a system without influencing it? A Different Perspective Measurement may be limited by observer effect. ★ ★ ★ ★ ★ No ratings yet [Corresponds Reality](https://sms4smile.com/quotes/about/corresponds-reality-3712040/) [Definite Measurement](https://sms4smile.com/quotes/about/definite-measurement-3712041/) [Point Quantum](https://sms4smile.com/quotes/about/point-quantum-3712042/) [Quantum](https://sms4smile.com/quotes/about/quantum/) [Quantum State](https://sms4smile.com/quotes/about/quantum-state-3385138/) [Theory](https://sms4smile.com/quotes/about/theory/) ## Related quotes > [Faith is not so much a binary pole as a quantum state, which tends to indeterminacy when closely examined.](https://sms4smile.com/quotes/john-updike/faith-is-not-so-much-a-binary-pole-as-a-quantum-state-which-tends-to/) [John Updike](https://sms4smile.com/quotes/author/john-updike/) > [If what we regard as real depends on our theory, how can we make reality the basis of our philosophy? ...But we cannot distinguish…](https://sms4smile.com/quotes/stephen-hawking/if-what-we-regard-as-real-depends-on-our-theory-how-can-we-make/) [Stephen Hawking](https://sms4smile.com/quotes/author/stephen-hawking/) > [“Quantum mechanics, for example, shows us that we are not as separate from the rest of the world as we once thought. 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Hogan](https://sms4smile.com/quotes/author/james-p-hogan/) > [A popular feel for scientific endeavors should, if possible, be restored given the needs of the twenty-first century. This does not mean that every…](https://sms4smile.com/quotes/walter-isaacson/a-popular-feel-for-scientific-endeavors-should-if-possible-be/) [Walter Isaacson](https://sms4smile.com/quotes/author/walter-isaacson/) > [“in experimental quantum mechanics we have run right up against what was previously perceived to be a purely philosophical barrier. 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It is the transition from understanding quantum reality…](https://sms4smile.com/quotes/ludmila-morozova-buss/quantum-technology-is-no-longer-theoretical-the-quantum-revolution-is/) [Ludmila Morozova-Buss](https://sms4smile.com/quotes/author/ludmila-morozova-buss/) > [Quantum physics fluctuates all the time. But now the fluctuations are not just particles coming into and out of existence, which happens all the…](https://sms4smile.com/quotes/neil-degrasse-tyson/quantum-physics-fluctuates-all-the-time-but-now-the-fluctuations-are/) [Neil deGrasse Tyson](https://sms4smile.com/quotes/author/neil-degrasse-tyson/) ## More by Leon M. Lederman > [ He \[Democritus\] is probably best known for two of the most scientifically intuitive quotes ever uttered by an ancient: 'Nothing exists except atoms and… ](https://sms4smile.com/quotes/leon-m-lederman/he-democritus-is-probably-best-known-for-two-of-the-most/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [By the grace of AEC, BNL, God, Green and Hayworth (alphabetical order), we should see neutrinos.](https://sms4smile.com/quotes/leon-m-lederman/by-the-grace-of-aec-bnl-god-green-and-hayworth-alphabetical-order-we/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [Theorists write all the popular books on science: Heinz Pagels, Frank Wilczek, Stephen Hawking, Richard Feynman, et al. And why not? They have all…](https://sms4smile.com/quotes/leon-m-lederman/theorists-write-all-the-popular-books-on-science-heinz-pagels-frank/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [Particle physics suffers more from being infected by the socio-political mood of the day than from lack of spectacular opportunities for major and profound…](https://sms4smile.com/quotes/leon-m-lederman/particle-physics-suffers-more-from-being-infected-by-the-socio/) [Leon M. 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Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [The history of atomism is one of reductionism – the effort to reduce all the operations of nature to a small number of laws…](https://sms4smile.com/quotes/leon-m-lederman/the-history-of-atomism-is-one-of-reductionism-the-effort-to-reduce/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [My children have often asked me why I never received a Nobel Prize. I used to tell them it was because the Nobel committee…](https://sms4smile.com/quotes/leon-m-lederman/my-children-have-often-asked-me-why-i-never-received-a-nobel-prize-i/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [During an intense period of lab work, the outside world vanishes and the obsession is total. Sleep is when you can curl up on…](https://sms4smile.com/quotes/leon-m-lederman/during-an-intense-period-of-lab-work-the-outside-world-vanishes-and/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [The aether: Invented by Isaac Newton, reinvented by James Clerk Maxwell. This is the stuff that fills up the empty space of the universe.