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Tallis in Wonderland

Time, Tense & Physics

Raymond Tallis on the ‘Theory of Everything But…’

Readers of this column may recall an earlier piece, ‘A Smile at Waterloo Station: The True Mystery of Memory’ in Issue 78, in which I challenged the claim that there is, or ever could be, a purely neurological, that is to say a materialist, explanation of human memory. I focused on those memories in which we explicitly locate things in the past, in particular our own past. Such memories are tensed: indeed, they are crucial to our sense of tensed time. Now, according to Einstein and many other physicists, tensed time is unreal, and tenses are illusions, although rather ‘stubborn’ ones, as Einstein admitted. Since matter does not entertain illusions, there cannot be a materialist account of memory.

You may be relieved that I am not planning to take yet another pop at physicalist accounts of consciousness. My target this time is somewhat bigger: it is physics itself. Or to be more precise – since I am not so ungrateful as to criticise a science responsible for most of the technology that has made my life longer, healthier, more comfortable and more fun than that of pre-scientific man – I want to take issue with those who believe physics has the last word on the nature of time, or indeed ourselves. I think physics captures very little of what matters to us about time. Consequently, its much vaunted aspiration to develop a ‘Theory of Everything’ – which ‘everything’ presumably includes time-torn beings like you and me – is absurd.

The shortest of the many arguments for saying that tensed time isn’t real goes like this. The observed time relations between events will depend upon the viewpoint (more accurately the inertial frame of reference) of the observer. Consider two events A and B. One observer will see that A precedes B, another will see them in reverse order, and a third may judge them as being simultaneous. All three are equally valid. It follows that A is not intrinsically ‘past’ , ‘present’ or ‘future’ relative to B. These realms, therefore, do not exist in the physical world. What does exist? According to the ‘block universe’ account, it is the spacetime continuum in which the entire history of the cosmos is taken together.

The belief that tensed time is ontologically second-rate has many advocates, including some philosophers of the greatest distinction. D.H. Mellor’s engrossing Real Time (1985) argues that ‘real’ time is tenseless. Suppose I say, “Event A is in the past.” Mellor argues I am not really locating the event in a mysterious realm called ‘The Past’: I am merely saying Event A happened before another Event B, the present utterance – the very speech act which states that Event A happened in the past. So there is nothing mysterious about ‘The Past’; it is simply ‘earlier-than-now’ – and ‘now’ boils down to the time of the utterance. Other utterances at different times would ascribe another tense to Event A. Event A’s apparent tense is therefore entirely down to its temporal relation to the utterance speaking of it. Physical events do not undergo a strange pilgrimage from The Future to The Present, and thence to The Past.

Einstein and Mellor share a contradictory tendency both to centralise and to marginalise the observer. Yes, Einstein seems to place the observer at the centre of things, by arguing that her frame of reference fixes the observed physical order of events for her, and there is no order outside of observation. For Mellor, the observer, that is, the individual uttering the sentence which assigns Event A to The Past, also seems to be central. But in both cases this affirmative action for the observer is cancelled out by reducing her to something less than a human being.

Changing Times

Consider Mellor first. For him, the utterance (Event B) defines what is ‘now’, and allocates a tense to Event A. What Mellor overlooks is that Event B can do this only because of the speaker’s conscious awareness of being in the present, which divides time into past and future. It is the speaker, not the emitted sentence, that establishes the now; and while now has no physical reality, it is nonetheless real: ‘now’ marks an undeniable boundary between events that are recollected and those that are anticipated. Just because it is a conscious individual who creates ‘now’, not a physical Event B which tags a particular time, doesn’t make now unreal. However, if we restrict our attention to the objective relation between Event A and Event B and deny the importance of the person who manufactured Event B, and for whom B was ‘now’, we will indeed fail to find tensed time – and thus arrive at the erroneous conclusion that tenses are unreal. However, what we should rather conclude is that physical events are not enough to establish tensed time.

Although Einstein is ineradicably associated with (apparently) bringing the observer into the heart of the physics of time, motion and gravity, he too erased the conscious subject. Yes, he demonstrated that there is no absolute (that is to say, observer-independent) time or space within which events have an intrinsic, entirely objective location. However, Einstein’s observer was not a living flesh-and-blood individual, or even a physicist. She was reduced to something defined by a set of variables, such as the three of space and the one of time. It turns out that Einstein’s now-less no-one is just a group of numbers which specify an observation-post which does not have to be occupied – the location of a nominal consciousness that is not conscious at all. ‘Observer’ is a merely honorary title. (Physics, ultimately, is about numbers. It’s the representation of reality as co-variant variables with numerical values.)

