Seven Brief Lessons on Physics by Carlo Rovelli
Rating: 9/10
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One Sentence Wrap-Up
Seven brief, accessible lessons covering post-Newtonian physics with the chapter title speaks for itself: 1) The Most Beautiful of Theories (i.e. Einstein's General Relativity); 2) The Quanta; 3) The Architecture of the Cosmos; 4) Particles; 5) Grains of Space (i.e. Loop Quantum Gravity); 6) Probability, Time and the Heat of Black Holes; 7) Ourselves.
Summary Notes
The lessons began as columns in an Italian newspaper within the culture section, hence they are short and to the point, summarising recent scientific theories such that they are understandable to the general readers. I would say that the book is more of an introduction than a deep dive, written in a poetic and elegant manner with the aim to pique the reader's interest. The author does not stray from the 'why', which is the key in inspiring the reader to further explore the scientific theories by themselves (i.e. the how).
Essentially a gateway to Disneyland for a young, aspiring scientist.
I found the concepts to be similar to his other book Reality Is Not What It Seems: it does not bring anything new to the table, but a summary structured in a way that I could revisit the key themes by chapter easily. As such, I would be more inclined to reread this book rather than his other book Reality Is Not What It Seems even though I like his other book more. Don't get me wrong though, both are amazing books that I would have no hesitation in recommending!
Key Lesson Learnt - We are a product of nature; nature is our home, and in nature we are at home
My key takeaways are more or less the same as Reality Is Not What It Seems, with one additional lesson...
I might be overlapping my thinking with another book that I am currently reading (I am looking at you - The Beginning of Infinity)... We often think of ourselves as special, unique and different from everything else in the universe. It is not a surprise given that we seem to be the only species that has the ability to construct hypothesis, criticise / validate findings and refine explanations. Does it mean that we are 'outside' the norms of nature?
The author does not think that is the case.
Well, no, there is nothing about us that can escape the norms of nature. If something in us could infringe the laws of nature we would have discovered it by now. There is nothing in us in violation of the natural behaviour of things. The whole of modern science - from physics to chemistry, and from biology to neuroscience - does nothing but confirm this observation.
To him, we are the complex representation of nature. Nature is not at odds with our sense of ourselves. The fact that we do not understand the whole of our reality is similar to our limited knowledge about ourselves (i.e. how our brain works, how consciousness comes about, etc.).
We have a hundred billion neurons in our brains, as many as there are stars in a galaxy, with an even more astronomical number of links and potential combinations through which they can interact. We are not conscious of all of this. 'We' are the process formed by this entire intricacy, not just by the little of it of which we are conscious.
That which makes us specifically human does not signify our separation from nature; it is part of that self-same nature. It's a form which nature has taken here on our planet, in the infinite play of its combinations, through the reciprocal influencing and exchanging of correlations and information between its parts.
We are a product of nature with nature being our home. The world that we are revealing - in which space is granular, time is a concept rather than reality, etc. is not something that is out of the ordinary: they are the composites of reality. It is just that we are limited by our senses and knowledge to understand nature as it is. We should appreciate having nature as our home; continue to seek to understand it and learn to cherish it such that we could extend our mortality as a civilisation.
I believe that our species will not last long... We belong to a short-lived genus of species. All of our cousins are already extinct. What's more, we do damage. The brutal climate and environmental changes which we have triggered are unlikely to spare us. For the Earth they may turn out to be a small irrelevant blip, but I do not think that we will outlast them unscathed... We are perhaps the only species on Earth to be conscious of the inevitability of our individual mortality. I fear that soon we shall also have to become the only species that will knowingly watch the coming of its own collective demise, or at least the demise of its civilisation.
Favourite Quotes
A handful of types of elementary particles, which vibrate and fluctuate constantly between existence and non-existence and swarm in space even when it seems that there is nothing there, combine together to infinity like the letters of a cosmic alphabet to tell the immense history of galaxies, of the innumerable stars, of sunlight, of mountains, woods and fields of grain, of the smiling faces of the young at parties, and of the night sky studded with stars.
The world described by the theory is thus further distanced from the one with which we are familiar. There is no longer space which 'contains' the world, and there is no longer time 'in which' events occur. There are only elementary processes wherein quanta of space and matter continually interact with each other. The illusion of space and time which continues around us is a blurred vision of this swarming of elementary processes, just as a calm, clear Alpine lake consists in reality of a rapid dance of myriads of minuscule water molecules.
Compare 'now' with 'here'. 'Here' designates the place where a speaker is: for 2 different people 'here' points to 2 different places. Consequently 'here' is a word the meaning of which depends on where it is spoken. The technical term for this kind of utterance is 'indexical'. 'Now' also points to the instant in which the word is uttered, and is also classified as 'indexical'. But no one would dream of saying that things 'here' exist, whereas things which are not 'here' do not exist. So then why do we say that things that are 'now' exist and that everything else doesn't? Is the present something which is objective in the world, that 'flows' and that makes things ' exist' one after the other, or is it only subjective, like 'here'?
Our memory and our consciousness are built on these statistical phenomena. For a hypothetically supersensible being there would be no 'flowing' of time: the universe would be a single block of past, present and future. But due to the limitations of our consciousness we only perceive a blurred version of the world, and live in time.
We are nature, in one of its innumerable and infinitely variable expressions.
