Time and Time and Time Again

BIS Space: What is Time? GJ Whitrow

Where is the arrow of time pointing? Published by Thames and Hudson 1972.

Time passes.  We experience it continually, and it’s such a fundamental aspect of our lives that we take it for granted.  Yet Einstein’s revolutionary theories convince us that it’s just part of the space-time that arises from the gravity produced by mass in the universe, and varies according to proximity to massive objects.  Also, there’s no absolute direction to time, contrary to how we perceive it.

GJ Whitrow, then Professor of the History and Applications of Mathematics at Imperial College London, provided a fascinating assessment of the nature of time in a series of BBC radio talks in 1969, which were later published in an expanded version in his 1972 book What is Time?  In this wide-ranging analysis, he examined our conscious awareness of time and the various biological “clocks” in our bodies which give us a sense of its passing.  Then there are the processes of precise time measurement, and our memories of the past, which dictate our image of the world around us.

But concepts of relativistic time and relational time throw all that out in terms of being the basis for any absolute assessment of reality.  At the end of the day, clock time is an illusion.

In Finding the flow (New Scientist, 21 April 2018), Michael Brooks focuses on the fact that the steady uniform passage of time that we perceive is not real: “You’re living in a moment that science says does not exist.”  Nowadays, we tend to base our understanding of time’s flow on the second law of thermodynamics – entropy in the universe is always increasing, so the direction is clear.  But that may not be so – this may be just a local phenomenon that does not apply to the universe as a whole.

Referring to the work of theoretical physicist Carlo Rovelli of Aix-Marseille University in France and his 2017 book The Order of Time, Dr Brooks leads us to question whether quantum theory suggests that there is actually no order of time in the quantum world.  Heisenberg’s uncertainty principle dictates that it doesn’t exist until measurement turns it into something that is observable.  So a “quantum origin of our experience of flowing time” may indicate that our intuition of what time is, and the difference between past and future, are not fundamental to the fabric of reality.

There seems little doubt that “time” is not some easily comprehensible simple package as might be suggested by classical physics.  Could it just be something we perceive that enables us to make sense of the world, raising Dr Rovelli’s question – do we exist in time, or does time exist in us?  Or as Professor Whitrow expressed it in his 1972 book, it may be that “time is a fundamental property of the relationship between the universe and the observer which cannot be reduced to anything else.”

If it is really such a flexible concept, the arrow of time might one day be potentially manipulated as in so many time travel stories in science fiction.  The 2012 film Looper shows its malicious use by criminal organisations who send victims thirty years back in time to be killed since it’s far too difficult to dispose of bodies in their own time.  Such instant killing raises none of the usual time paradoxes – that is, until a victim manages to escape in his own past before he’s shot.  Of course, we would hope that the benefits of time travel might be used for far more altruistic and benevolent reasons.

And if it was indeed possible to go back in time to change one key event, the choice might seem straightforward, as in Ben Elton’s 2014 novel Time and Time Again.  Trying to prevent the First World War from ever happening, with the possible consequence that all the totalitarian misery of the twentieth century might have been cut off from the start, could be an attractive prospect.  But the endless variables of paradox are tricky things.  Even then, given the supposition that time is only a sort of mental construct, who could say with any certainty what may, or may not, have happened?

 

Richard Hayes, Assistant Editor (Odyssey)

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