The Space-Time Continuum

Sunday, October 13, 2019
First Aired: 
Sunday, April 2, 2017

What Is It

Strange things are said about time: that it's illusory, that it has no direction. But what about space, or the space-time continuum? What exactly is space-time? Are space and time fundamental features of the world? How do Einstein’s special and general theories of relativity change our understanding of space-time? Is there a distinction to be made between space and time, or must the two concepts be united into a single interwoven continuum? John and Ken expand their space-time with Tim Maudlin from NYU, author of Philosophy of Physics: Space and Time.

Part of our series A Philosophical Guide to the Cosmos.

Listening Notes

What is space-time? Space has three dimensions and time has before and after. John sees space and time as independent of each other. Ken adds that common sense dictates that space and time are absolute things. Time, he says, contains the entire spatial manifold which moves through time as a single unit. Leibniz said this was incoherent and violated the principle of sufficient reason. The philosopher claimed that there would be no discernible difference between one position in absolute space and another. The idea of absolute space, Leibniz claimed, is an empty one. The due talk about the speed of light and its role as the measuring stick of the geometry of the universe, and try to get at what space-time really is.

John and Ken welcome guest Tim Maudlin, Professor of Philosophy at New York University and author of Philosophy of Physics: Space and Time. John asks Tim what drew him to study the philosophy of space-time rather than the physics of the matter. Tim explains that in undergraduate, he studied both philosophy and physics, and in both cases he was driven by the intellectual desire to get to the bottom of things; the conceptual side of things, however, appealed to him more. John wonders whether it makes any difference if space and time are two separate things or just a single entity; Tim explains that in everyday life it doesn’t, but if the theory of relativity holds, then the fundamental structure of things – that we all enjoy the very same moment – is shaken up. Ken asks whether each place in space has its own time. Tim explains that the measure of time is the measure of the path you are traveling through space-time; different paths have different lengths. Is there empirical information back the theory up? And if Leibniz were right, wouldn’t quantum mechanics be wrong?  

Ken wonders what philosophy has to contribute to the debate of space and time. Tim explains that philosophy’s contributions in the field of space and time come more from philosophical training than from philosophical doctrine.  Philosophy forces you to think about the very bottom of things, the fundamental, conceptual level and try to get extremely clear and precise about the fundamental concepts. That is absolutely necessary when you’re doing foundational work in physics, Tim explains! What’s not so clear is the relation between mathematical models and physical reality. And isn’t time just change? Does time have direction? John, and Ken welcome questions from the audience, and they continue the discussion.

  • Roving Philosophical Reporter (Seek to 7:30): Philosophy Talk's Reporter Shuka Kalantari investigates the paradoxes of time travel in movies and shows like Back to the Future (the pre-destination paradox), The Butterfly Effect (the aptly named butterfly effect paradox), and Dr. Who (the bootstrap paradox).

Comments (3)

Harold G. Neuman's picture

Harold G. Neuman

Thursday, September 26, 2019 -- 12:29 PM

Time may well be illusory. Or

Time may well be illusory. Or, it may have no direction. Equally, the space-time continuum, relative as it is to homo sapiens sapiens, also, as a practical matter, is illusory &, well, relative. We notice these things, i. e., we think about them, because we can and because we need to believe that anything that may affect us needs to be analyzed, ad nauseum, or even more so. Astro-Physicists and Cosmologists need something to occupy their TIME; they need to feel secure about their place in the biggest possible picture human society . Also, and perhaps more telling, if we should ever understand any and all branches of physics; if we should ever be able to fully utilize these things which are now only topics for discussion and conjecture, the stuff of science fiction (or more of it) could be within our reach. Imagine if space-time continuum actually meant something we could manipulate, if only in small ways (whatever those might be...). Admittedly, this is mostly speculation. But, thinking about it, that is how many of our realities arrived. They grew out of speculations. And, surely, as philosophers, we speculate daily. Jumping outside of the space---this is what we are all about...
The only things we can never know are those about which we have no curiosity. A totality of the circumstances...or something like that.

Harold G. Neuman's picture

Harold G. Neuman

Wednesday, October 9, 2019 -- 11:20 AM

This morning, I was getting

This morning, I was getting coffee from my favored quick stop. I saw an individual whom I recognized as having made some news, locally, with research into the notion of time travel. I asked him how his work was going: had he figured out the old space-time continuum conundrum? He said he (and unnamed collaborators) were getting close; mentioned something vague about an upcoming press conference; and also said the Australians were making headway but were 'way behind what we are doing'. Now, I'm not one to pooh pooh scientific progress: I like to think I might know it when I see it...sometimes even occasionally predicting a thing or two, myself. But, this man has been kicking this around for a number of years. He is animated when talking about time travel, one might say: driven. I know no one else who knows him and most people of repute, with whom I have spoken, roll their eyes some when his name is mentioned. I'll not mention his name here, inasmuch as my revelation about him is not glowing and might even be considered insultatory.

But, allow me to be clear. He was knowledgeable regarding the likes of Sean Carroll; the late Stephen Hawking and others. I sincerely hope he is on to something (whether on his own or with collaboration). Think of it: time travel! Wouldn't that be grand? Sure. But, I won't take any bets on it. Just yet. Oh, he did mention that he had little time for philosophers---thought that they spent far too much time arguing with one another; that their professed search for truth was a con. They ARE a fussy lot sometimes. But, aren't we all?

RepoMan05's picture


Friday, October 11, 2019 -- 6:32 AM

It's the speed at which space

It's the speed at which space is created by bending it out of itself. It's an expanding bubble created by relevance.