Emily Adlam: Reality Is a Completed Puzzle, Not a Flowing River

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Previously titled “The "All At Once" Universe Shatters Our View of Time” — renamed by the publisher on Aug 3, 2026

Theories of Everything with Curt Jaimungal 1h 18m 3 speakers 8 chapters transcribed 22 days ago
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What is the “all‑at‑once” view of physics and why does it challenge the usual time‑evolution picture?

Emily Adlam 0:00
The dogma I worry about is that we should think about physics in terms of time evolution. This picture where you start at the beginning and evolve forwards in time. That's a very intuitive way of thinking about physics, but it is very clearly not a good fit for what we are seeing. There's really good evidence coming from lots of different parts of physics that we shouldn't be thinking about time in those terms.
Curt Jaimungal 0:21
Imagine a completed Sudoku puzzle. The rules don't dictate that you start in one corner and then work systematically across the grid. Instead, they just constrain what patterns are valid for the entire puzzle. Professor Emily Adlam of Chapman University suggests that the fundamental laws of physics work similarly. You don't evolve the universe step by step from past to future. Instead, there are these constraints something that selects valid patterns across. Across all of space-time simultaneously. This quote unquote all-at-once perspective helps explain paradoxical quantum phenomena like delayed choice experiments and Bell non-locality. It also comports with Einstein's relativity, where the distinction between past and future depends on the observer's reference frame.
Curt Jaimungal 1:03
If correct, this paradigm shift would transform our understanding of causality, of observers, and of the nature of physical law itself. What's the largest unsolved problem in physics today that you're interested in?
Emily Adlam 1:17
Uh well this is not a very original answer, but I think the measurement problem uh of quantum mechanics for me still really stands out as an important unsolved problem. Um And not just because it's sort of intellectually interesting, but because I it seems to me that it's closely linked to a variety of concrete problems that we're working on in modern physics. So in particular, I think in the context of work on quantum gravity, a lot of the issues we're really sort of struggling with are ultimately to do with the nature of observers, the nature of observation. Uh so for example, solving the problem of time is all about trying to understand uh how to put the observers into their theories in the way that reproduces the kinds of observations we expect to see.
Emily Adlam 1:56
And so that makes me think that uh perhaps there's an issue here where we never really came to grips with how to think about observers in the context of ordinary quantum mechanics. And that's really holding us back from making us progress on on further physics. So I think that problem to me demands a solution not just for intellectual curiosity, but also to be able to make real progress. And what's the definition of observer?
Curt Jaimungal 2:18
Is it the same as a measuring device or what counts as a measurement?
Emily Adlam 2:21
Well, that's exactly the problem. We don't we don't know clearly how to define observers in concrete physical terms. We have, of course, an intuitive notion of what an observer is, and we know what what we expect observers to see, but uh it's still very unclear how to properly model observers within quantum mechanics. All the interpretations of quantum mechanics say something different about how you should represent observers, and that has important knock-on effects for how. how you're gonna think about observers in the context of further physics like quantum gravity.
Curt Jaimungal 2:53
How does the problem of observers or defining what observers are have anything to do with quantum gravity?
Emily Adlam 2:59
So, I mean, one of the big problems we encounter in the formulation of quantum gravity is known as the problem of time, which refers to the fact that uh if you impose a sort of canonical quantization on gravity, the result is that time evolution seems to vanish. You h end up with this sort of strained timeless model. And so then one obvious problem you have is try to to try to understand uh how the kinds of experiences that we have could possibly arise in this context. Where does our sense of doing things in time and obtaining outcomes come from? And so there are lots of interesting ideas around this, but a lot of a lot of this is still very focused on this question of how exactly should you represent an observer?

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