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| Carlo Rovelli points out that our entire conception of reality is blurred, necessarily – we can only discern the big events, not the infinitesimally small. Photo: Stefania D’Alessandro/Getty Images |
We live in the past. When we look
deep into the night sky the radiance of the stars we see is anything
from minutes to millions of years old: we are stargazing into the past.
Even here on earth the “present moment” is an illusion. The light that
for me is the image of your face takes an interval of time, however
brief, to reach the retina of my eye, so that for me the you I see is
you as you were an instant ago. It is a dizzying thought. Carlo Rovelli
has many such facts and phenomena to confront us with, that require us
to bethink ourselves. As he remarks, “We know little of the actual
relation between what we see of the world and the world itself.”
Rovelli is a physicist working in
the field of quantum gravity – “There is not yet a theory of quantum
gravity that has been generally accepted by the scientific community, or
obtained experimental support” – and is based in Marseilles, where he
directs a research group at the Centre de physique théorique. He is also
a masterly interpreter to the layman of highly complex and
counter-intuitive current theories of the actual nature of reality, that
reality to which most of us outside the laboratory are purblind. As the
title of Rovelli’s previous book has it, Reality Is Not What It Seems.
But have no fear: he is a wonderfully humane, gentle and witty guide
through the theoretical thickets, for he is as much philosopher and poet
as he is a scientist.
Perhaps the easiest means of
access to this captivating, fascinating, profoundly beautiful but
undeniably intricate book is to consider, as Rovelli does in Chapter 4,
the contrast between Aristotle’s and Isaac Newton’s notions of what time
is. For Aristotle, philosopher of the actual, time is nothing more or
less than the measurement of change: “If nothing changes, there is no
time.” Newton, on the other hand, founded his physics on the premise
that there is such a thing as absolute time – and absolute space, too,
but that is another matter – which passes in a seemingly Platonic
somewhere, “independently of things and of their changes”.
Another structure
We live in a Newtonian universe,
as we must. Newton, it might be said, made a home for us, accommodating,
dependable, built to our scale, and there we reside, and always shall.
There is, however, not next door but on the very same site as our House
of the World, another structure, wherein other laws hold sway, and
another reality is in place. Here the medium in which things exist is
Einstein’s spacetime. “This is the synthesis that Einstein found between
Aristotle’s conception of time and Newton’s,” Rovelli tells us. “With a
tremendous beat of his wing, Einstein understands that Aristotle and
Newton are both right.” However, Newton is mistaken in holding that time
is absolute and independent of things, “that it passes regularly,
imperturbably, separately, from everything else”.
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Source: Irish Times
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| The Order of Time |
Source: Irish Times
