Philosophy of Physics Meets Quantum Engineering with Elise Crull

Philosophy of Physics Meets Quantum Engineering with Elise Crull

Why This Episode Matters

Elise Crull is Associate Professor of Philosophy at CCNY and the CUNY Graduate Center, co-author with Guido Bacciagaluppi of The Einstein Paradox (Cambridge, 2024), and was named a Fellow of the American Physical Society in 2025 for her archival work recovering voices like Grete Hermann from the foundations of quantum mechanics. She was also one of the speakers on Helgoland in June 2025 for the centenary of quantum mechanics — opening, as Sebastian notes, by thanking the organizers for the courage to invite a philosopher.

This conversation matters because the truce between physicists and philosophers of physics is over. Quantum computing has turned interpretive questions — what counts as entanglement, what decoherence really is, whether causal order can be put in superposition — into engineering questions with budget consequences. If you build, fund, or write about quantum hardware, this episode will sharpen how you hear the words being used around you.

Sponsor

This episode is brought to you by Outshift, Cisco's incubation engine. The need for computational power is rapidly increasing in every sector. From drug discovery to material innovation to complex financial modeling, classical systems are reaching their absolute limits. It’s time for a paradigm shift. The answer is a scalable quantum network, built on open standards and vendor-agnostic architecture. By uniting distributed quantum devices, you unlock limitless computational power. Learn more about the Cisco Universal Quantum Switch at Outshift.com.

Go deeper with the blog post.

What We Get Into

• Why "decoherence" and "noise" are not interchangeable, and why error correction strategy depends on telling them apart
• The six-plus working definitions of entanglement currently circulating in physics — and why "classical entanglement" makes a philosopher's eye twitch
• What Einstein actually objected to in EPR (hint: it wasn't really determinism), drawn from Schrödinger's "Einstein-Paradoxon" correspondence folder
• Indefinite causal ordering: whether the experimental speedups reflect genuinely acausal physics or our stubbornly classical definitions of "cause" and "signal"
• How monogamy of entanglement is only monogamous with respect to a single degree of freedom — and why that nuance is already being exploited in entanglement harvesting
• Why "it's just a tool" is the most insidious thing an engineer can say about quantum or AI technology
• How the standard heroic-origin story of quantum mechanics structurally erased experimentalists — many of them women like Hertha Sponer — and what that pattern predicts about quantum computing's own emerging origin story
• What Grete Hermann did to von Neumann's impossibility proof forty years before anyone listened
• Why Crull thinks the next physical theory, whatever succeeds quantum field theory, is likely to be stranger, not tamer

Resources & Links

Guest Links

• Elise Crull — CCNY Faculty Profile — Her institutional home, with current research interests and talks.
• Elise Crull — CUNY Graduate Center Profile — Full publications list including forthcoming work.
• Elise Crull — Academia.edu — Preprint archive, including her 2024 Leggett–Garg/Feyerabend paper and earlier decoherence work.

Books & Papers

• The Einstein Paradox (Bacciagaluppi & Crull, Cambridge UP, 2024) — The archival reconstruction of the debate EPR unleashed; the centerpiece of the conversation.
• Ryckman's BJPS review of The Einstein Paradox (2025) — A scholarly assessment of what the book changes about how we read 1935.
• "Realism with Quantum Faces: The Leggett–Garg Inequalities as a Case Study for Feyerabend's Views" (Crull, 2024) — Her most recent standalone article on macroscopic realism.
• "Physics Scratches a Philosopher's Itch" — APS Physics (2022) — A feature on her work on indefinite causal ordering and causation.

Helgoland & History

• Physics World: Helgoland 2025 — the Inside Story — Post-event report on the centenary where Sebastian and Elise first met.
• AIP: "What Happened on Helgoland" — Historiographical pushback on the Heisenberg origin myth.
• AIP: Crull on Hertha Sponer and the path to wave/particle duality (2026) — Her most recent piece on how standard histories minimize experimentalists.

For General Audiences

• StarTalk: "The Philosophy of Physics with Elise Crull" (June 2025) — Crull with Neil deGrasse Tyson, kicking off the Einstein Paradox promotion cycle.
• StarTalk: "How Quantum Physics Complicates Objective Truth" (April 2026) — A complementary, more recent treatment of the same themes.

Key Quotes & Insights

• On what philosophy is for: "Every aspect of science we do requires interpretation, because the world isn't just out there. We make choices about how to encounter it."
• On decoherence vs. noise: Crull notes the question physicists at Duke recently raised with her — how do you tell the difference between decoherence and noise? — and stresses that one is something you shield against, the other is something else entirely. Error correction strategy depends on the distinction.
• On what really bothered Einstein: Despite the popular story, "He wasn't as concerned about determinism as you would think." What Einstein wanted was a theory whose mathematics had a one-to-one mapping to individual systems with their own states — and entanglement broke that.
• On indefinite causal order: Experimentalists often equate causation with signaling constraints, but "those are very different things." The superposition-of-causal-orders results may reveal less about causation than about the fact that temporal ordering itself remains defined in irreducibly classical ways.