Is the universe really infinite? | George Ellis and David Deutsch

David Deutsch defends infinity against George Ellis

The idea of infinity may make us feel a little giddy, yet we refer to it frequently as if it is understood. Mathematicians claim Georg Cantor cracked the puzzle in the 19th century and enabled us to understand and handle infinities. But is this perhaps a profound mistake? The writer Jorge Luis Borges argued 'infinity is a concept that corrupts and upsets all others'. And now some physicists are arguing infinity is the greatest crisis facing physics, claiming that it generates nonsensical answers in quantum mechanics and undermines all prediction in cosmology. Should we seek to remove infinity from accounts of the universe and rely on the finite alone? Or is infinity a key insight into the character of the universe, however difficult it may be for us to comprehend?

#DoesInfinityExist #PhysicsUniverse #CosmologyInfinity

Oxford maverick physicist David Deutsch, leading cosmology theorist George Ellis and theoretical physicist and origin of life expert Sara Walker debate whether the notion of infinity is a key insight into the character of the universe, a mathematical artefact, or simply nonsense. Hosted by the renowned public intellectual, writer and producer Robert Lawrence Kuhn.

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[lylecosmopolite]

George Ellis was a PhD classmate of Stephen Hawking. Ellis, Hawking and Barrow wrote their theses under Dennis Sciama. Ellis is less well known than Hawking or Penrose or Guth, but deserves to be better known.

[ak-lute]

It's time well spent to read Deutsch's chapter on infinity in The Beginning of Infinity. His point: That "experiment can never prove anything; it can only disprove at best, and it can explain. Those are the two criteria by which we need to judge science." The Fabric of Reality and The Beginning of Infinity are essential reading.

[ChuckSilva]

David Deutsch has such an amazing intellect combined with his delightful disposition. I too hope there's more of this to come. Thank you!

[cuddywifter]

Ellis is making a category error.

The block universe model if it exists, is an explanation of relativity & quantum theory. Where the age of the universe is only measured relative to a particular now within that block.

[winsomehax]

If you accept it had a beginning... that's a pretty solid argument against infinity. I'm not a mathematician or a scientist, but I do think that if "infinity" pops up in your calculations, . something has gone wrong. And mathematics that has "there exists an infinite set" in its axioms has gone badly wrong right at the beginning

[CONNELL]

This was the first difficulty I encountered when thinking about the Universe in my youth: If the Universe was finite, I thought, then one could think of a wall being built around its border (in my naivety I actually imagined a brick wall 🤣). But what was on the other side of the wall? More space obviously. But this immediately suggested an infinite number of similar walls further out. I remember feeling distinctly uneasy about this conclusion - very disorienting indeed!

[rainblaze.]

Isn't this just semantics?
If the universe expands forever ( and at C) doesn't that then mean it is by all possible "ends" infinite. Whether block or otherwise any result would nesseserly still be the same. Its like arguing how many angels can dance on the head of a pin

[Phillv]

Falsifiability alone should not be leveraged in order to decide whether or not our universe is actually infinite, and for the same reason that it should not be used to decide whether or not the universe began, all as it seems, 2 hours ago.

[Rasenschneider]

If the universe is infinite it is not only infinite big but also infinite small within space and time or spacetime. That seems possible only if matter only exists as a concept

[CometComment]

I'm glad I wasn't the only one shouting that science cannot prove anything.

[clemsonalum]

I found it frustrating to listen to Ellis, it felt like semantics. In the block universe model, the 13.6 number is irrelevant, its only the number in our present but our present is irrelevant. The question then becomes, is the block universe infinite or not. Its fine if he doesn't believe in the block universe, but he was trying to have it both ways. If you believe we are expanding and time is real, then you don't believe in the block universe. The whole point of the block universe is that time is an illusion, and 13.6B ago, now, 13.6B into the future, etc etc are all just as real as the other.

[rayhan]

Deutsch is unparalleled ... Please tell me their is a full hour+ long conversation of this.

[PMKehoe]

Some people in the attempt to ‘explain’ or ‘engage’ with the concept of ‘infinity’ premise the rhetorically semantic over math, the theoretical AND some do the reverse, giving credence of math/geometry over the semantic/the definitional - to begin with…

[theuniques]

The Universe repeats itself verbatim because only a reproductive state is absolutely an infinite state(unchanged state), the Universe(eternity) is the origin story(human consciousness) of itself(the Universe, eternity, space, existence), the Universe always knows itself as proof of itself. I always have and I always will write(rewrite) this same exact comment. Repeat is eternity as eternity is repeat, the Universe always reprojects this same exact image of itself because space(existence) can never be an object of itself as the eternal present moment.

[chrisponsano]

David knows the difference between potential infinities and absolute infinities. So why argue with George Ellis? You can never prove that there is anything both physical and absolutely infinite.

[HigherSofia]

Wonderful! Looking forward to the full version.

Appears as silly semantics to say the universe has a boundary. That's just excluding the primordial emptiness surrounding the physical Universe. Ofc, he may be right that its expanding and has an age and boundary.. that specific expanding Universe will never reach Infinity, but who in the hell gave anyone the right to separate the primordial emptiness out of the Universe.. Stop doing that. It's just silly.

[readynowforever]

🙂 Must we argue about the small things…why can’t we meet at a contextual exegesis, of:

“infinitely growing—expanding universe” ?

But not infinitely existing.

[markberman]

Infinity, like time, has a start and an end date. A universe can be infinite, but still be bound by time. Yes, this seems illogical and self-canceling but it is not. We need the concept of Infinity to do some maths within our universe. There can be infinite possibilities, but only one course. And a probability matrix needs infinite possibilities in order to produce what is being worked out.

[smlankau]

Each point in space is relative, and time would make more relative points infinitely. Space and matter was very large, and they couldn't fit into a small singularity.

[leonardooliva]

It seems that George understood a substantial point: infinity is beyond our intellect (and related things such as methods and tools).

The book THE GREAT SYNTHESIS solve all problems of today science.