Why Roger Penrose (@Jordan Peterson) is wrong about quantum mechanics
Channel: Edwin Steiner
Date: 2022-05-11

In this video I explain why some statements by Sir Roger Penrose
about the alleged inconsistency and incompleteness of quantum mechanics
are wrong. I discuss crucial points of a consistent understanding
of quantum mechanics, including the notion of the observer,
compatibility of quantum-mechanical predictions, interference
and decoherence, the so-called "measurement problem",
observer dependence, and a view on "reality" that is consistent
with quantum mechanics.

0:00 Introduction
0:25 Sir Roger's claims
0:56 Incomplete vs. inconsistent
1:35 QM does not imply contradictions
2:13 Is QM incomplete?
3:11 True randomness
3:59 Is QM vague about measurements?
4:42 The structure of QM
6:19 The projection postulate
6:56 The quantum state is not an observable
7:56 A pedagogical problem
8:15 The conscious observer
9:10 The Heisenberg cut
10:00 QM does not specify the cut
10:58 A concrete example
11:58 The cut is not physical
12:18 Examples of cuts
13:09 Entanglement and the measurement process
13:43 Observation vs. measurement
14:54 QM describes measurements
15:32 Compatibility of QM descriptions
16:47 Assumed knowledge
18:28 Sketch of compatibility conditions
19:39 Treating macroscopic systems "classically"
20:55 QM vs. classical probability
21:57 Interference and complementarity
22:36 Complementary spin components
23:57 Macroscopic superpositions
27:33 A better question
28:11 Decoherence
30:04 Superpostions concluded
30:35 Decoherence does not determine
31:49 The "measurement problem"
33:29 Observer dependence
34:20 The problem with "objective collapse"
35:04 Observer dependence (cont.)
35:57 QM refutes "realism"
36:35 Reality
36:55 Epilogue
37:40 Outro

My series about quantum mechanics:
Episode 0:   https://youtu.be/aS-o2ysf_O4
Episode 1:   https://youtu.be/85TUPcL7aWQ
Episode 2:   https://youtu.be/7C0ggtMLRFs
Episode 3.1: https://youtu.be/S6Z4FILJVzM

My video "The meaning of PLUS in quantum mechanics":
https://youtu.be/HOjM3t7HGIk

Dr. Peterson's video: https://www.youtube.com/watch?v=TSBOBJsdEuY

Paper by E. Joos & H. D. Zeh about decoherence:
https://doi.org/10.1007/BF01725541
"The emergence of classical properties through interaction with the environment"
Zeitschrift für Physik B Condensed Matter 59, p.223--243 (1985)


My channel: https://www.youtube.com/c/EdwinSteiner
Physics videos playlist: https://www.youtube.com/playlist?list=PLaMCxumvPhAFb6JEmIDQx3w7XaN0p_YJ2

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