StarTalk Radio – The Limits of Knowing with Elise Crull

Host: Neil deGrasse Tyson
Guest: Dr. Elise Crull, Associate Professor of Philosophy, CUNY
Co-host: Chuck Nice
Date: November 4, 2025

Episode Overview

In this episode, Neil deGrasse Tyson and Chuck Nice welcome Dr. Elise Crull back to StarTalk Radio to explore the historic and ongoing relationship between philosophy and physics. The conversation traces how these disciplines have both intertwined and drifted apart, focusing on questions about objectivity, foundational concepts in science, and the particularly thorny issues emerging from quantum mechanics. With humor and depth, this episode sheds light on how we know what we know, the limits of scientific knowledge, and why philosophy still matters to cutting-edge physics today.

Key Discussion Points & Insights

1. What Is Philosophy Today?

[05:17]

• Dr. Crull describes philosophy as "asking similar questions in always new contexts—scientific, cultural, political—which makes every effort distinct," referencing Bas van Fraassen’s definition.
• Neil reflects on how science and philosophy began as a singular pursuit before professional boundaries emerged.
• Quote:

  "Every time you ask it, you're in a new context, new scientific context, new cultural context, new political context, and you're a different person asking it." — Elise Crull [05:59]

2. The Shared Evolution of Physics and Philosophy

[07:38] - [15:18]

• The conversation traces the intellectual lineage: Descartes → Newton → Leibniz, highlighting how historical science texts like Newton’s Principia began as works of “natural philosophy.”
• Dr. Crull spotlights Émilie du Châtelet—a pioneering woman physicist/philosopher often overshadowed by her male contemporaries—for her foundational work and her translation/commentary on Newton.
• The need for foundational “rules” (axioms) is fundamental both to philosophy and science.
• Quote:

  “You gotta bite the bullet somewhere. And what follows derives within those constraints.” — Elise Crull [14:10]

3. Specialization, Fragmentation, and the Wall Between Disciplines

[20:22]

• Dr. Crull and Neil note the increasing specialization of science post-Industrial Revolution, which eroded cross-disciplinary dialogue.
• In the late 19th and 20th centuries, especially after WWII and the Manhattan Project, physics became pragmatic and “bordered,” with a “shut up and calculate” mentality prevailing.
• Historical examples (James Conant’s Harvard program) show attempts to keep philosophy linked to physics.
• Quote:

  “It becomes, in the US, very pragmatic… shut up and calculate mentality. That really dominates through the Cold War era.” — Elise Crull [23:34]

4. The Role of Philosophy in Scientific Progress

[24:12] - [27:30]

• Neil presses: is this professional wall detrimental? Dr. Crull insists impermeable boundaries harm any field, not just science.
• The utility of philosophical reflection: major paradigm shifts (e.g., Einstein’s special relativity) demanded reevaluation of basic concepts like “simultaneity.”
• Philosophy helps scientists challenge unexamined assumptions.
• Quote:

  “Are we really understanding this concept the way we should be?... We’re getting into regimes in physics where we’re beyond what is empirically testable… What then do you use?” — Elise Crull [28:09]

5. Objectivity, Measurement, and Quantum Weirdness

[34:01]

• Objectivity—once considered an untouchable hallmark of science—faces new challenges in quantum mechanics, where observer and apparatus can’t be wholly separated from the system.
• The idea of “decoherence” (how quantum systems appear classical at larger scales) and entanglement/nonlocality are unpacked.
• Neil asks: can quantum physics ever be as intuitive as classical physics?
• Quote:

  “When systems interact, something weirdly different happens… You can no longer talk about the physics of one without considering the other.” — Elise Crull [38:02]

• Memorable Analogy:

  “If you want to study a bird, you can watch it fly… but you also need to dissect it... but then it’s not the bird you were studying.” — Elise Crull [35:07]

6. Quantum Entanglement & Nonlocality

[45:15] - [49:52]

• Dr. Crull recounts how even Nobel Prize-winning physicists disagree on what “nonlocality” actually means.
• Nonlocality: entangled particles are not just correlated but linked in ways that defy explanation by classical signal exchange—even after interaction ceases.
• They reject the “wormhole” as an easy explanation, noting entanglement is too ubiquitous and flexible for that.
• Quote:

