From Doctor Who to Rick and Morty to Star Trek to The Twilight Zone and many, many others, we have lots of stories about time standing still. But does that idea actually make sense, and what would it be like if it did? There seems to be an intimate connection between time and change. One way that philosophers think about change is to say that objects have properties and then they have different ones, and that use of the word ‘then’ means that we must be talking about time here. In most of the fictional stories where time stands still, the protagonists notice because everything around them is frozen i.e. not changing. In fact, it’s tempting to just wrap this question up here and say that time is change. And a cursory look at
physics might support that idea. The smallest interval of time that we can measure is the time it takes for a photon of light, which is the fastest thing in the Universe, to travel across the smallest measurable distance, which we call a Planck length. In school you probably learned the equation speed is distance over time, which if we rearrange it gives us time is distance divided by speed.
One Planck length is roughly 1.6 x 10-35m, which is way, way smaller even than a proton. A Planck Time is the time it takes a photon to travel that far, which is very fast: 5.39 x 10-44 seconds. That’s zero, then forty-three more zeroes, five three nine The smallest measurement of time that makes sense. And interestingly for us, that smallest interval of time is a measurement of change – the change in position of a photon. If time were to stop then photons couldn’t be moving. Which means you wouldn’t be able to see anything because no photons would be entering your eyes. And everything would be very, very cold because no molecules would be vibrating, and molecules vibrating is what heat is. You also wouldn’t be able to breath or move, because the air around you can’t move. And you also wouldn’t know this was happening because your brain would be frozen too. If you were just moving really, really fast, faster than everything else, like the Flash, then you would perceive that as everything else moving more slowly, which would be kind of like time almost stopping. But if all the molecules around you were slower than you that would mean you were much hotter than them because temperature is just mean kinetic energy. Even assuming that that temperature differential didn’t kill you, your own heat would leak into your surroundings causing them to begin speeding up anyway.
But from physics to Physics, The Physics: Aristotle’s book, Physics. In it, the famous Greek philosopher notes the connection between time and change, but he doesn’t think they’re the same thing, because change, he says, only happens in the thing that changes, whereas time is everywhere. Change can occur faster or slower, and faster and slower are measurements in time, not of time. So Aristotle thinks that time is what we measure change with, just like space is what we measure size in. But…well, sorry Aristotle, does change only happen in the thing that changes? Surely change is just as much in the relation between the thing that changes and everything else? Doesn’t everything change relative to something, even if it’s just the other parts of itself? And even more seriously is change something that occurs within the passage of time? I wanna float a contrary idea here and say that it doesn’t make sense to talk about time stopping because time was never moving to begin with.
You Are Not HERE
We’re gonna have to make a quick detour here to talk about the Universe. All of it. Philosophers of time distinguish between A-Universes and B-Universes, and we’re gonna need to understand this distinction. An A-Universe is more or less how we’ve been imagining it so far. Time passes in an A-Universe. There is a definite past, present, and future and time flows like a river from one into the next. In a B-Universe, time doesn’t pass. And it’s less like a river, more like a swimming pool. The best way to explain is with an analogy to space and the word ‘here.’ I am here in my room and you are there wherever you are, but there is no property of ‘hereness.’ We could do endless scientific tests in both locations but we wouldn’t find any particles or anything that would explain why this place is ‘here’ and your location is ‘there.’ And that’s because the word ‘here’ is what philosophers call an indexical, a word whose meaning changes depends on who uses it.
For me, my bedroom is here and your location is there. But for you it’s the other way around, and that’s not a contradiction because that’s just how the words work. So in a B-Universe where time doesn’t pass, ‘the present’ is works like the word ‘here,’ an indexical, and ‘past’ and ‘future’ are like the word ‘there.’ ‘The Present’ just refers to the bit of time where we are, but in fact all times exist equally. Earlier on we said that one way of thinking about change is to say that objects have properties and then they have different properties. And some philosophers, notably John McTaggart, who invented the distinction between A-Series and B-Series, said that if you’re a B-Theorist you can’t explain change.
The B-Theorist account of change is to say that objects have temporal parts. So imagine that there’s a hot pie that’s cooling down. There is an earlier bit of the pie that is hot, and a later part of the pie, which is cool, but the B-Theorist says that the pie as a whole is an object that exists across time, a 4D object. To us, it looks as if the pie is changing but that’s just because we’re looking at a different part of it. And McTaggart doesn’t buy this, he sats that isn’t a description of change anymore than you could say that the text of a book changes as you read it. It doesn’t; you’re just your looking at a different part of it. And McTaggart wasn’t the only philosopher to say that we need time to pass for human ideas to make sense. A.N Prior talked about the sentence, “Thank Goodness That’s Over!” If I go to the dentist and have a really painful surgery and I say, “Thank Goodness That’s Over!” Prior says that sentence doesn’t make sense in a B-Universe, because it’s not really over, it’s just located at a different time.