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What Is Quantum Mechanics Really Telling Us? | World Science Festival

Does quantum mechanics actually imply that every possible outcome of every decision happens somewhere in an expansive reality? And if so, what does that mean for probability, free will, and our unders

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I really wish that I discovered David Deutsch earlier and I hope that he releases more of his content on YouTube
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This should be a fantastic presentation.
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Awesome.
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I am only 5 minutes and 32 seconds into this and I am totally hooked. Questioning the use of interpretation In physics is expanding my mind.
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@Brian ! This was a great episode. I wonder if David agrees to appear again and discusses more on decision and construction theory. I also wish, the connection with Path Integral Approach with the Everettian picture could be discussed.
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Glad that recent episodes get into the subject immediately without lengthy boring personal introductions
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Thanks sooo much for having Deutsch on, absolute legend
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I love listening to these world science festival discussions. I can grasp some but not all of the discussions.
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Deutsch and Green click well together. Time flies and moves slower in this fun discussion.
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I really appreciate how deeply and sincerely Greene has engaged with the foundations of physics in recent years.
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@snarzetax From YouTube ↗ 21 May 2026 23
Very cool day today! What a talk! Thanks to Dr. Greene and Deutsch!
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Thanks Brian for bringing us another enlightening session. I like David’s line of thinking…

My layman’s view of Quantum, is that just because “anything” CAN happen with probability, doesn’t mean that “everything” IS happening… Reality is one…

You don’t walk out of a casino with an amount of money based on the odds; the winnings are based on what “actually” happened.

Predictions are extremely useful but they are not reality. If we think two things are happening at once, it is most likely that we don’t really understand what is actually going on.

Our brains after all, are finite entities, with finite capabilities, it is quite possible we just don’t get get it and may never get it.

Explaining the future may be “probabilistic” but it is not “reality” just yet. I don’t subscribe to marrying the word “Quantum” with “Reality”

You cannot “measure” the future, you can try to predict it. I don’t know how tall my kid is going to be in 5 years, but I may have a pretty good idea.
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This guy is very bright, and at the same time understandable.
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Fascinating talk. Would've loved if this kept going. Please have him on again
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Great episode, really spoke to me: When I took my undergraduate quantum mechanics course toward my physics B.S. (back in the early 1990s), I was frustrated that the professor did not seem to care about any of these implications or questions. It really turned me off the subject to the point I found private sector invitations and opportunities more interesting and didn't go to graduate school for physics as I'd originally expected. I don't think he ever said, "Shut up and calculate," but that is an absolutely perfect description of the attitude he held and the way he taught the subject. Physics has always been my favorite subject, but the reason is because it is the study of how the universe works (what could be more profound?) and at its best when it cares about the "why" that goes along with it. When you remove those "why" questions, at least for me, it robs the subject of all interest.

By the way, thank you for these discussions that restore the joy in those "why" questions. I used your PBS Elegant Universe video in physics teaching I offered as a optional summer program for interested children many years later. I hope that together we imparted both knowledge and, even more impor
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David Deutsch is one of the greatest minds of our age. More from him please.
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What a privilege to listen to these kinda discussions for free.
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@zbig47 From YouTube ↗ 21 May 2026 79
This was too much fun. Green's precise questions, Deutsch on a serious ride. Beautiful.
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@spgety From YouTube ↗ 21 May 2026 21
I’ve listened to a lot of different people talk on a lot of different subjects here on YouTube. But Brian Green is really a pleasure to listen to and he does such a service to humanity in general by putting this out there.
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@dodgyass11 From YouTube ↗ 21 May 2026 39
Finally these 2 together in superposition ❤