What is a ‘Cause,’ and Why Does it Happen Before the Effect? Carlo Rovelli
TLDRIn this insightful discussion, Carlo Rovelli, a renowned theoretical physicist, delves into the concept of causation and its relationship with time. He challenges the traditional understanding of cause and effect, suggesting that while fundamental physics laws are time-symmetric and do not distinguish between past and future, our perception of time's arrow and causality arises from thermodynamics and the increase of entropy. Rovelli proposes that causation is a high-level concept used by humans to make sense of an approximate description of the world, where we can act, knowing the past and with an open future. He also touches on the role of memory and agency in forming our understanding of causation. The conversation, moderated by Priya Natarajan, highlights the complex interplay between the objective laws of physics and our subjective experience of time, offering a nuanced perspective on why we perceive causes to precede their effects.
Takeaways
- 🌟 Priya Natarajan, an astrophysicist at Yale, introduces a series on inference, causation, and correlation, emphasizing their importance in various disciplines.
- 🌌 Carlo Rovelli, a theoretical physicist, discusses the concept of causation and its temporal ordering, questioning why causes are perceived to precede their effects.
- 🔍 The series is supported by the John Templeton Foundation and aims for a multidisciplinary exploration, indicating the broad relevance of these topics.
- 🎓 Rovelli's background includes significant contributions to quantum gravity and the philosophy of science, providing a well-rounded perspective for the discussion.
- 📚 His popular science books, such as 'Seven Brief Lessons in Physics' and 'The Order of Time', have been influential, highlighting his ability to communicate complex ideas to a general audience.
- 🤔 Rovelli challenges the traditional views on causation, suggesting that the time orientation of causes and effects may not be as straightforward as commonly believed.
- 🧐 He introduces the idea that both 'primativism' (cause and effect as fundamental) and 'eliminativism' (removing causation from our understanding) are incomplete perspectives.
- 🔄 The physicist argues that while fundamental physics laws are time-reversal invariant, our macroscopic world exhibits time-oriented phenomena due to entropy and thermodynamics.
- ⏳ Rovelli connects the second law of thermodynamics to the existence of traces from the past, which provide a sense of time's arrow and allow for the concept of agency.
- 💭 He also touches on the role of memory and the human experience of time, suggesting that our perception of time is tied to our biological and psychological processes.
- ❓ The talk concludes with an open discussion, inviting questions and further exploration of the intricate relationship between causation, time, and our understanding of the physical world.
Q & A
What is the central theme of Carlo Rovelli's discussion?
-Carlo Rovelli's central theme is the exploration of the concept of causation, its time orientation, and how it is understood and utilized in physics and philosophy. He delves into the nature of inference, the role of causation, and the distinction between correlation and causation.
How does Rovelli propose to reconcile the apparent contradiction between the absence of time-oriented causes in fundamental physics and the ubiquity of causal explanations in science?
-Rovelli suggests that the notion of causation is not fundamental to nature but is a high-level concept that we, as agents, use to interact with the world. He posits that causation arises from the asymmetry of agency and the presence of traces from the past, which are permitted by the second law of thermodynamics.
What is the significance of the second law of thermodynamics in Rovelli's argument?
-The second law of thermodynamics is significant because it allows for the existence of traces from the past and the possibility of agency. It is the source of the macroscopic time-orientation of the world, which in turn influences our understanding and use of causal language.
How does Rovelli address the issue of time in relation to causation?
-Rovelli addresses the issue of time in relation to causation by discussing the difference between the microscopic, time-reversible laws of physics and the macroscopic, time-oriented phenomena we observe. He argues that our perception of time and causation is influenced by our position as macroscopic beings subject to the second law of thermodynamics.
What is the role of agency in Rovelli's explanation of causation?
-Agency, according to Rovelli, is a physical mechanism that allows for the transformation of low entropy into information. It is the capacity of a system to split the future based on the macroscopic past, and it is integral to our understanding of causation as it permits intervention and the creation of information.
How does Rovelli respond to the question about the potential for different observers to make different inferences about the past based on the same traces?
-Rovelli acknowledges that different observers might make different inferences about the past, but he emphasizes that the existence of traces, rooted in the second law of thermodynamics, provides a physical basis for the determination of the past. He suggests that the past is considered fixed because of these traces, which provide a wealth of information about past events.
What is the implication of Rovelli's discussion for the understanding of the nature of time in quantum mechanics?
-Rovelli implies that the understanding of time in quantum mechanics might be more complex than the typical textbook representation suggests. He hints at the possibility that the temporal language used in discussing logical implications is due to the temporal nature of our thinking and memory, rather than an intrinsic temporal aspect of quantum mechanics itself.
How does Rovelli's view on causation relate to the philosophical stance of eliminativism?
-Rovelli argues against eliminativism, which suggests that we should eliminate the concept of causation from our scientific understanding. Instead, he proposes that causation is a useful and ubiquitous concept, even though it is not found in the fundamental laws of physics. It is a high-level description that emerges from our interactions as agents in the world.
What is the role of memory in our understanding of time and causation according to Rovelli?
-Memory plays a crucial role in our understanding of time and causation. Rovelli suggests that because we can remember the past but not the future, this asymmetry in our memory contributes to our perception of time's arrow and our use of causal language to describe and predict phenomena.
How does Rovelli's discussion of causation apply to the field of biology and culture?
