Zeno's Paradoxes and Mathematics - Ep. 3.3: Why infinitesimals were banished from mathematics

Zeno's Paradoxes and Mathematics - Ep. 3.3: Why infinitesimals were banished from mathematics

Humanities, Social Sciences & Thought Mathematics PBMathematicsPBBPhilosophy of mathematics
🎙 Graham Priest 👥 5K 📅 June 4, 2020 ⏱ 10 min 👁 314 📄 expert opinion 🧭 2026-08-17
Available in: English (current) Français

Keywords

infinitesimalscalculuslimitsZenoRussellmotiondialetheismcontinuityWeierstrassCauchy

Summary

In this lecture, Graham Priest discusses the historical development of calculus and the banishment of infinitesimals in the 19th century. He explains that infinitesimals were dropped not because of inconsistency but due to problems in the theory of continuity. The lecture focuses on how mathematicians like Cauchy and Weierstrass replaced infinitesimals with the concept of limits, which avoids the need for infinitesimals by considering the behavior of functions as intervals approach zero. Priest then connects this to Russell’s account of motion, arguing that motion at an instant is not intrinsic but relational, defined via limits. He addresses potential tensions with determinism, concluding that determinism does not require intrinsic velocity or infinitesimals. The lecture is part of a series on Zeno’s paradoxes and includes a discussion with Emiliano Boccardi.

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Critical Evaluation

Value of the Information & Strength of the Argument

The video provides a clear and insightful explanation of a complex topic in the philosophy of mathematics. Priest’s argumentation is solid, as he distinguishes between the historical reasons for dropping infinitesimals and the philosophical implications. He effectively uses examples to illustrate the concept of limits and how they apply to motion. The discussion with Boccardi adds depth, addressing potential objections and clarifying the relationship between Russell’s view and determinism. The value lies in its accessible yet rigorous treatment of the subject, making it useful for students and enthusiasts of philosophy and mathematics.

Scientific Rigor, Source Quality, Title Accuracy

The lecture is scientifically rigorous, with Priest accurately representing the historical development of calculus and the contributions of Cauchy and Weierstrass. He does not cite specific sources within the video, but the content aligns with established scholarship. The title accurately reflects the content, focusing on the banishment of infinitesimals in the context of Zeno’s paradoxes. The video is part of a larger series, and the description provides links to playlists for further context. No comments were provided for analysis.

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Title / Content Match

The title accurately reflects the content, which focuses on why infinitesimals were banished from mathematics in the context of Zeno's paradoxes.

Quality & Reliability

8/10

The video features Graham Priest, a renowned philosopher and logician, discussing the historical and philosophical aspects of infinitesimals and Zeno's paradoxes. The content is well-structured, accurate in its historical account, and presents a clear philosophical argument. However, it is an opinion/expert lecture rather than a peer-reviewed study, and some claims are simplified for a general audience.

Key Moments

Cited Sources

Concurring Sources

  • Zeno's paradoxes — Provides background on Zeno's paradoxes and their historical context.
  • Infinitesimal — Explains the concept of infinitesimals and their history.

Contribution & Novelties

The video offers a concise and accessible explanation of why infinitesimals were replaced by limits, connecting this historical development to philosophical debates about motion and determinism. It provides a clear account of Russell’s relational view of motion and addresses common misconceptions.

Pour aller plus loin :

  • Zeno’s paradoxes — Overview of Zeno’s paradoxes and their historical impact.
  • Infinitesimal — Detailed article on infinitesimals and their role in mathematics.
  • Non-standard analysis — Modern approach that reintroduces infinitesimals rigorously.
  • Dialetheism — Philosophical position that some contradictions are true, relevant to Priest’s preferred solution.

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Radar Profile

The radar profile shows high scores in quality and reliability, with moderate scores in quantity and technical level. This indicates a well-produced, expert-led lecture that is accessible but not overly technical, making it suitable for a broad audience interested in philosophy and mathematics.

Reliability 8/10