Rüdiger Schack: Participatory realism

Rotman Institute of Philosophy
23 Jun 201674:35
EducationalLearning
32 Likes 10 Comments

TLDRThe speaker discusses quantum interpretations, contrasting intrinsic realism with participatory realism, and delves into the nuances of type-1 and type-2 theories. They explore the Copenhagen interpretation and its limitations, introducing 'cubism' as a coherent, agent-centric view of quantum mechanics that treats quantum states as personal judgments rather than objective realities. The talk emphasizes the participatory role of the observer in quantum mechanics and the philosophical implications of viewing quantum states as beliefs rather than knowledge.

Takeaways
  • 📚 The speaker discusses a recent classification of quantum interpretations, distinguishing between 'intrinsic realism' and 'participatory realism', with the latter emphasizing the role of the observer in quantum mechanics.
  • 🌐 The script touches on the complexity of quantum mechanics and the various interpretations that exist, noting that not all fit neatly into the proposed classification but that it is a helpful framework for understanding type-1 and type-2 interpretations.
  • 🔬 The type-1 interpretations, or 'realist interpretations', are characterized by the idea that probabilities are determined by real system properties, often referred to as 'lambda' properties, and are linked to hidden variable theories.
  • 🌌 In contrast, type-2 interpretations, or 'participatory realism', suggest that probabilities are not determined by real properties but are influenced by the observer's knowledge or beliefs, leading to different perspectives like the Copenhagen interpretation and quantum Bayesianism.
  • 🚀 The speaker highlights the importance of the 'no-go theorems' starting with Einstein's 1927 argument, which challenges the idea that quantum mechanics can be in one-to-one correspondence with reality without 'spooky action at a distance'.
  • 📉 The script delves into the implications of the PBR theorem and subsequent works, which explore the tension between realism (lambda) and locality, and how assuming both can lead to contradictions with quantum mechanics.
  • 🌍 The concept of 'locality' is challenged by claims in the media and some philosophers that recent experiments prove non-locality in nature, which contradicts the traditional understanding of locality in physics.
  • 🤔 The speaker introduces the idea of 'Cubism' in quantum mechanics, which views quantum states as states of belief rather than knowledge, and emphasizes the personal experience of the user in the interpretation of quantum mechanics.
  • 🎲 The script explains the role of the Born rule in quantum mechanics, which is seen as an addition to probability theory, providing a way to assign probabilities in situations where ordinary probability theory is silent.
  • 🛰️ The speaker argues against the idea that quantum mechanics provides a complete description of an objective reality, suggesting instead that it offers a tool for agents to navigate and make decisions in an uncertain world.
  • 🧠 The concept of 'participatory realism' is linked to the idea that the physical world may not be as we perceive it through our senses, and that our cognitive systems have evolved to be effective rather than to provide an accurate representation of the world.
Q & A
  • What is the main difference between the two types of quantum interpretations presented in the script?

    -The main difference lies in the bottom part of the classification: intrinsic realism, where probabilities are determined by real system properties, and participatory realism, where probabilities are not determined by real properties but by something else within quantum mechanics.

  • What is the significance of the term 'participatory realism' in the context of quantum mechanics?

    -Participatory realism emphasizes the active role of the observer in quantum mechanics. It was coined by Chris Fuchs and suggests that the outcomes of quantum measurements are influenced by the participation of the observer, rather than being solely determined by the system's properties.

  • How does the script differentiate between type-1 and type-2 interpretations in quantum mechanics?

    -Type-1 interpretations are characterized by the assumption that measurement outcomes are determined by real properties of the system (lambda), whereas type-2 interpretations do not assume real properties and instead consider probabilities as knowledge or belief about the system.

  • What is the Copenhagen interpretation's view on the nature of quantum states and measurements?

    -In the Copenhagen interpretation, quantum states represent knowledge about the system, and measurements are seen as the coupling of a quantum system to a classical system, where the outcome is an irreversible process that results in a definite reading or mark.

  • How does 'cubism' in quantum mechanics differ from the Copenhagen interpretation?

    -Cubism differs by considering quantum states as states of belief and measurements as actions taken by the user to elicit reactions from the world, with the outcomes being experiences induced in the user by the world's reaction.