-Rovelli posits that biology and culture rely on low-entropy macroscopic variables to function. These variables provide the information that biology and culture use to operate, and their origin can be traced back to past low-entropy states. This suggests that the physical properties of the universe enable the development and existence of complex systems like life and culture.
What is Rovelli's stance on the possibility of different entropy definitions and their role in the past state of the universe?
-Rovelli acknowledges that the definition of entropy is not unique and that it is dependent on the variables we choose to measure. He suggests that it is possible for entropy to have been higher in the past depending on these variables, which is a perspective that aligns with our understanding of the universe's evolution.
Outlines
😀 Introduction to the Series on Inference
Priya Natarajan introduces herself as an astrophysicist at Yale and the director of the interdisciplinary Frankie program. She outlines the aim of a new series on the nature of inference, discussing causation and correlation. The series is supported by the John Templeton Foundation and will involve a multidisciplinary exploration of inference across various fields. The importance of understanding causation in fields like physics is emphasized, as it helps disentangle causation from mere correlation.
🌟 Carlo Rovelli's Introduction and Background
Carlo Rovelli is introduced as a theoretical physicist known for his work on quantum gravity and the foundations of physics. He has held positions in Italy, the United States, France, and Canada, and is currently heading the quantum gravity group at the Center for Theoretical Physics in Marseilles. Rovelli has received numerous awards and has written scholarly books and global bestsellers, including 'Seven Brief Lessons in Physics' and 'The Order of Time.' His expansive mind has led him to explore diverse intellectual traditions, including non-European sources of thinking.
🕰 The Concept of Time and Causation
Rovelli delves into the concept of causation and the time orientation of cause and effect. He argues against the simplistic view that causation is a fundamental aspect of nature, suggesting instead that it is a human construct based on our perception of correlations. He also discusses the role of physics in understanding causation, particularly in the context of thermodynamics and statistical mechanics.
🔄 The Role of Entropy in Causality
Rovelli explains that the past appears fixed due to the presence of traces from past events, which are a result of the second law of thermodynamics. He discusses the concept of agency and how it relates to the idea of intervention in the physical world. Agency, according to Rovelli, is a system that can take a macroscopic past and split it into different microscopic futures, influenced by the second law of thermodynamics.
🤔 The Nature of Inference and Causality
Rovelli explores the nature of inference in general and the temporal language used to describe logical implications. He highlights the role of memory in our understanding of causation and the limitations of induction. He also touches upon the concept of retrocausality and the skepticism of Hume regarding induction, suggesting that while we rely on regularities and induction, we should remain open to the possibility of new understandings.
📚 Conclusion and Future Discussion
The talk concludes with Rovelli emphasizing that causality is not a fundamental aspect of nature but a tool used by humans to interact with the world. He invites further discussion on the topic and thanks the audience for their engagement. An additional discussion with Dr. Eric Winsberg is announced for the following day to delve deeper into the subject.
Mindmap
Keywords
💡Causation
💡Correlation
💡Second Law of Thermodynamics
💡Entropy
💡Agency
💡Intervention
💡Time Orientation
💡Traces
💡Quantum Gravity
💡Philosophy of Science
💡Inference
Highlights
Priya Natarajan introduces a new series of questions on the nature of inference, focusing on causation and correlation, which are crucial for understanding complex phenomena across various disciplines.
The series is supported by the John Templeton Foundation and aims for a multi-disciplinary exploration of inference methods in fields like philosophy, computer science, physics, biology, and organizational behavior.
Carlo Rovelli, a theoretical physicist known for his work on quantum gravity and the foundations of physics, is the inaugural speaker of the series.
Rovelli discusses the time orientation of causation, questioning why causes are perceived to precede their effects and challenging the common understanding of this relationship.
The debate on the nature of time in physics is explored, with Rovelli arguing against the presence of time orientation in fundamental physics laws.
Rovelli suggests that the past appears fixed due to the presence of traces, which are a result of the second law of thermodynamics, leading to an increase in entropy over time.
The future is considered open because the same macro state can evolve into different micro states, which is a concept rooted in the physics of agency.
Causality, according to Rovelli, is not a fundamental aspect of nature but rather a tool used by humans to interact with the world based on our capacity to intervene.
Rovelli proposes that the direction of time is not an inherent feature of nature but emerges from the interplay between the subjective and objective, and the macroscopic and microscopic perspectives.
The role of memory in forming our perception of time is highlighted, with Rovelli noting that we remember the past but not the future, which influences our understanding of cause and effect.
The discussion touches on the concept of agency, where an agent is defined as something that can break past causal links and influence the future, such as a human, a machine, or even a natural event.
Rovelli argues that the low entropy state of the universe in the past may not be a special state of the universe itself but rather a special state with respect to a subsystem.
The idea that our understanding of time and causality is perspectival, dependent on our interaction with and perspective of the universe, is presented.
Rovelli emphasizes the importance of distinguishing between different levels of understanding time, from the psychological to the physical, to avoid confusion and gain clarity.
The potential for different definitions of entropy leading to different interpretations of the past and future of the universe is explored.
The concept of retrocausality in quantum mechanics is discussed, where the notion of cause and effect can be reversed, challenging our usual intuitions about time's arrow.
Rovelli addresses the philosophical skepticism of induction, aligning with Hume's view that we cannot rationally justify predictions about the future based on past observations alone.
Transcripts
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