…](https://sms4smile.com/quotes/leon-m-lederman/the-aether-invented-by-isaac-newton-reinvented-by-james-clerk-maxwell/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [Experimenters don’t come in late—they never went home.](https://sms4smile.com/quotes/leon-m-lederman/experimenters-don-t-come-in-late-they-never-went-home/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [I started out as a molecules kid. In high school and early college I loved chemistry, but I gradually shifted toward physics, which seemed…](https://sms4smile.com/quotes/leon-m-lederman/i-started-out-as-a-molecules-kid-in-high-school-and-early-college-i/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [I'm so old I can remember when the Dead Sea was only sick.](https://sms4smile.com/quotes/leon-m-lederman/i-m-so-old-i-can-remember-when-the-dead-sea-was-only-sick/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) > [ Where do we stand today compared to Greece circa 400 B.C.? Today's experiment-driven 'standard model' is not all that dissimilar to Democritus's speculative \[sic\]… ](https://sms4smile.com/quotes/leon-m-lederman/where-do-we-stand-today-compared-to-greece-circa-400-b-c-today-s/) [Leon M. Lederman](https://sms4smile.com/quotes/author/leon-m-lederman/) [Explore all 30 Leon M. Lederman quotes ](https://sms4smile.com/quotes/author/leon-m-lederman/) ## More Quantum quotes > [Quantum physics fluctuates all the time. But now the fluctuations are not just particles coming into and out of existence, which happens all the…](https://sms4smile.com/quotes/neil-degrasse-tyson/quantum-physics-fluctuates-all-the-time-but-now-the-fluctuations-are/) [Neil deGrasse Tyson](https://sms4smile.com/quotes/author/neil-degrasse-tyson/) > [“Quantum Technology Is No Longer Theoretical The quantum revolution is not the discovery of quantum physics. It is the transition from understanding quantum reality…](https://sms4smile.com/quotes/ludmila-morozova-buss/quantum-technology-is-no-longer-theoretical-the-quantum-revolution-is/) [Ludmila Morozova-Buss](https://sms4smile.com/quotes/author/ludmila-morozova-buss/) > [Courageous dreaming allows you to create from the source, the quantum soup of the universe where everything exists in a latent or potential state.](https://sms4smile.com/quotes/alberto-villoldo/courageous-dreaming-allows-you-to-create-from-the-source-the-quantum/) [Alberto Villoldo](https://sms4smile.com/quotes/author/alberto-villoldo/) > [Trying to understand the way nature works involves a most terrible test of human reasoning ability. It involves subtle trickery, beautiful tightropes of logic…](https://sms4smile.com/quotes/richard-p-feynman/trying-to-understand-the-way-nature-works-involves-a-most-terrible/) [Richard P. Feynman](https://sms4smile.com/quotes/author/richard-p-feynman/) > [We are thankful for good-will rather than for services, for the motive than the quantum of favor received.](https://sms4smile.com/quotes/william-hazlitt/we-are-thankful-for-good-will-rather-than-for-services-for-the-motive/) [William Hazlitt](https://sms4smile.com/quotes/author/william-hazlitt/) > [We are the product of quantum fluctuations in the very early universe.](https://sms4smile.com/quotes/stephen-hawking/we-are-the-product-of-quantum-fluctuations-in-the-very-early-universe/) [Stephen Hawking](https://sms4smile.com/quotes/author/stephen-hawking/) > [“All creativity is based on quantum leaps and uncertainty.”](https://sms4smile.com/quotes/deepak-chopra/all-creativity-is-based-on-quantum-leaps-and-uncertainty/) [Deepak Chopra](https://sms4smile.com/quotes/author/deepak-chopra/) > [After 'Quantum Leap,' a lot of sci-fi things came my way, and I had to say, 'I can't do that right now.'](https://sms4smile.com/quotes/scott-bakula/after-quantum-leap-a-lot-of-sci-fi-things-came-my-way-and-i-had-to/) [Scott Bakula](https://sms4smile.com/quotes/author/scott-bakula/) > [“The world of quantum mechanics is not a world of objects: it is a world of events.”](https://sms4smile.com/quotes/carlo-rovelli/the-world-of-quantum-mechanics-is-not-a-world-of-objects-it-is-a/) [Carlo Rovelli](https://sms4smile.com/quotes/author/carlo-rovelli/) > [It would take a civilization far more advanced than ours, unbelievably advanced, to begin to manipulate negative energy to create gateways to the past.…](https://sms4smile.com/quotes/michio-kaku/it-would-take-a-civilization-far-more-advanced-than-ours-unbelievably/) [Michio Kaku](https://sms4smile.com/quotes/author/michio-kaku/) > [“in experimental quantum mechanics we have run right up against what was previously perceived to be a purely philosophical barrier. The experiments are telling…](https://sms4smile.com/quotes/jim-baggott/in-experimental-quantum-mechanics-we-have-run-right-up-against-what/) [Jim Baggott](https://sms4smile.com/quotes/author/jim-baggott/) > [“Listen, O lord of the meeting rivers, things standing shall fall, but the moving ever shall stay.”](https://sms4smile.com/quotes/basava/listen-o-lord-of-the-meeting-rivers-things-standing-shall-fall-but/) [Basava](https://sms4smile.com/quotes/author/basava/) > [A popular feel for scientific endeavors should, if possible, be restored given the needs of the twenty-first century. This does not mean that every…](https://sms4smile.com/quotes/walter-isaacson/a-popular-feel-for-scientific-endeavors-should-if-possible-be/) [Walter Isaacson](https://sms4smile.com/quotes/author/walter-isaacson/) > [Interference between universes at the quantum level means that information transfer takes place between them.](https://sms4smile.com/quotes/james-p-hogan/interference-between-universes-at-the-quantum-level-means-that/) [James P. Hogan](https://sms4smile.com/quotes/author/james-p-hogan/) > [String theory is the most developed theory with the capacity to unite general relativity and quantum mechanics in a consistent manner. I do believe…](https://sms4smile.com/quotes/brian-greene/string-theory-is-the-most-developed-theory-with-the-capacity-to-unite/) [Brian Greene](https://sms4smile.com/quotes/author/brian-greene/) [Browse all 692 Quantum quotes ](https://sms4smile.com/quotes/about/quantum/) ```json { "@context": "https://schema.org", "@graph": [ { "@type": "Quotation", "text": "“Which of the two possibilities corresponds to reality is simply unknown until a definite measurement is made, at which point the quantum state instantaneously changes to reflect the result of that measurement.”", "creator": { "@type": "Person", "name": "Leon M. 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