Philosophy for our times: cutting edge debates and talks from the world's leading thinkers

Time's Arrow:

Can physics explain the nature of time?

Welcome to iai tv. You are limited to 20 minutes of video a month without signing up. X
Membership is completely free, and gives you unlimited access to our videos, articles, courses and much more
Already a member?
You have used half of your monthly limit of videos. Sign up to continue watching. X
Membership is completely free, and gives you unlimited access to our videos, articles, courses and much more
Already a member?
You’ve reached your monthly video limit.

Want to see more?

Sign up to continue watching. Membership is completely free, and gives you unlimited access to our videos, articles, courses and much more.
Already a member? .
IAI TV videos are for personal use only. For commercial or educational licensing please contact TVF International
  • The Debate

    Time's Arrow

    Time appears to be the ultimate form of progress: an unavoidable direction imposed on the universe. Some physicists claim this is an illusion. How should we make sense of time? As a dimension, a flow, a place, a process, a social construct, or something altogether more mysterious?

    The Panel

    Physician, poet and thinker Raymond Tallis, philosopher and broadcaster Angie Hobbs, theoretical physicist Jim Al-Khalili, and philosopher of time Craig Bourne go in search of time's direction.

  • Find out more about speakers

Jump to what you want to see in the debate
  • Jim Al-Khalili
    The Pitch
    Celebrated physicist's case for the absolute nature of time
  • Raymond Tallis
    The Pitch
    Modern polymath dismantles time's arrow
  • Craig Bourne
    The Pitch
    Philosopher of time uncovers the mystery Now
  • Angie Hobbs
    The Pitch
    Plato scholar adds the dimension of ancient wisdom
  • The Debate
    Theme One
    Is science the right tool to understand time?
  • The Debate
    Theme Two
    Do we need alternative accounts of time?
Want to learn more about our speakers?
Join the conversation

to post comments or join now (only takes a moment). Don't have an account? Sign in with Facebook, Twitter or Google to get started:

Bo Nyberg on 23/07/2015 10:01pm

I think the version of presentism as described by Craig Bourne and seconded by Jim Al-Khalili, and also to some extent by Raymond Tallis, may have a point... Compare to my own ideas on

deeboyy on 05/07/2015 9:02pm

naeem that seems a reasonable point. based on my rather limited understanding i think that that would also fit einstein's 'time' too? if everything just came to an absolute standstill at the subatomic level.. photons and all that shit.. then time would just cease? would the strong and weak nuclear and electromagnetic forces just cease too or could they exist without matter? or do they need matter? i wish i was intelligent enough to understand the books.

at the risk of sounding more daft when on films/tv lol somebody stops time haha it's always represented as people just becoming frozen.

i also think that einstein's theories are taken as gospel by all physicists and it's dangerous. i'm sure that they'll be thrown out at some point.

JRDAGO on 07/01/2015 1:52pm

Thanks for providing the nice talk, “Time’s Arrow”. It was for me very interesting listen to good explanations about time as flexible, sliceable, relative, chronometric, elastic, linear, present, past, future, etc.

Possibly one day it will be demonstrate hypothesises with many others characteristics about time and maybe also they will consider that time is the link among Earth’s biodiversity, minerals, atmosphere, our minds and going further interacting with the Cosmos.

Perhaps time is the universal diversity of things linking all possibilities and dimensions.

But, I still have questions about time’s concepts. For instance, if time could interfere in the means we create a pragmatic life or philosophy about it.

I would like to use the possibility in time being the links between all events happening in Earth, for exemplify some possible dissonances when we structure our minds.

This is just a simple hypothesis I imagined about our way to control time which might be the reason for our detachment from other living forms in the planet and also the principal motive we are destroying Earth’s natural resources.

I think that the sense we create about controlling time started in the distant past when we discovered how to cultivate food, instead of just harvesting it from a natural environment.

So, dreaming about controlling time, through controlling Nature, may well be in our minds for thousands of years.

It’s possible to imagine the great surprise when we notice that something apparently ends up happen in Nature under our mastering.

That probably was our first step to interfere intentionally on the biodiversity existent in Earth.

Probably at beginning this practice was something almost inoffensive for Earth’s environment and for thousands of years apparently it didn’t aggravate anyhow the situation.

But for illogical reasons, our attitude got a drastic transformation on last centuries, from a very simple thing it was seeding soils, which normally gave us in return life, it transformed into something very destructive in terms ecologic.

