Raymond Tallis wonders how stability has changed.

　　What is really real? In addressing this time-honoured (or, pessimists fear, eternity-honoured) question, philosophers have looked increasingly to science for answers. The result has not always been very satisfactory, as I have often complained in this column. We are invited, cajoled, or bullied into believing that fundamental reality is remote from anything we can experience, intuit, or even imagine.

　　Philosophers of course are not entirely innocent in this regard: they have often proposed unimaginable ways of conceiving the world; and, unlike physicists, they have not rewarded us with technologies that have transformed our lives. The greatest of the Pre-Socratic philosophers, Parmenides, denied the reality of change. His universe was an immobile, unitary, timeless, sphere. Heraclitus adopted the entirely opposite view: everything was change.

　　Thanks to his lucky posthumous break of having Plato (largely) on his side, Parmenides’ views have had huge influence. For Plato also, reality consisted of unchanging items – Forms or Ideas as universals corresponding to types of things or concepts. Individual tables came and went, but the Form of The Table was eternal. The visible and tangible tables, accessed by our senses rather than by our immortal souls and their thoughts, were unreal ‘pale copies’ of The Table. For Plato, real items had three characteristics: they were picked out by thought rather than experienced through the senses; they were abstract; and they were stable or unchanging.

　　Although Parmenides would have disapproved of the multiplicity and variety of unchanging Items envisaged by Plato, he certainly would have approved of the clear connection between reality and stability. And for both thinkers, the real was accessible to reason because reality itself was rational. In seeking reality we must therefore follow reason and ignore the testimony of our senses. Mathematics is the most transparently reason-driven mode of thought, and so we must follow the mathematics where it takes us. Hence the (possibly apocryphal) sign over the entrance to Plato’s Academy: ‘Let no-one ignorant of geometry enter here’.

　　Stabilising Influences

　　Skip ahead two thousand years and we arrive at the Seventeenth Century rationalists – such as Descartes and Spinoza – for whom substances were eternal. This concept had a key influence on the science of the succeeding centuries, most importantly on the growing conviction that there was stability beneath the appearance of change. Indestructible atoms, equations recording chemical reactions and patterns of physical activity in which the left and right side were connected by equal signs (nothing truly lost or gained), and conservation principles of increasing generality – the discovery that momentum, mass and energy are preserved – proclaimed that surface alteration concealed deep stability.

　　As natural science became more mathematized, and the mathematics evolved from dealing with magnitudes to observing patterns, and even patterns of patterns of systems of magnitudes, laws of widening applicability implied that, at the most fundamental level, there is no net change between the beginning and the end of processes. Einstein’s monumental General Theory of Relativity, the culmination of classical physics, re-cast the science of motion – the very essence of change – in such a way that its fundamental laws were preserved irrespective of viewpoint. Upholding this principle of perspective-independent laws led to a picture of the universe as an unchanging Parmenidean Block in which ‘becoming’ was not possible. As Karl Popper reports in The Open Universe (1982), Einstein gladly accepted from him the title of ‘the Parmenidean’.

　　Another influence on the connection between stability and reality should not be ignored: that of religion, in particular the Judeo-Christian tradition, according to which that which is truly real is an unchanging, hidden deity, manifest only intermittently through (in this atheist’s view) injudicious interventions in His Creation. God, however, deserves a bit more attention that I can offer Him in this article, so I will say no more about Him or the metaphysical doctrines of believers. Instead, I want to focus on the everyday roots of the idea that changelessness is the mark of reality, and argue that the counter-intuitive ideas of Parmenides and of General Relativity ultimately tap into ordinary intuitions.

　　Remaining Objective

　　J.L. Austin pointed out in Sense and Sensibilia (1962) that the meaning of ‘real’ tends to be defined in opposition to ‘unreal’, and it is to the latter that we should look when we try to make sense of our feeling that an entity is really real only if it is stable. The paradigm case of unreality is a sensory experience to which nothing corresponds; for example, a visual hallucination. Its existence is fleeting or intermittent, and even if it does persist, what is promised to sight is not delivered to touch or the other senses. It cannot be walked around, either: there is nothing constant that can be accessed from different perspectives. Nor can the hallucination be shared with or by others. It exists, in short, only in brief relation to the perspective of the single sense of a single individual. A real object, by contrast, has a core that is conserved across a multiplicity of senses for an indefinite number of observers and times. The object’s being truly ‘out there’ is evidenced by its being available to be visited and revisited, to be explored and re-explored, by any number of people.

