Ep 202: David Deutsch’s ”The Fabric of Reality” Chapter 10 ”The Nature of Mathematics” Part 3

Sam Kuypers is a theoretical physicist who specialises in the physics of time. If you have the time, Sam can take up as much of it as you like telling you about how our ideas of time have changed…over time. As Sam will reveals: times, they are not a-changing. But there is change! Newtonian physics has a notion of time (or at least Newton himself did), Relativity as discovered by Einstein in the early 1900s radically transformed our notion of what time is and now, in the 21st Century, Sam Kuypers and others are beginning to develop a quantum theory of time. And this is why Sam joins me for this episode as we unpack time as a quantum concept: the very topic of Chapter 11 of “The Fabric of Reality” and go deep on Sam’s more recent contributions to our understanding of the reality of time. Appropriately, time stamps are below.   You may have to take your time with some of this.     00:00 - Introduction to this episode 05:04 - Introduction to Sam Kuypers 06:30 - The day-to-day of a theoretical physicist 10:30 - What led Sam to Oxford University 12:10 - What was Sam’s doctoral thesis about? 15:20 - The importance of Everett 16:30 - “Classical” Time and “universal time”. 27:00 - Julian Barbour and time as a series of instants 30:35 - Spacetime and the timeless view of physical reality. 33:35 - The clash of General Relativity and Quantum Theory I 37:20 - The clash of General Relativity and Quantum Theory II 40:40 - c-numbers and q-numbers 42:30 - The significance of (non) commutability (i.e the Heisenberg Uncertainty Principle). 46:05 - The Page-Wooters Construction (Quantum Time I). 53:15 - Can there be change if nothing is ever changing? (Quantum Time II) 55:31 - The Heisenberg vs Schrödinger “Pictures” of Quantum Theory. 57:35 - What is “locality” in physics? 58:40 - Entanglement and: "Does Quantum Theory allows for faster than light communication?”  1:00:48 - Unitary Quantum Theory (vs: Everettian Quantum Theory) 1:05:33 - Philosophical Realism, Physics 1:06:40 - Does Time Exist? 1:07:58 - Is Time Travel Possible? 1:11:30 - How did Sam find his way into physics? 1:14:30 - The Dutch Enlightenment vs The British Enlightenment 1:20:50 - The Netherlands, international trade, tolerance and specialisation 1:23:08 - The Invention of Free Trade and misconceptions with long lifetimes. 1:16:30 - The peculiar rivalry between European Allies 1:28:40 - Prosperity and Pessimism: Are both on the ascendency? 1:32:19: Why are people special? 1:37:14: Liberalism, Authoritarianism and Climate Change 1:40:25: Science, Morality and (eg: Dutch) Innovation 1:43:30 - Concluding Remarks         

Part 2: Time is in the instant. The instant is not in time. More on the quantum theory of time and how the "spacetime" view of time, and the flow of time are false. How time relates to the "block universe" model and how the multiverse fixes the paradoxes at the heart of our common sense (and classical physics) ideas about time - more readings from "The Fabric of Reality" chapter 11 and in addition: A couple of acrostics about David Deutsch in terms of "Popper". David's changing view of free will. Readings on "free will" from "A Science of Can and Can't" by Chiara Marletto. A summary of a paper by Marletto and Vedral on the "Page and Wooters" construction. Brief remarks on Marietto's "Constructor Theory of Thermodynamics" Kuyper's thesis "Developments in Unitary Quantum Theory" The paradoxes involved in trying to picture time using diagrams. Machian Dynamics (Ernst Mach's idea about absolute space and time being false and instead how the universe has dynamics of its own). The Schrödinger vs Heisenberg Pictures The Kuypers and Deutsch paper on "Everettian Relative States in the Heisenberg picture" "And other topics" as Sam Harris says. Reference: Mentions of Sam Kuypers paper on "q number time" throughout: https://royalsocietypublishing.org/doi/full/10.1098/rspa.2021.0970

This is really "episode 0" but not quite because we do indeed get to some readings and unpackings of the chapter. But in the overall scheme, that forms a minor part of a longer introduction to the "common sense" understanding of time and then to some relativity (of simultaneity) and reflections on the work of other physicists and popularisers.   Note clips from "The Lord of the Rings" and "Spaceballs" movies are owned by their respective copyright holders.