  • What is the role of the 'Born rule' in the script's discussion of quantum mechanics?

    -The Born rule is central to the script's discussion, as it provides a way to assign probabilities to the outcomes of quantum measurements. It is viewed not as a modification of probability theory but as an addition to it, connecting probabilities for different measurements.

  • What does the script suggest about the relationship between quantum mechanics and the concept of realism?

    -The script suggests that quantum mechanics, particularly through interpretations like cubism, challenges traditional notions of realism by treating quantum states as personal judgments of agents rather than as objective features of the world.

  • How does the script address the concept of locality in quantum mechanics?

    -The script discusses locality in the context of the EPR paradox and Bell's theorem, suggesting that if one assumes locality and real properties (lambda), it contradicts quantum mechanics. The script implies that quantum mechanics may require giving up either locality or the assumption of real properties.

  • What is the philosophical stance of 'Cubism' in the context of the script?

    -Cubism, as discussed in the script, is a philosophical stance that emphasizes the personal and subjective nature of quantum states and probabilities, treating them as beliefs and experiences of the agent rather than objective realities.

  • How does the script relate the concept of 'participatory realism' to the idea of the observer in quantum mechanics?

    -The script relates 'participatory realism' to the idea of the observer by suggesting that the observer is an active participant in the quantum measurement process, with the outcomes being influenced by the observer's actions and beliefs.

  • What is the script's perspective on the applicability and usefulness of quantum mechanics?

    -The script posits that the success of quantum mechanics lies in its utility as a decision-making tool for agents, rather than as a description of an objective reality. It suggests that quantum mechanics is successful because it helps agents navigate and make decisions in the world.

Outlines
00:00
🔍 Introduction to Quantum Interpretations

The speaker introduces a recent classification of quantum interpretations, emphasizing the main differences from previous classifications, particularly focusing on intrinsic realism and participatory realism. The term 'participatory realism' is credited to Chris Fuchs. The speaker discusses the role of probabilities determined by real system properties and distinguishes between type 1 and type 2 interpretations.

05:00
🔍 Type 1 and Type 2 Quantum Interpretations

The speaker explains the distinctions between type 1 and type 2 interpretations, highlighting the role of lambda in determining probabilities. They discuss how recent no-go theorems, starting from Einstein's ideas in 1927, have influenced these interpretations. The talk also touches on the PBR theorem and its implications for quantum mechanics, emphasizing the tension between lambda, locality, and the nature of quantum mechanics.

10:02
🔍 Copenhagen Interpretation vs. Cubism

The speaker contrasts the Copenhagen interpretation with Cubism, focusing on the role of measurement and the state change upon measurement. Cubism is presented as an approach where quantum states are seen as states of belief, and measurement outcomes are personal to the user. This approach is described as taking the idea of observer participation further than typical Copenhagen interpretations.

15:03
🔍 Wigner's Friend and Participatory Realism

The speaker discusses the Wigner's Friend paradox and its implications for quantum interpretations. They explain how Cubism resolves this paradox by making measurement outcomes personal to the observer, avoiding the paradox altogether. The speaker also touches on the problematic terminology of 'observer' and 'participatory realism,' arguing for more active terms like 'agent' or 'user.'

20:04
🔍 Personal Probabilities and Decision Theory

The speaker delves into the concept of personal probabilities within Cubism, grounded in decision theory. They explain how probabilities are personal judgments of the agent and how the Born rule connects these probabilities. The discussion includes a brief history of the development of personal probability theory and its application to quantum mechanics.

25:08
🔍 Normative vs. Descriptive Theories

The speaker distinguishes between normative and descriptive theories, emphasizing that the Born rule in Cubism is a normative rule. This section explains how personal probabilities and the Born rule provide a coherent framework for understanding quantum mechanics without assuming an objective reality. The speaker also discusses the role of empirical data in shaping these beliefs.

30:08
🔍 Implications for Quantum Mechanics

The speaker addresses potential misconceptions about Cubism, emphasizing that it is not solipsism. They explain that Cubism treats experiences and agency as fundamental, which changes how we understand interactions and measurements in quantum mechanics. The discussion also touches on the evolutionary perspective on perception and its alignment with Cubist ideas.