　　We can gather these features under the general characteristic of ‘stability’. The primordial link between stability and reality is therefore reflected in the complex notion of ‘objective reality’. Real objects have something constant about them over time: endurance or sameness through changes of sense organ, perspective, and person. From this it seems to follow that the more real something is, the more it is enduring and unchanging. The intrinsic reality of the object-in-itself is an identity that transcends the fluctuations of, or the succession of, the experiences of it. Immediate, unchecked, sense experience – notwithstanding that it is the final tribunal of what counts as real in everyday life – is stigmatised as cognitively inferior, and its contents not always true to reality.

　　This ultra-lite form of the Parmenidean intuition that reality is composed of unchanging objects rather than fickle sense experiences gives us one aspect of scientific reality. The other aspect is that the objects are best described mathematically – a view whose ultimate expression is the field equations of General Relativity.

　　Measured Responses

　　To understand how we came to see mathematics, and timeless mathematical structures, as the gold standard for what is real, we need to look to the special authority of measurement – first in everyday life, and then in science at an increasingly fundamental level.

　　A key characteristic of measurement that is connected with the claim that it is closer to reality than sense experience, is that it is repeatable. If our measurements are correct, then you, I, or anyone else, should arrive at the same result. This confirmability of measurement reflects how stability is seen as the mark of that which is real in the object. The more times I, and the more observers, get the same result for a measurement, the more it seems to be true of the intrinsic reality of what is being measured.

　　Measurement of course involves sense experience, but in many ways it distances the latter from its own nature and from the sensations of the individual making the measurement. Firstly, a measurement is a discrete act that is not dissolved in the sensory field. It is a kind of interruption in the informal flux of sensation, exposing part of experience to formal scrutiny. Secondly, it attempts to overcome the viewpoint-dependency that is inseparable from ordinary sense experience. The table looks small when it is far way away and larger when it is near, but in the purely quantitative gaze of measurement it is neither large nor small. You and I may agree to disagree over whether the table looks large or small, but we cannot agree to disagree over whether it is or is not 2 feet by 2 feet. Thirdly, the outcome of measurement has little to do with the appearance of the table – after all, ‘2 feet by 2 feet’ can apply to any item that happens to be of that size and shape: to a table, a paving stone, or a canvas by Rembrandt. The qualitative difference evident in sense experience is bracketed in measurement. Finally, the appearance of the actual output of measurement – the record of the results – is irrelevant. It can take the form of spoken words, or visible numbers or graphs, and their exact content – accent, volume, size, or colour of the characters or numerals – is irrelevant.

　　Scientific Abstractions

　　The distance between what counts as real and what is experienced widens as science subjects more of the world to measurement (with an accuracy that lies beyond sense experience), using increasingly indirect methods, drawing on lengthening chains of intermediate concepts (including units, forces and particles), and employing ever more complex instrumentation, itself calibrated by increasingly ingenious means. Its superior – more robust and more generalizable – truths are progressively more remote from the flux of experience as well as from the idiosyncrasies of perspective. The key characteristic, however, remains: repeatability. Confirmation implies stability implies reality. Stability is thus extrapolated beyond the relative durability of the material objects we ordinarily regard as real. Measurements made on what are deemed to be representative samples of a whole category of objects, open the way to quantitative laws that express a sameness beneath sensed difference, and consequently a constancy beneath change. Hence we eventually arrive at the equations and conservation laws that proclaim things to be the same before and after apparent change.

　　The extraordinary power of quantitative natural science makes it impossible to resist conflating the scientific image of the world – compounded out of general laws and a dephenomenalised nexus of stable, timeless mathematically-envisaged structures – with reality itself. Consciousness, individual viewpoints, living subjects, and the changes they observe through the flux of moment-to-moment experience, are an embarrassment to a world picture that has developed through transcending them. Even quite sophisticated thinkers conflate the world picture resulting from the immensely fruitful methodological choices of science with a comprehensive account of what is really out there, and falsely conclude that change itself is unreal if according to the most general laws of physics ultimate reality is unchanging.

　　Plus ?a Change

　　Change is undoubtedly real. Our days, lives, and worlds have unfolding histories. And so, by the way, do philosophy – and science. After the Parmenidean climax of General Relativity, is it time for a scientific Heraclitus to have his day? Quantum mechanics, which Einstein found difficult to accommodate, has questioned the very notion of a definite, self-subsistent reality independent of the flux of experience in the form of measurement. Unfortunately, many quantum physicists are still attached to the idea of stability: the quantum field looks like a frozen mathematical structure. Better instead acknowledge that Parmenides and Heraclitus each captured half of the truth. Change is real, and so is stability. Indeed, there is no change except against a background of stability. While what happens in time may be captured by timeless laws that freeze happening, there is a hidden ebullience even in pebbles.

　　@ Prof. Raymond Tallis 2015

　　Raymond Tallis’s latest book is The Black Mirror: Fragments of an Obituary for Life (Atlantic). His website is raymondtallis.com.

　　（来源：philosophynow.org）