Some more long introductory remarks and commentary throughout readings of the closing pages of the chapter culminating in the explanation of the "punchline" conclusion of the chapter which is: "Necessary truth is the subject matter of mathematics. It is not the reward we get for doing mathematics". This is a good exploration of fallibility, the relationship of physics to mathematics and how science is, in a sense, logically prior to mathematics (and logic for that matter!)...all because proof is a physical process.

The nature of proof and mathematics as a creative enterprise. Not all that is true can be proved as such, the high hopes of David Hilbert for placing the entirety of mathematics on a "firm foundation", the mathematical world-shattering results of Kurt Gödel which frustrated that project, a history of proof and finally Roger Penrose and whether human brains are computers in the Turing sense. And some very long remarks by me, especially in the introduction. Become a subscriber at https://patreon.com/tokcast?utm_medium=unknown&utm_source=join_link&utm_campaign=creatorshare_creator&utm_content=copyLink

Drawing on Chapter 15 "The Evolution of Culture" from "The Beginning of Infinity" by David Deutsch and then applying it to some special cases. Come and chat to me about this or anything else at https://www.getairchat.com/brett Timestamps: 00:00 Speech, Trade and Democracy 02:39 Is Democracy under attack? 07:05 Free Speech as Error Identification 09:14 Limits on Free Speech? 13:02 Case Study 1: North Korea 14:18 Case Study 2: Afghanistan and Iraq 17:30 Case Study 3: South Korea 19:43 Case Study 4: China 24:43 The Evolution of Culture by David Deutsch 1 29:43 Protecting liberty in Western Nations 30:30 Bringing Liberty to nations without it. 32:25 Case Study 5: Japan 35:01 Immigration: Why worry? 35:58 The Evolution of Culture by David Deutsch 2 39:01 Preserve the means of error correction at all costs Support me at www.bretthall.org

00:00 Introduction 08:03 Interview Begins 09:42 How Chiara found herself at the foundations of physics 15:30 How Chiara found Everett 19:13 No Special Physics is required for Observers 21:02 What is a counterfactual? How is it linked to a constructor? 29:05 What is (classical) information? How is it different to quantum information? 32:30 Quantum Information is more constrained. This makes it more powerful. 34:08 Is the universe made of information? 38:04 The Simulation Hypothesis 40:33 The second law of thermodynamics 53:16 The AI Apocalypse? 58:02 How do we help a human become passionate about knowledge? 59:39 The Fine Tuning Problem 01:07:48 The Constructor Theoretic Notion of Knowledge 01:10:52 Constructor Theoretic Knowledge as a window on the origins of life. 01:12:16 The links between physics, epistemology and biology 01:14:15 Experimentally testing the quantum nature of gravity 01:26:05 Where to find out more   Support me by following the links at www.bretthall.org

The certainty of mathematics and its place in the supposed hierarchy of subjects (assumed to be above science which is itself above philosophy in turn). Some more remarks on Bayesianism and somehow ghosts and alien life.

Everything and more one might ever want to know about the topic...that other epistemology people often talk about. The central project is to distinguish between 4 "species" of what is often called "Bayesianism"  1. Bayes' Theorem. 2. Bayesian Statistics. 3. Bayesian Reasoning 4. Bayesian Epistemology.    Actual timestampes and chapters are:   00:00 - Introduction to this podcast 02:55 Epistemology  11:30 Substrate Independence 12:30 Inexplicit Knowledge/Knowledge without a knower 21:30 Explanatory Universality and Supernaturalism 24:30 When we lack good explanations 29:00 Rational Decision Theory  33:39: Bayes’ Theorem 41:40 Bayesian Statistics 1:07:50 Bayesian Reasoning 1:16:00 Bayesian “Epistemology” 1:20:13: Quick Recap 1:20:49 A question from Stephen Mix 1:21:50 “Confidence” in epistemology 1:26:13 Measurement and Uncertainty 1:31:50 Confidence and experimental replication   Join the conversation https://getairchat.com/s/p3ql7kNB

This episode is an introduction to the chapter. Although there are some readings, they are limited and I provide context by diving deep into David's more recent work on all this. Specifically we go through the connection of Chapter 10 here (published in 1997) and Chapter 5 "The Reality of Abstractions" from "The Beginning of Infinity" (published in 2011) and then also in light of David's recent speech given at his Dirac Medal award ceremony (published in 2017) - here is the timestamped link to that https://www.youtube.com/live/J7HeDX_7... and the text of that speech is online here: https://www.daviddeutsch.org.uk/wp-co... None of that is essential reading (or listening) for this episode - but it can help. As always - buy "The Fabric of Reality" and read along as I never read the entire chapter - just excerpts!