Archive: All the time in the world

Originally posted 9 May 2005. My view shifted less than a year after writing this, when I came across Julian Barbour's The End of Time.  Still, this was a step along the way. I guess my present view isn't far off what is expressed here briefly as 'Presentism'. But in another sense it is a special case of a B-Theory, with no 'real' flow of time.

I have for some time held a 'Block' view of time, without realising that it had such a name. Upon thinking a bit more about time, I realised that my view on it is so closely entwined with my views on personal identity, determinism and morality that I really should make it a matter of record.

The Block view at a glance
By a 'Block' view of time, I mean this: that time can be seen, within limits, as a space-like dimension that, when visualised in conjunction with the three spatial dimensions, creates a four-dimensional 'Block' of spacetime. This Block is the vessel that contains the complete history of everything - or simply IS the collection of all histories - in our universe. If space or time is infinite (as it now seems at least space is), then this Block too is infinite. This, I think, is the standard scientific view of time, and four-dimensional spacetime is the stage on which Einstein's general relativity is set out.

But there are potential problems with this. From a scientific angle, at least one of the leading candidate theories of quantum gravity - the required next big step in reconciling relativity with quantum theory and advancing our understanding of the universe - does away with spacetime altogether. From a philosophical perspective, some say that such a view fails to account for the flow of time.  Leaving quantum gravity for another time, I'll concentrate hear on the philosophical issues.

My Block view falls under the umbrella of what is known as the B-Theory of time. There is another set of theories that fall under the A-Theory umbrella. Essentially, I think that the key differences are these:

A-theory and B-theory of time
The A-theory believes that the flow of time (temporal becoming) is real, objective and absolute. NOW is a moving instant that flows at one second per second. The A-Theory also believes that the temporal properties of futureness, presence and pastness are real temporal entities. A specific version of the A-Theory, Presentism, denies the existence of past and future, leaving only the eternal NOW. See my post on Eckhardt Tolle's The Power of Now.

The B-Theory holds that past and future events, like present ones, are real. As a matter of fact, B-Theorists hold that, just like there is no objective special place called 'here', there is no objective special time called 'now'. There are just points in the temporal dimension at specific dates and times, and the only real temporal entities are the temporal RELATIONS of earlier than, later than and simultaneous with. The image is one of a time axis on which we can see that some points lie to the left of (and are hence earlier than) other points.  But the thing to grasp is that events that lie to the 'left' and 'right' of the time we presently occupy are just as real (at those times) as the events we witness now. And it goes further.

The philosophers discuss time mainly by talking about the truth of statements about temporal relations. For B-theorists, if my mother kisses the US President at 12:30 pm on 5 December 2003, then the statement, "D's mother kisses the US President at 12:30 pm on 5 December 2003," is true not just at 12:30 pm on 5 December 2003, but eternally. Eternally in this sense does not mean 'at all times' but rather timelessly. That truth, like the truth 2+2=4 does not exist in time at all.

A closer look at the Block view
But talking about truth values of statements doesn't do it for me.  I want to talk about the existence of things and events.  I am drawn, and have been since long before I read about the philosophy of time, to an image of spacetime, as seen from a perspective OUTSIDE spacetime. Of course, such a perspective cannot be attained, but we can think of it as a God-like one. From outside spacetime (and therefore necessarily outside time), we 'see' a four dimensional container, and that container holds the entire history of every particle, field and every other entity. If we were to pick out a single rock, we could follow it along the time dimension (which, since we can't visually represent 4 dimensions very well, we might think of as going from left to right) and see that it's spatial position shifts (up, down, etc) as it moves 'forward' through time.  Now, I've said we can imagine this God-like perspective, but the more important point is that this is how things are, although we cannot attain the proper perspective to see them this way.

Just as the philosopher says that the STATEMENTS 2+2=4 and "D's mother kisses the US President at 12:30 pm on 5 December 2003," ARE TRUE eternally, I believe that that rock and everything else within the spacetime 'container' (or collection) EXIST eternally. Once again, this isn't to say that they exist at all times; if we say that we are still thinking within the time dimension. The Empire State Building came into existence at a particular time and will no doubt cease to exist at some time. It is rather to say that anything that exists at ANY TIME, exists eternally, timelessly, from this God-like perspective, outside of the time dimension.