35:09
🔍 The Role of Experience in Cubism

The speaker elaborates on the fundamental role of experience in Cubism, arguing that experience is more central than objective entities like atoms or wavefunctions. This section discusses how agency and personal judgments shape our understanding of quantum mechanics and the world. The speaker also highlights the practical success of Cubism as a decision tool.

40:12
🔍 Autonomy and the Nature of Reality

The speaker discusses the concept of autonomy in Cubism, contrasting it with the idea of irreducible randomness. They explain how Cubism views the world as malleable and shaped by the actions of agents, which impacts future experiences and expectations. The section concludes with reflections on the consistency and completeness of type 2 interpretations like Cubism.

45:15
🔍 Realism and Instrumentalism in Cubism

The speaker explores the philosophical implications of Cubism, suggesting that it offers a form of realism or instrumentalism that emphasizes the importance of experience and agency. They argue that Cubism provides a coherent and consistent framework for understanding quantum mechanics without relying on objective reality. The discussion includes reflections on the practical and theoretical success of Cubism.

50:18
🔍 Quantum Mechanics as a Decision Tool

The speaker responds to questions about the scope and application of quantum mechanics within Cubism. They emphasize that quantum mechanics is a tool for predicting outcomes and making decisions, not necessarily a map of an objective reality. The speaker discusses the practical implications of this perspective for fields like nuclear waste management and other long-term predictions.

55:19
🔍 The Philosophical Foundation of Cubism

The speaker elaborates on the philosophical foundations of Cubism, stressing the importance of starting from experience and agency rather than objective entities. They argue that this approach avoids many of the interpretational problems of traditional quantum mechanics and offers a more coherent and practical framework for understanding the world.

01:24
🔍 Realism, Solipsism, and Quantum Interpretations

The speaker addresses concerns about solipsism and realism in Cubism, explaining that Cubism avoids these issues by focusing on personal experiences and agency. They discuss how Cubism provides a consistent framework for interpreting quantum mechanics and making predictions, without assuming a fully objective reality.

06:25
🔍 Type 2 Interpretations and Practical Applications

The speaker concludes by summarizing the key differences between type 1 and type 2 interpretations of quantum mechanics, emphasizing the practical success of Cubism. They argue that Cubism offers a robust and consistent framework for understanding quantum mechanics, grounded in personal probabilities and decision theory, rather than objective reality.

11:49
🔍 Final Reflections on Cubism

The speaker wraps up the discussion by reflecting on the broader implications of Cubism for science and philosophy. They emphasize the practical success of Cubism as a decision tool and its consistency with empirical data. The final remarks highlight the importance of agency and experience in shaping our understanding of quantum mechanics and the world.

