Simon Saunders: The Unsettling Mysteries of Time

**SPEAKER_1** (0:00)
Heat up your 4th of July at The Home Depot with our wide variety of grills under $300 and make every gathering one to remember. Give your outdoor space a glow-up, whatever your budget is, with savings on seasonal plants starting at $5.
With the grill fired up and your backyard set to perfection, you'll be able to invite friends and family over to kick off the party. Start celebrating with low prices guaranteed at The Home Depot. Prices may vary by store, using the pricey homedepot.com/pricematch for details.

**Simon Saunders** (0:30)
It doesn't feel as though time is passing. Where is time passing? Time remains the central concept in physics that is least understood. There's lots of debates in the theology, aren't there, about whether God exists outside of time. I think that's extremely interesting.

**Curt Jaimungal** (0:46)
Professor Simon Saunders, Emeritus Fellow at Merton College, Oxford, is one of the most celebrated philosophers of physics alive, working on what time actually is.

**Simon Saunders** (0:57)
I find it almost insane, all of the minutiae of our present existence, with all its craziness and insanity built in from the beginning of the world.
No, I cannot believe it. It is not necessary.

**Curt Jaimungal** (1:13)
On this channel, I, Curt Jaimungal, interview researchers regarding their theories of reality with rigor and technical depth. Today, we go deep into the philosophy of time and what any of this has to do with the many worlds interpretation.
We go over the professor's boldest claim that the violation of Bell's inequalities is not evidence against locality, it's evidence for the many worlds. We even touch on consciousness.

**Simon Saunders** (1:39)
I am just in my Everettian branch. You are in your Everettian branch. We can coherently treat ourselves as a sort of extended observer.

**Curt Jaimungal** (1:50)
Professor, what is time?

**Simon Saunders** (1:54)
Yes, the easy questions first.
Richard Feynman said something about time. He said this, he said, time is how long you have to wait.
You can't really say anything more than that, without getting into trouble.
It goes back to, I forget the name of the philosopher now, that said, time, if I have to, if nobody asked me what it is, I know perfectly well, but as soon as I'm asked, then I become deeply puzzled and so forth. So yeah, I mean, time, I think probably remains the essential concept in physics that is least understood. I think that's probably right to say. So at some fairly fundamental level, we, I think, do not altogether understand time. But we have very adequate representations of it in physics. And we know how to deal with it in our ordinary lives. But it is extraordinary. I mean, look, think of it in terms of just your life, whatever, you've lived perhaps only 20, 25 years, heavens, long enough. There are many, many hours packed into those years. Consider yourself in any one of those hours. There's time to think and comment and reflect and, you know, look around and so forth. This is you being you. This is you being a person living in an ordinary way over a period of, say, an hour.
But then there are thousands of such persons on that basis. Because there's been thousands of hours where you have lived through those hours. So, there's thousands of, call them larger than moments. I don't want to make it just something instantaneous. There are thousands of times of your life, persons as it were, considering themselves at the time to be all that they are, that there's nothing more to them. As I speak now, I'm not considering that there's more to me in the future.
So, I'm perfectly adequate as a person with my past, but then there are thousands of persons with my past going back in time. I'm one of those thousands. Of course, if we make it not an hour but a minute, we make it not a minute but a second, if we really compress it, you can have as large a number as you like of previous moments.
So, what is the status of all of those moments? I mean, how do we deal with that reality, that multiplicity of realities? Because each seems like a reality. You ask me what is real, I can't do better than just point to stuff around us and say, well, look, this is what's real, it's Johnson kicking the stone. So, they're all realities and they all somehow exist. Well, they don't all exist at the same time. They exist with a sequential structure and more than that, there's a causal structure and we build and build and build until we've got quite an elaborate understanding of that multiplicity as something fairly integrated. And yet, there remains something really problematic about it all. It seems that we ought to take all of those momentary me's as equally real. They're separated by intervals of time. They're not all simultaneous with one another, but it seems we must take them to be all somehow real. And this follows in particular from the theory of special relativity. To some extent, also general relativity, but GR brings in some extra considerations. But in special relativity, we learned that there's no such thing as a global present.