We could carry on talking about the kind of destruction happened, considering economics and sciences, but what I would like to point out are the reasons made us insensible and lose the track about Nature.

My supposition that it happened because our false notion in exerting high power over Nature.

Sorry, of course we can exert high power over Nature but unfortunately it only produces desertification.

When and how we lost the track?

I think that it started to happen at the moment we accelerate the process to produce food, as we create machinery that works too fast, doesn’t giving time anymore for Nature rescue its resilience.

I imagine it isn’t necessary to give samples about the chaotic situation we create, but it may well be linked to the dissonance we generate between our idealized time in contrast to the cyclical time happened in Nature for billions of years, seasons after seasons.

It is obvious that we changed procedures related to time and probably the reason for it, is because we based our decisions on a structure of time experienced in a pragmatic world, where time runs in a linear progression. In a kind of world it can’t be found situations with cycles of life as it happens in Nature.

How catching the train another time?

I think that science from the beginning found its bases on philosophy and they together kept in many ways coherence, following a number of ethical discussions.

So, thinking about ecology, there are some problems to be solved:

a) we depend absolutely on Nature, but in other hand Nature would survive very happily without any of our interference.

b) we can’t copy Nature, because its processes aren’t until now deciphered by us.

c) we even need Nature in good shape in order to help us decipherer our owns processes of life.

d) we have more scientists, who are capable to study Nature working against it and incoherently destroying their source of knowledge, instead of helping it survive, for their own personal health and work benefits.

e) we should invest more time to sort-out sooner the controversial situation is happening, before Nature end up losing its total capacity to help us to live.

Maybe it could be figured out that we are using the natural source of power existing in Nature for making fake copies of it, to be kept on its place, like frozen false trophies for dreamers of time-control. Something dead with a nice façade as it could be alive forever.

Possibly the process we are living in is a construction of a pragmatic world that freezes on time and mistakenly it looks for us more reliable than the natural one.

So, I hope that this text somehow helps philosophers, scientists and others in general realize that is pure ingenuity converting, our way to sense or live in a natural time into a fake life just timed from inside an atom.

“In Nature time means be in balance. For time-controllers time means illusion.”

Gideon Moss on 07/11/2014 1:08am

I found this a bit disappointing in that it didn't mention the lack of direct measurability of time(this also applies to space). Time can only be measured as the interval between events; without events there could be no time as it just couldn't exist. This is presumably the case prior to the big bang. So time doesn't exist independently in itself as a temporal space which we can populate with events. The measurement is the measurement of non action, an absence of events. But consider the universe consisting of the first event which brings time into existence; presumably the most simple event is a quantum fluctuation of some sort. Until the next quantum fluctuation occurs, how can we theoretically determine that time is passing? There is nothing in existence, the universe has registered a single event but unless everything is brought into existence at the same time (the big bang) it would have failed.

Similarly space doesn't seem to be a measure of an independent quantity but only exists as the distance between objects and the most fundamental objects are really the events that is the existing of a quantum of matter/energy which is also a quantum fluctuation. Without the existence of the two events the space between them doesn't exist either.

So we can only talk of the position of an object with respect to another and the time of an event with respect to another. This is what Einstein means by relativity. It seems that Newton, for all his genius believed in an absolute space and time like a big set of axes in space. I believe it would have meant sense to Newton to talk about, say, the absolute region of space occupied now by a part of the sun which a certain time later might be occupied by his physical body if the absolute motion of the sun and Earth through the galaxy was such that it lay in its path. Similarly he would have thought that there was some absolute reference by which the present moment could be measured with respect to a fixed time of zero and that this was the same at all points in absolute space.

This seems rather naive to us now but it works pretty well most of the time. It should hardly be surprising though that taking one non directly measurable, unanchored quantity and measuring it with respect to another when applied to massless entity such as photons in the electromagnetic propagation of light yields the rather unintuitive constant c the speed of light which is somehow independent of all reference frames..

I find it puzzling that Maxwell didn't notice this and beat Einstein to the special theory of relativity.

Melon-Cauli on 18/10/2014 7:06pm

Could someone explain to me how the notion of a contraction might play into the nature of time?

I thought that, since the big bang, the enormous weight of the universe has been exerting a gravitational pull on the ever expanding mass. This implies that, one day, the energy expended in the expansion would no longer be able to resist this pull, and a contraction would occur.

What I'd like to find out is, is this contraction probable, and if so, what does it mean for time and cause generally?