Mindmap
Keywords
💡Quantum Interpretations
Quantum interpretations refer to various philosophical and scientific perspectives on the meaning and implications of quantum mechanics. In the video, the speaker discusses a recent classification of these interpretations, highlighting the differences between intrinsic realism and participatory realism, which are central to understanding the philosophical stance one might take on quantum phenomena.
💡Intrinsic Realism
Intrinsic realism is a concept within quantum mechanics where probabilities are determined by real system properties, often referred to as lambda. The speaker mentions this as one of the main categories in the classification of quantum interpretations, suggesting a belief in the existence of properties independent of observation or measurement.
💡Participatory Realism
Participatory realism, a term credited to Chris Fuchs, is the idea that the observer plays an active role in bringing about the reality of quantum systems. The speaker discusses this as a key distinction in the classification, where probabilities are not determined by pre-existing real properties but are influenced by the participant's interaction with the system.
💡Quantum Mechanics
Quantum mechanics is the branch of physics that deals with the behavior of particles at the quantum level. The video revolves around different interpretations of quantum mechanics, reflecting on how they shape our understanding of reality, measurement, and the role of the observer in quantum events.
💡Measurement Problem
The measurement problem in quantum mechanics addresses the question of why the wave function collapses to a definite state upon measurement. The script discusses how different interpretations, such as the Copenhagen and Cubitt's interpretations, offer different explanations for this phenomenon.
💡Copenhagen Interpretation
The Copenhagen interpretation is a traditional view in quantum mechanics where the act of measurement causes a quantum system to assume a definite state. The speaker contrasts this with other interpretations like Cubism, emphasizing the role of the observer and the nature of measurement outcomes.
💡Cubism
Cubism, in the context of quantum mechanics, refers to an interpretation that emphasizes the role of the observer in shaping the reality of quantum systems. The speaker discusses how in Cubism, quantum states are considered states of belief, and measurements are personal experiences rather than objective events.
💡Born Rule
The Born Rule is a principle in quantum mechanics that provides the statistical interpretation of the wave function, relating the square of the wave function's amplitude to the probability of finding a particle in a particular state. The speaker describes the Born Rule as an addition to probability theory, assigning probabilities based on personal judgments rather than objective properties.
💡Locality
Locality is the principle that physical processes occurring at one location do not affect those at another location instantaneously. The script touches on the concept of locality in the context of debates about non-locality in quantum mechanics and its implications for interpretations like the Copenhagen and Cubism.
💡Non-locality
Non-locality is the idea that quantum entities can be instantaneously correlated regardless of the distance separating them, challenging the principle of locality. The speaker discusses how experiments and philosophical interpretations have questioned the traditional understanding of locality in light of quantum phenomena.
💡Bayesian Probability
Bayesian probability is a type of probability theory that incorporates an individual's degrees of belief. The speaker mentions Bayesian probability in the context of Cubism, where quantum states are seen as personal judgments or beliefs about future experiences, rather than objective realities.
💡Observer-Participant
Observer-Participant is a concept that emphasizes the active role of the observer in the measurement process, influencing the outcome of quantum events. The speaker discusses this concept in relation to participatory realism and Cubism, highlighting the participatory role of the user in quantum mechanics.
Highlights

Introduction of a recent classification of quantum interpretations on the archive, suggesting a further development from the initial classification.

Discussion on the main difference in the classification scheme, focusing on 'intrinsic realism' and 'participatory realism'.

Clarification that the term 'participatory realism' was coined by Chris Fuchs and suggested for the classification.

Explanation of how probabilities in quantum mechanics are determined by real system properties or not, distinguishing between types of interpretations.

Introduction of Type-1 and Type-2 interpretations, with Type-1 involving real properties and Type-2 lacking 'lambda' properties.

Delineation between 'epistemic theories' and 'doxastic theories' within Type-2 interpretations, relating to knowledge and belief respectively.

Background on Type-1 interpretations, particularly intrinsic realism, and its connection to hidden variable theories.

Discussion on the impact of no-go theorems, starting with Einstein's 1927 argument against 'spooky action at a distance'.

Mention of the PBR theorem and subsequent work, showing tension between assuming real properties and quantum mechanics.

Critique of the popular claim that recent experiments prove non-locality in nature, challenging the principle of locality.

Differentiation between Type-1 and Type-2 theories regarding the role of real properties and locality in determining probabilities.

Exploration of Type-2 interpretations, suggesting they do not assume real properties and remain coherent and meaningful.

Comparison between the Copenhagen interpretation and cubism, emphasizing the user's role in quantum mechanics.

Discussion on the role of the user in cubism, where measurements are personal and tied to the user's experiences.

Critique of the Copenhagen interpretation's objectivity in measurements versus cubism's subjectivity.

Explanation of participatory realism in cubism, where the observer is an active participant in the measurement process.

Differentiation between 'epistemic' and 'doxastic' participatory realism, focusing on knowledge versus belief.

Introduction of personal probability theory and its normative character, as opposed to descriptive theories.

Discussion on the Born rule in cubism, viewed as an addition to probability theory rather than a modification.

Reflection on the implications of viewing quantum states as personal judgments, embracing the subjectivity of probabilities.

Critique of the idea that quantum mechanics provides a description of an objective reality, suggesting it is a tool for decision-making.

Conclusion that cubism is a minimalist interpretation that does not claim to provide a complete picture of the world but offers a coherent tool for survival.

Transcripts
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