Ye Cannae Change the Laws of Physics • Kevlin Henney • GOTO 2025

Kevlin Henney delivers a thought-provoking and entertaining talk that bridges physics and software engineering. The presentation is well-structured, moving from a playful introduction to deeper philosophical and technical insights. Henney’s argument that software is ’executable fiction’ is compelling, and he effectively uses examples like FizzBuzz to demonstrate how mathematical abstractions (infinities) are not physically realizable. His discussion of Lehman’s laws and the inevitability of complexity is grounded in established research, adding credibility. The critique of ‘velocity’ in agile is sharp and relevant, highlighting a common misunderstanding. However, some points are presented with rhetorical flair rather than rigorous evidence, such as the claim that ’the universe is physical, not mathematical’—while philosophically debatable, it is presented as fact. The talk also touches on the CAP theorem and relativity, but these are not explored in depth, which might leave some audience members wanting more. The inclusion of references to primary sources (e.g., Lamport’s paper, Brewer’s conjecture) strengthens the talk’s reliability. The title is catchy and accurately reflects the content’s focus on physical constraints. Overall, the talk is valuable for software practitioners, encouraging them to think beyond code and consider fundamental limits. The main weakness is the occasional oversimplification of complex physical concepts, but this is acceptable given the talk’s scope. The speaker’s expertise and engaging delivery make this a worthwhile watch.

The title is a playful reference to Star Trek, but the talk genuinely explores the constraints of physics on software development, making it apt.

8/10

High credibility: speaker is a recognized expert, talk references established concepts (Lehman's laws, CAP theorem, relativity) and provides links to primary sources. Some claims are anecdotal or metaphorical, but overall rigorous.

• 00:00Intro
• 02:48Physics
• 04:40FizzBuzz
• 13:13Work
• 17:14Roadmap
• 20:40Business value
• 26:17Speed of light
• 34:49We need to think of time as a resource
• 44:11Outro

• 97 Things Every Programmer Should Know - Thing 84 — Referenced in the context of software development wisdom.
• Kevlin Henney's about.me — Speaker's personal page.
• On the Reality of the Quantum State (arXiv) — Referenced in the context of physics and reality.
• GOTO Conferences on Bluesky — Conference's social media.
• Kevlin Henney on Bluesky — Speaker's social media.
• Software Development Roadmap (devm.io) — Referenced in the context of software development roadmap.
• GOTO Copenhagen 2025 — Conference website.
• GOTO Copenhagen 2025 Session — Specific session page.
• GOTOpia — GOTO's community platform.
• GOTOpia Newsletter — Newsletter sign-up.
• Kevlin Henney's Medium — Speaker's blog.
• Time, Clocks, and the Ordering of Events in a Distributed System (Lamport) — Referenced in the context of time and distributed systems.
• Kevlin Henney on LinkedIn — Speaker's LinkedIn.
• Great gaffe in the sky: the erroneous physics behind the dark side of the moon — Referenced in the context of physics misconceptions.
• Brewer's Conjecture and the Feasibility of Consistent, Available, Partition-Tolerant Web Services (Gilbert & Lynch) — Referenced in the context of the CAP theorem.
• GOTO Conferences on LinkedIn — Conference's LinkedIn.
• GOTO Conferences YouTube — Conference's YouTube channel.

• Lehman's Laws of Software Evolution — Supports the claim that software complexity increases over time.
• CAP Theorem — Supports the discussion on trade-offs in distributed systems.

• The Unreasonable Effectiveness of Mathematics in the Natural Sciences — Contrasts with the speaker's claim that mathematics is not fundamental to the universe.