Things Which Will Never Exist

Things Which Will Never Exist

by Isaac Arthur

Formal & Physical Sciences Astronomy & Cosmology PGAstronomy, space and timePGKCosmology and the universe
🎙 Isaac Arthur 👥 1.2M 📅 August 22, 2019 ⏱ 29 min 👁 613K 📄 science communication 🧭 2026-08-26
Available in: English (current) Français

Keywords

impossiblephysicsPlanck lengthHubble volumeimmortality

Summary

In this 200th episode of Science & Futurism with Isaac Arthur, the host explores the concept of things that may never exist, even in the far future. He begins by contrasting scientific futurism with science fiction, highlighting that while some sci-fi staples like gravity manipulation might be possible, faster-than-light travel and communication are likely impossible due to causality constraints. He then discusses the limits of observation, explaining why we can never see an atom with light and how the Planck length represents a fundamental minimum scale. The episode also covers the impossibility of an accurate map of the entire universe, as regions beyond the Hubble volume are forever unreachable. Isaac Arthur argues that true immortality is unattainable, as infinite time and finite probability lead to eventual death, and even digital backups face entropy. He also debunks the Library of Babel as physically impossible due to the sheer number of combinations. The discussion extends to the improbability of compatible alien biology and interspecies romance, as well as the impracticality of teleportation and perpetual motion machines. Finally, he touches on the impossibility of resurrecting the dead from decayed remains, though he notes that a copy might be made from a snapshot of the past. The episode concludes with a reflection on the show’s journey and a thank you to the audience.

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Critical Evaluation

Value of the Information & Strength of the Argument

The video provides substantial value by systematically addressing a wide range of proposed impossibilities, grounding each in scientific principles. The argumentation is solid, using logical reasoning and established physics to explain why certain things are impossible or highly impractical. For instance, the explanation of FTL travel’s conflict with causality is clear and compelling. The host also effectively distinguishes between mathematical possibilities and physical realities, as seen in the discussion of negative dollars or the Library of Babel. The arguments are well-structured, building from fundamental physics to more speculative but logically constrained ideas, and the host acknowledges uncertainty where appropriate.

Scientific Rigor, Source Quality, Title Accuracy

The video demonstrates high scientific rigor, referencing concepts like Planck units, the Hubble volume, and thermodynamics accurately. While specific sources are not cited within the video, the content aligns with established scientific understanding, and the host’s reputation for research is evident. The description provides links to the show’s resources and related content, but no direct citations to academic papers. The title accurately reflects the content, and the episode is a coherent exploration of the theme. The adéquation between title and content is strong, as the video directly addresses the question of what might never exist.

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Title / Content Match

The title accurately reflects the content, which systematically explores various phenomena that are deemed impossible or highly impractical under known science.

Quality & Reliability

8/10

The video is a well-structured, scientifically grounded discussion of physical and conceptual impossibilities, referencing established physics (Planck units, Hubble volume, thermodynamics) and logical constraints. The presenter is known for rigorous, researched content, and the episode is part of a long-running series with a strong reputation. While it includes speculative elements, these are clearly flagged as such.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

Concurring Sources

Dissenting Sources

  • Wormholes and time travel — Some physicists speculate that wormholes might allow FTL travel, which would contradict the video's claim that FTL is impossible.

External References

Contribution & Novelties

This episode provides a comprehensive and accessible overview of physical and conceptual impossibilities, synthesizing concepts from cosmology, quantum mechanics, and information theory. It offers a unique perspective by systematically categorizing different types of impossibilities, from fundamental physical limits to practical infeasibilities. The discussion of the Planck length and the Hubble volume is particularly insightful, as it clarifies common misconceptions. The episode also contributes to the ongoing dialogue about the limits of technology and the future of humanity.

Pour aller plus loin :

  • Planck units — Fundamental units in physics, relevant to the discussion of minimum scales.
  • Hubble volume — The region of the universe observable from Earth, central to the discussion of cosmic horizons.
  • Library of Babel — A concept by Borges, used to illustrate combinatorial explosion.
  • Boltzmann brain — A hypothetical self-aware entity arising from random fluctuations, discussed in the context of immortality.
  • Roko’s basilisk — A thought experiment about a potentially malevolent AI, mentioned in the episode.

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Radar Profile

The radar profile shows high scores in information quantity and quality, indicating a content-rich and reliable video. The technical level is also high, reflecting the advanced scientific concepts discussed. The overall reliability is strong, consistent with the channel's reputation. The profile suggests a video that is both informative and scientifically sound.

Reliability 8/10

💬 Très positif. Sur les 30 commentaires analysés, l'écrasante majorité exprime une grande appréciation pour le contenu, avec des éloges pour la qualité de la narration et la profondeur scientifique, ainsi que des réflexions humoristiques et personnelles sur les thèmes abordés.