This visualisation I've used also helps show the main objection that B-theorists have with the A-theory: there is no special time in this 'vessel' labelled 'Now'. Time is just a fourth axis for the grid system.

But this simultaneously throws up the big problem that A-theorists have with B-theory: it doesn't adequately account for the Now-ness or presence of certain events. The vessel is filled with events, but why do some specific ones feel very different than the rest, i.e. why do they feel like they are happening NOW. B-theorists answer, once again, more in terms of the truth value of temporal statements rather than about events / things per se. But I am quite happy to take it that the events that are happening NOW as opposed to at some other time are those events that are near-simultaneous with my asking 'Which events are happening now?' Events that happened in the past are those that happened earlier than my asking that same question, and future events are ones that happen later than when I ask the question.

What makes time unique among spacetime dimensions?
But this does highlight another problem that many B-theorists have with my particular Block time version of there own theory. Time is obviously not a truly space-like dimension.

• First, whereas we can draw three axes to represent the space dimensions and orient these axes however we like (so as to look 'normal' to an observer looking from any direction), the time axis seems to demand a particular orientation. We can't imagine tilting it at 30 degrees clockwise or spinning 25 degrees to the rear.
• Second the time axis has a strict direction of succession, always heading 'forward' in time. Contrast this with my ability to move either up or down, left or right, backward or forward in space itself.
• Finally, although the spatial dimensions extend vastly all around us for our inspection, in the temporal dimension, we have sensory access to only a moment at a time, access to the past only by memory, and no access to the future at all.

This is where the real mystery comes in, and perhaps it is a particular weakness in my theory that leaves me in this cul-de-sac having to throw up my hands and appeal to mystery...  But I haven't seen anyone else bottom it out yet either.

We could say, and many philosophers do, that it simply is the case that the temporal dimension is qualitatively and irreducibly different from the spatial ones - objectively. Or we could say that it is not that different objectively but that there is something about the nature of sentience and consciousness that makes our inter-subjective experience of it seem different.

If we're willing to accept one of these explanations, what are the knock-on effects? Well, on my view, accepting the Block theory of time answers the free will / determinism debate once and for all. Although such a theory of time is not necessary for determinism to hold (an A-theoretical flow forward from a set of initial conditions according to fixed and determinate laws does the job as well), I think it is definitely sufficient. If all of history is captured in spacetime, with us just consciously 'riding' through the time dimension, then everything we do, we do necessarily.

Eternal life?
I think that the block view also prompts interesting questions about sentience and consciousness, life and death. If all that exists does so eternally, and if the flow of time is simply something that we experience subjectively, then are we not eternally living those lives?

When I die as when I live, all of the moments of my life exist in that four-dimensional spacetime; if that window that moves along the time dimension, providing access to the 'present' as it rolls forward, is not objectively in the nature of the temporal dimension itself but rather in our experience of it; if no moment in time has a privileged position relative to all the others, then I live my life, from 16 June 1966 to the day I die, eternally.

That doesn't mean that I live my life over and over again. It doesn't mean retracing and taking different turns through supposed possible worlds, as it is always exactly the same. But it could mean that my subjective experience itself (or perhaps more exactly each and every moment of it) runs eternally between those two points on the timeline.  My first sentient experience (probably even before birth) exists eternally.  My last dying experience exists eternally.  And so does every experience in between.

Maybe the whole history of the entire universe sits, still and unchanging, four dimensions. Maybe the only movement is the eternal subjective movement of sentience between the start line and the finish line of each sentient life in the temporal dimension. And the existence of that sentience, that subjective perspective, is just something that happens to be, arising from the relations among entities in that four dimensional space...

If so, then Nietzsche wasn't far off with his doctrine of the Eternal Return.  Although he saw eternity as a never ending looping repeat of history, which is quite different from what I've spelled out, the recommendation is the same: live each moment of your life as if you will live it eternally.  See my post on Nietzsche here.