Why subatomic particles aren't fundamental | Sabine Hossenfelder, Hilary Lawson, Tim Maudlin

Episode Overview

• This episode features a panel discussion debating the fundamental nature of reality, specifically centering on the question: "Are particles real?" It explores whether the "building blocks" of the universe are physical entities or merely mathematical tools.
• The conversation moves from a philosophical critique of how humans categorize the world into distinct "things" to a scientific examination of the utility of particle physics versus the actual existence of fundamental matter.
• Listeners interested in the intersection of quantum physics, philosophy of science, and metaphysics will find this relevant as it challenges the standard intuition that the universe is made of discrete, solid objects.

Key Concepts

• The Illusion of "Things": Hilary Lawson argues that dividing the world into distinct objects (particles, tables, people) is a cognitive tool for human survival, not a reflection of reality itself. He suggests that our inability to find an ultimate, indivisible "thing" (splitting the atom, finding quarks within protons) is evidence that the concept of discrete matter is a human projection, potentially masking a more fluid or continuous reality.
• Instrumentalism in Physics: Sabine Hossenfelder adopts an instrumentalist view, positing that mathematics is a tool used to describe the world, not reality itself. From this perspective, "particles" are defined by their mathematical properties (excitations in a field, representations of a group) and their utility in making predictions. whether they are "real" in an ontological sense is considered a philosophical, perhaps unanswerable, question; what matters is whether the model works.
• Quasi-particles and Fundamentalism: The discussion touches on the existence of "quasi-particles"—collective behaviors in materials (like waves) that act like particles. This raises the critical question of whether the "fundamental" particles of the Standard Model (electrons, quarks) might themselves be quasi-particles emerging from a deeper, unknown substrate, suggesting that what we consider fundamental today may just be another layer of emergence.
• Scientific Realism vs. Absolute Proof: Tim Maudlin counters extreme skepticism by distinguishing between absolute proof (impossible in empirical science) and "beyond reasonable doubt." He argues that while we may debate the nature of the fundamental constituents (strings, fields, particles), the evidence from experiments like the double-slit test provides robust grounds to believe in distinct, localizable physical entities, even if our current definitions are imperfect.

Quotes

• At 2:55 - "The division of the world into particulars is not to do with what the world is like, it's to do with how we think. How we think is to divide the world into identities." - This highlights Lawson's anti-realist stance, suggesting that the very concept of a "particle" is a byproduct of human cognition rather than a feature of the universe.
• At 5:13 - "I don't believe that mathematics is real. I think mathematics is a tool that we as physicists use to describe the world." - Hossenfelder explains the instrumentalist approach, separating the mathematical description of a particle (which is precise and useful) from the ontological reality of the particle (which is ambiguous).
• At 8:06 - "Empirical science doesn't run on absolute proof, it's some kind of inference from the evidence we have to what we think of as the most likely or plausible explanation." - Maudlin defends scientific realism, clarifying that the lack of absolute certainty about the nature of matter does not mean we cannot claim knowledge about the physical world based on overwhelming evidence.

Takeaways

• Adopt an instrumentalist mindset when dealing with abstract models; focus on whether a concept (like a particle or a market trend) is useful for prediction and description rather than obsessing over its absolute "reality."
• Challenge the assumption that breaking systems down into smaller parts (reductionism) will always reveal the ultimate truth; consider that the "parts" might be emergent properties of a complex whole, much like quasi-particles.
• Distinguish between "reasonable doubt" and "possible doubt" when evaluating scientific claims; recognize that scientific consensus (like the Earth being round or atoms existing) is based on the convergence of evidence, not mathematical certainty.