  “Entanglement understood as nonseparability… is the thing that causes departure between classical theories and quantum theories.” — Elise Crull [38:02]

7. Can Philosophy Still Contribute Directly to Physics?

[58:25] - [63:08]

• Neil poses his skepticism: can modern philosophy contribute materially to physical science as it did in the past?
• Dr. Crull counters that the boundary between philosophical and scientific reasoning is blurry, and that today’s best philosophers of science are scientifically literate and intertwined with the work of practicing scientists.
• Chuck Nice highlights that these boundaries themselves may be the problem.
• Quote:

  “There’s just different ways of viewing the world… when we have conversations, it’s interesting, and we learn things. It is a dialectic.” — Elise Crull [62:15]

8. What’s the Future? Is Quantum Physics Ever “Intuitive”?

[51:43] - [55:51]

• Dr. Crull contends that quantum mechanics will likely never be as intuitive as classical physics because our brains evolved in a classical world.
• Philosophy’s function is to help unmoor scientists from ingrained assumptions.
• Younger scientists show more interest in philosophical context, meaning more cross-dialogue may be coming.
• Quote:

  “Knowing quantum theory is evolutionarily maladaptive… nerds like myself doing problem sets, and here comes the saber-toothed tiger…” — Elise Crull [53:17]
  “There’s a way that quantum is never gonna be intuitive to us the way it is. But that’s why engaging with these philosophical questions [matters].” — Elise Crull [54:09]

Notable Quotes & Memorable Moments

• On change and humility:

  “People who think hard are the ones who change their minds the most, because I think there's a bit of humility there.” — Elise Crull [06:27]

• On specialization:

  “Liberal arts training is being kicked like a poor little puppy.” — Elise Crull [22:10]

• On the ambitions of science:

  "There's no reason why nature should give a damn about our aesthetics." — Neil deGrasse Tyson [26:00]

• Einstein to Schrödinger (letter):

  “Physics is a kind of metaphysics… we do not know what reality is. We know it only through our physical description. They are wedded together.” — Albert Einstein (read by Elise Crull) [65:17]

• On collaboration:

  “Let's all—who cares where it comes from? All hands on deck.” — Chuck Nice [50:10]

• On ossification:

  “It’s like…an ossification that happens because of the practice itself, and then…philosophy comes in to help change the thinking altogether.” — Chuck Nice [55:12]

Significant Segments & Timestamps

• [05:17] – What is philosophy? (Bas van Fraassen’s definition; philosophy evolves contextually)
• [07:38] – How physics grew out of philosophy; Descartes, Newton, Leibniz, and women in early philosophy
• [22:10] – How specialization and university structures discourage broad, interdisciplinary thinking
• [24:12] – The “wall” between modern physics and philosophy; when and why it formed
• [28:09] – The importance of philosophical challenges to scientific concepts; Einstein as a philosopher-physicist
• [34:01] – How objectivity is challenged by quantum mechanics; measurement and the observer effect
• [38:02] – Entanglement and nonlocality; why quantum is so weird
• [45:15] – Modern debate about the meaning of nonlocality, even amongst Nobel laureates; experiments and implications
• [51:43] – Can quantum physics ever be made intuitive? Why our minds resist it
• [58:25] – The ongoing value (and limitations) of philosophy for scientific progress
• [65:17] – Einstein’s letter: “Physics is a kind of metaphysics...”

Tone & Style

The episode blends deep, academic discussion with StarTalk’s signature wit and accessibility. Neil’s curiosity and skepticism blend with Chuck’s comic relief, while Dr. Crull’s expertise keeps the discussion grounded in real history and the lived experience of scientific inquiry. The tone is conversational, lively, and studded with candid admissions about the frustrations and exhilarations of pushing at the limits of human knowledge.

Summary Takeaway

This episode makes a compelling case that philosophy and physics, though distinct in modern academia, are far richer when brought into conversation. Science is always embedded in philosophical assumptions—about truth, objectivity, and what counts as explanation. As quantum physics continues to challenge our intuitions and technical boundaries, philosophical thinking and cross-disciplinary dialogue will only become more vital. As Elise Crull demonstrates, asking “why” is never out of date, and the “limits of knowing” are exactly where the most exciting discoveries—and debates—are happening.