The View From Everywhere

The elimination of tense yields an image of reality as a tenseless spacetime continuum in which the entirety of the history of everything is taken together. This is clearly problematic – but not for the reason people sometimes think. The space-time manifold isn’t a frozenunchanging block which fails to reflect our changing world. As JJC Smart pointed out, the sum total of everything, changing and non-changing, must itself be unchanging: we cannot supplement a total with more changes. But this is a matter of definition, not a characterisation of anything’s state. The reason why identifying reality with the tenseless spacetime continuum is wrong is that the world being summed to a total presupposes a synoptic, indeed a panoptic, eternal gaze. This could only be a mathematical construct, not a genuine viewpoint, as it would require an observer of a kind that relativity forbids. All actual viewpoints have to be located at a particular point inside the continuum, not outside it (as would be necessary to observe all of it), but a view from inside relativises the continuum. What’s more, a viewpoint outside the manifold would be an addition to the totality – a contradiction in terms.

So what Einstein offers us as reality is the sum total of things viewed from no viewpoint – an idea that is even more thoroughly self-cancelling than Thomas Nagel’s famous ‘view from nowhere’. We arrived at Einstein’s idea of an (actually unsustainable) viewpoint through taking too seriously a mathematics which generates virtual viewpoints that seem like places you might inhabit. You can do maths about uninhabitable viewpoints to great effect – as Einstein did as a teenager, when he envisaged himself travelling at the speed of light and tried to imagine what he would see. The fact that the Einsteinian observer can occupy places that could never be occupied by a real conscious being is no accident: numbers do not require board and lodging, or indeed, display any human characteristics. But we must not be misled into thinking of these theoretical positions as viewpoints ordinarily construed, from which someone could view something.

And thus the very thinking that highlighted the observer’s viewpoint ironically resulted in squeezing out the living, conscious individual. Once viewpoints are reduced to mathematically-defined positions, they are effectively eliminated from reality. So it is hardly surprising that the most important aspect of time, tenses, which mark the difference between the irreplaceable here-and-now and memory and anticipation, regret and hope, ambition for the future and grief at loss, also disappear from view or are deemed unreal. This is fine when we are dealing with matter, but not when we are thinking about conscious individuals such as us who are more than bits of the material world.

Einstein was sometimes uncomfortable with rejecting tensed time. In About Time (1996), Paul Davies quotes Einstein’s admission to the philosopher Rudolf Carnap that the problem of the ‘now’ worried him seriously, and that it might, after all, lie “just outside the realm of science.” You bet, Albert! At any rate, the unsatisfactory consequences of trying to treat time as if it were physical, and the reality revealed to physics as if it were the only aspect of reality, are exposed when the observer is restored to her reality as an aware individual with tense-sensitive concerns. Since absolute Newtonian time evaporates in the relativising gaze of Einstein’s theory, we might even be justified in concluding that tensed time, far from being ‘a stubborn illusion’, is time at its most real.

Everything But The Theorist

Denying the reality of tensed time illustrates what happens when physics exceeds its proper bounds. Shrinking the conscious subject to an observer who is in turn reduced to a group of values assigned to mathematical variables, thus discarding memory and anticipation keyed to a ‘now’ (in turn rooted in ‘me’, ‘here’), empties time of what matters to us. Psychological reality is no less real for not being reducible to physical reality.

A purely physics-based Theory of Everything will at best be a ‘Theory of Everything But the Theorist’ – and that is a mighty big omission. Even the rediscovery of something like a Newtonian absolute ‘now’ agreed throughout the universe would not supply what is needed. A Newtonian absolute, ubiquitous now would be ownerless – unlike the existential now, which is maintained not by observers reduced to mathematical points, but by breathing, thinking individuals who look forward in hope and look back in anger. Everyday ‘I-time’, with its profound distinction between past and future, is not ready to be consigned to the ashcan of thought.

One would have to be arrogant, ignorant, stupid or ungrateful not to be struck with wonder at the power of physics to grasp physical reality. But the human world eludes its grasp. The mysteries of memory and of tensed time remind us of that. “Time,” Bernard d’Espagnat observed, “is at the heart of all that is important to human beings.” To reduce time to tenseless physical time is to lose what lies at the heart of that heart.

Raymond Tallis is a physician, philosopher, poet and novelist. His latest book Michelangelo’s Finger: An Exploration of Everyday Transcendence is published by Atlantic.