Carlo Rovelli: ‘Reality Is Not What It Seems’ (Penguin, 2017)

Professor Rovelli is a notable physicist.

The book represents leaps across the history of science – and quantum leaps too.

This book is well written but dense, especially as it progresses.  Relevant mathematical equations are quoted but remain impenetrable to most readers.  (This is a book for the general reader.)

Note that critics with background knowledge take issue with some of his statements and claims.

As indicated, Professor Rovelli “leaps” from the science and philosophy of Ancient Greece.  He takes the opportunity to praise the thinking of Democritus, the first writer reported to have put forward an atomic theory.

Moving on to the Romans, Rovelli singles out for praise the poet and philosopher Lucretius and his long poem – De Rerum Naturâ, On The Nature of the Universe:

Lucretius sings of atoms, the sea, the sky, of nature.  He expresses in luminous verse philosophical questions, scientific ideas, refined arguments.  [Page 20]

This is an example of the writer combining mathematical and scientific argument with with enthusiastic references to poetry.

Professor Rovelli builds on the work of a succession of great mathematicians and physicists (too numerous to mention here), in order to discuss ways of reconciling two great theories – relativity and quantum mechanics.  At the same time, he contemplates a finite rather than an infinite concept of the universe.  One of the models he delineates is that of the “3-sphere” (a technical concept).

Professor Rovelli writes:

Einstein’s idea is that space could be a 3-sphere: something with a finite volume (….) but without borders. The 3-sphere is the solution which Einstein proposes in his work of 1917 to the problem of the border of the border of the universe.  This article initiates modern cosmology….From it will arise the discovery of the expansion of the universe; the theory of the Big Bang; the problem of the birth of the universe, and much else besides.  [Pages 79f]

Professor Rovelli goes on to turn to the “classic” poet of his native Italy, namely Dante Alighieri, making a link between his Paradiso (Cantos XXVII and XXVIII) and the 3-sphere concept.  (He is not the first to suggest this.)  In brief, the more or less Ptolemaic concept of the universe adopted by Dante (but modified) has (i) the solar system embracing God and the celestial choir and (ii) vice versa!

Professor Rovelli states:

[Dante] ascends [the celestial] spheres….up to the outermost sphere.  When he reaches it, he contemplates the universe below him….But then he looks even higher – and what does he see?  He sees a point of light surrounded by immense spheres of angels, that is to say, by another immense ball, which, in his words ‘surrounds and is at the same time surrounded by’ the sphere of our universe!….The point of light and the sphere of angels are surrounding the universe, and at the same time they are surrounded by the universe!  It is an exact description of a 3-sphere!

This is intriguing for me and it will spur me to revisit this part of the Commedia.  (More to follow, from me, on this point, perhaps.)

Worth reading.  To be taken with a pinch of salt.  At the “cutting edge” of science, there is room for disagreement among scientists.