Many thanks.

naeem214 on 12/08/2014 12:35pm

O' my concept of time was that its the change in physical events I thought if the whole universe became still even at subatomic level then there would be no time.... well it wouldn't matter.

T MM on 02/02/2014 12:39am

The Hubble expansion I.e. expanding universe, could be used as a common cosmic time indicated. See

Lucian on 17/10/2012 7:41pm

Hello Emilie

We're working on setting up user profiles in the near future, so watch this space!

On the limits of our understanding of reality through science and language, try The New Romantics with Iain McGilchrist, Henrietta Moore and Joanna Kavenna, and for a more poetic spin on how our metaphors and language construct our reality, Blinded by the Light?. Both of these can be found by searching for Philosophy from the homepage.

Emilie on 13/10/2012 2:46am

just clicked the linked time in my last comment and found the section again! So, my point: the woman seemed a little mad and I was not sure where she was going, but then it hit me. She's articulating that EXACT thing about time that is the best refutation of the physicist's claim to 'understand more about time than the philosophers' think we do'!

And that is this:- he's embedded within time. He's claiming to talk about time. But what he's saying isn't actually about time qua TIME - "actual" and not human time - it cannot be! She might not explain this so well, but the embedding within time problem is the exact issue of perspective that plagues all talk. We're embedded within talk, too, in language. Both physics and language are things that we can't use to talk ABOUT themselves!

Rather:- physicists talk and that talk reveals how a physicist thinks about physicist time. A philosopher talks and he does the same - except he's going to be inclined to refer to this limitation.

What does this tell you about philosophers? Clearly that they are more honest?

(unless... you think that the philosopher talking about time and the problems with talking about time is just another example of not actually talking about the limitations on philosopher's understanding of time, because he is embedded within that too...)

It's an infinite regress, potentially. If there are any debates here that can reveal a little more about those then that would probably be most useful at this point!

Emilie on 13/10/2012 2:30am

I found this and got quite excited about the contents of the second theme from 28:43, then when I signed up and logged in and tried to find the part I was interested agian by cliking on the 'Play from theme two' button, it kept skipping to the beginning music bit. Funky music though you do have, disrupt the user-experience it did!

So amid my confusion I feel less like commenting on the nature of time. Also, is it possible to set up a user account like on Because I like using that profile as a kind of accumulation of my past posts etc. I suspect it's the new form of social networking since the recent catastrophic decline of facebook and its sell-out conventional counterparts. Where's my profile? Where's my equally philosophically curious compatriots' profiles? And I want to respond to their comments specifically! User experience etc.

Cathy on 04/10/2012 4:15pm

Thanks Terminatrix, I've the very 1st iPad that came out !

Cathy on 04/10/2012 4:13pm

Great topic and well chaired by Quentin. I'm going away to find out if or why Zeno was an idiot!

terminatrix on 04/10/2012 3:28pm

works fine for me, i'm using the ipad 3

Cathy on 04/10/2012 3:17pm

Settled in to watch this as I'm a new member by 10 mins, but will have to watch another time as the sound is so faint. Full volume on iPad (95% charged)?but I can hardly can hear the debate. I have soundboard turned down to approx 2/3rds when viewingn on YouTube..

DavidandGoliath on 04/10/2012 1:15pm

I agree that there are lots of questions about time that physics people can't answer, but I'm not sure if they are even trying to answer most of them. The point of physics not to ask about how time feels, but instead about how we can understand it for the purposes of scientific theories. Like infinity - not something that we can even imagine, but mathematicians use it on a daily basis. Surely that's all the understanding of infinity that we actually need?

Copy and paste the code below to embed or link to this video.

Embed options
  • Video Seek
    Converted to a link which jumps to that point in the video
    Example: 00:34
  • Bold Text
    Example: [b]Bold[/b]
  • Italic Text
    Example: [i]Italics[/i]
  • Underlined Text
    Example: [u]Underlined[/u]
  • Website link
    Link to another website or URL
    Example: [url][/url]

Rate this talk with three clicks. You can choose 3 words, or vote for the same word 3 times.

Why sign up for the iai?
  • Discover new ideas
    Free and unlimited access to hundreds of hours of debates, talks and articles from the world's leading minds, as well as courses that rival top academic institutions.
  • Have your say
    Join the iai community and engage in conversation and debate around the issues that matter.
  • Hear it first
    Be the first to hear about our video releases, articles and tickets to our upcoming events.
Sign me up