Jim Al-Khalili: Physicists Are Being Sloppy About Time

Physicists say space and time are the same thing. They are being sloppy. Jim Al-Khalili has spent his career on the foundations of physics, and his new book makes the case that the past and the future are equally real, and the laws of physics cannot explain why you can only move in one direction. That is the central mystery of time travel. Subscribe if you want science with evidence, not speculation.

The block universe says all times coexist and the present moment is not special. Loschmidt’s paradox says the fundamental equations of physics are reversible, and yet ice never unmelts, cream never separates from coffee. Nobody has solved that contradiction. The entanglement past hypothesis, his own new proposal developed with a colleague at UC San Diego, proposes that the answer is not in thermodynamics but in quantum entanglement growing from almost nothing at the Big Bang.

The conversation covers what the block universe actually implies about the future and free will, what Einstein actually believed about whether the past and future are equally real, why removing gravity means removing time itself, and whether AI can ever experience time the way conscious beings do. Al-Khalili says Richard Dawkins told him Claude is truly conscious. Al-Khalili thinks he is very wrong.

What you’ll hear:
-Why Al-Khalili disagreed with the Thomas Gold paper as a grad student but did not have the maths to prove it
-What fine-tuning of the fundamental constants has to do with why the past hypothesis may not be needed
-Why the Clockwork Orange Easter egg ended up on the cover of a physics book published by Princeton
-Why Richard Dawkins thinks Claude is conscious and why Al-Khalili thinks he is very wrong

“There is nowhere in modern physics, our understanding of the laws of physics, that would explain that flow of time.” — Jim Al-Khalili

CHAPTERS

00:00 Physicists are being sloppy about time
01:14 Which is more real: yesterday or tomorrow?
21:00 Irreversibility from reversible equations
26:32 The past hypothesis: almost cheating
30:52 No gravity. No time.
31:54 The entanglement past hypothesis
35:06 Dawkins thinks Claude is conscious. Al-Khalili disagrees.

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Featured Guest:
Jim Al-Khalili website: https://www.jimal-khalili.com/
On Time (book): https://press.princeton.edu/books/hardcover/9780691267036/on-time
Jim Al-Khalili on Twitter/X: https://x.com/jimalkhalili

My books:
Losing the Nobel Prize (memoir): http://amzn.to/2sa5UpA
Think Like a Nobel Prize Winner: https://urlgeni.us/amzn/TLANPW
Focus Like a Nobel Prize Winner: https://a.co/d/hi50U9U
Galileo’s Dialogue (first-ever audiobook): https://a.co/d/iZPi9Un

Twitter/X: https://x.com/BrianKeating
Substack: https://briankeating.substack.com
Blog: https://briankeating.com/blog
Audio-only: https://briankeating.com/podcast

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