253 | David Deutsch on Science, Complexity, and Explanation
Oct 16, 2023
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David Deutsch, a physicist and pioneer in quantum computing, takes us on a mind-bending journey into the complexities of science and philosophy. He discusses his innovative constructor theory and its implications for understanding physics. The conversation dives into the Popper-Miller theorem, exploring the limitations of inductive reasoning. Deutsch also reflects on Hugh Everett's contributions to quantum mechanics and the idea of multiverses. With a focus on explanatory knowledge, he highlights the transformative power of understanding in both science and personal growth.
Knowledge, specifically explanatory knowledge, has the power to transform our understanding of the world and our ability to manipulate it.
Constructor theory provides a new way of understanding physics and other fields, bridging different levels of understanding and offering deeper insight into the fundamental nature of the universe.
Bayesian epistemology, based on assigning probabilities to propositions, is challenged by the Popper-Miller theorem and the importance of obtaining good explanations in assessing knowledge.
Deep dives
The Emergence of Knowledge and Transforming the Universe
The podcast episode explores the idea that the emergence of knowledge has allowed humans to transform the universe. It highlights how knowledge, specifically explanatory knowledge, has the power to change our understanding of the world and our ability to manipulate it. The episode argues that human beings possess both Turing completeness and explanatory universality, which makes us capable of profound transformations. It also touches on the concept of optimistic perspectives and the potential for future breakthroughs, such as artificial general intelligence (AGI).
Constructor Theory and Its Connections
The podcast delves into the concept of constructor theory, which aims to provide a new way of understanding physics and even other fields like biology and chemistry. Constructor theory distinguishes between what can be done and what cannot be done and seeks to uncover the principles governing physical transformations. The theory raises questions about the existence of a universal constructor and the role of knowledge in transformative processes. It suggests that constructor theory has the potential to bridge different levels of understanding and provide a deeper insight into the fundamental nature of the universe.
Bayesian Epistemology and its Criticisms
The podcast explores the topic of Bayesian epistemology and its limitations. It challenges the idea that knowledge is based on assigning probabilities to propositions in a rational mind. The guest argues against Bayesian epistemology, highlighting the Popper-Miller theorem that shows how adjusting credences in accordance with evidence can lead to problematic conclusions. The episode emphasizes the distinction between increasing credence and obtaining good explanations, pointing out that explanations do not necessarily follow the rules of probability theory or logic. Overall, it raises doubts about the validity of Bayesian epistemology as a theory of knowledge.
The Relationship Between Constructor Theory and Epistemology
The podcast draws connections between constructor theory and epistemology, particularly within the context of explanatory universality. It suggests that constructor theory offers a framework for understanding the distinction between what can be done and what cannot be done, which is an essential aspect of knowledge. The episode highlights the affinity between the principles of constructor theory and the philosophical ideas proposed by Karl Popper, such as the importance of ruling out possibilities and maintaining an optimistic perspective. It offers a potential bridge between the fields of physics and philosophy in exploring the nature of knowledge and understanding.
The Paradox of Intransitivity of Support
The podcast episode discusses the paradox of intransitivity of support in reasoning and decision-making. The speaker uses the example of Linda, a woman who may be a banker and a feminist, to illustrate how increasing the probability of one statement does not necessarily increase the probability of its logical consequences. Despite evidence supporting Linda being a banker, it does not automatically support her being a feminist. This inconsistency challenges traditional probabilistic reasoning and highlights the importance of distinguishing between theories and their implications when evaluating evidence.
The Role of Good Explanations
The episode emphasizes the significance of good explanations in scientific inquiry. The speaker argues that good explanations, rather than probabilities, are the key to assessing the viability of theories. They suggest that theories should be evaluated based on explanatory power and the ability to make accurate predictions, rather than adherence to classical decision theory or probability calculus. The speaker also mentions their skepticism about the accuracy and compatibility of quantum theory and general relativity, and their ongoing work on a novel variant of quantum field theory that challenges conventional assumptions.
David Deutsch is one of the most creative scientific thinkers working today, who has as a goal to understand and explain the natural world as best we can. He was a pioneer in quantum computing, and has long been an advocate of the Everett interpretation of quantum theory. He is also the inventor of constructor theory, a new way of conceptualizing physics and science more broadly. But he also has a strong interest in philosophy and epistemology, championing a Popperian explanation-based approach over a rival Bayesian epistemology. We talk about all of these things and more, including his recent work on the Popper-Miller theorem, which specifies limitations on inductive approaches to knowledge and probability.
David Deutsch received his Ph.D. in theoretical physics from the University of Oxford. He is currently a visiting professor in the Department of Atomic and Laser Physics at Oxford. He is a pioneer in quantum computation as well as initiating constructor theory. His books include The Fabric of Reality and The Beginning of Infinity. Among his awards including the Dirac Prize, the Dirac Medal, the Edge of Computation Science Prize, the Isaac Newton Medal, the Breakthrough Physics Prize, and a Royal Society Fellowship.
