Seven Brief Lessons on Physics
A review of Seven Brief lessons on Physics by Rob Mason
Seven Brief Lessons on Physics by Carlo Rovelli
When we talk about the Big Bang or the fabric of space, what we are doing is not a continuation of the free and fantastic stories which humans have told nightly around campfires for hundreds of thousands of years. It is the continuation of something else; of the gaze of those same men in the first light of day looking at tracks left by antelope in the dust of the savannah – scrutinizing and deducting from the details of reality in order to pursue something which we can’t see directly but can follow the traces of. In the awareness that we can always be wrong, and therefore ready at any moment to change direction if a new track appears: but knowing also that if we are good enough we will get it right and will find what we are seeking. This the nature of science.
The confusion between these two diverse human activities – inventing stories and following traces in order to find something – is the origin of the incomprehension and distrust of science shown by a significant part of our contemporary culture. The separation is a subtle one: the antelope hunted at dawn is not so far removed from the antelope deity in the night’s storytelling.
The border is porous. Myths nourish science, and science nourishes myth. But the value of knowledge remains. If we find the antelope we can eat.
Our knowledge consequently reflects the world, It does this more or less well, but it reflects the world we inhabit. This communication between ourselves and the world is not what distinguishes us from the rest of nature. All things are continually interacting with each other, and in doing so each bears the traces of that with which it has interacted; and in this sense all things continuously exchange information about each other.
The information which one physical system has about another has nothing mental or subjective about it; it’s only the connection that physics determines between the state of something and the state of something else. A raindrop contains information on the presence of a cloud in the sky; a ray of light contains information on the colour of the substance from which it came; a clock has information on the time of day; the wind carries information about an approaching storm; a cold virus has information of the vulnerability of my nose; the DNA in our cells contains all the information in our genetic code (on what makes me resemble my parents); and my brain teems with information accumulated from my experience. The primal substance of our thoughts is an extremely rich gathering of information that’s accumulated, exchanged and continually elaborated.
How can the continuous exchange of information in nature produce us, and our thoughts?
There is one issue in particularly regarding ourselves which often leaves us perplexed: what does it mean, our being free to make decisions, if our behaviour does nothing but follow the predetermined laws of nature? Is there not perhaps a contradiction between our feeling of freedom and the rigour, as we now understand it, with the way things operate in the world? Is there perhaps something in us which escapes the regularity of nature, and allows us to twist and deviate from it through the power of our freedom to think?
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.
The solution to the confusion lies elsewhere. When we say that we are free, and it’s true that we can be, this means that how we behave is determined by what happens within us, within the brain, and not by external factors. To be free doesn’t mean that our behaviour is not determined by the laws of nature It means that it is determined by the laws of nature acting in our brains.
Our free decisions are freely determined by the results of the rich and fleeting interactions between the billion neurons in our brain: they are free to the extent that the interaction of these neurons allows and determines. Does this mean that when I make a decision it’s ‘I’ who decides? Yes, of course, because it would be absurd to ask whether ‘I’ can do something different from what the whole complex of my neurons has decided: the two things, as the Dutch philosopher Baruch Spinozo understood with marvellous lucidity in the seventeen century, are the same.
There is not an ‘I’ and ‘the neurons in my brain.’ They are the same thing. An individual is a process: complex, tightly integrated.
When we say that human behaviour is unpredictable, we are right, because it is too complex to be predicted, especially by ourselves. Our intense sensation of internal liberty, Spinoza accurately saw, comes from the fact that the ideas and images which we have of ourselves are much cruder and sketchier than the detailed complexity of what is happening within us. We are the source of amazement in our own eyes.
We have a hundred billion neurons in our brains, as many as there are stars in the 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.
The ‘I’ who decides is the same ‘I’ which is formed (in a way that is still certainly not completely clear, but which we have begun to glimpse) from reflections upon itself; through self-representations in the world; from understanding itself as a variable point of view placed in the context of the world. From that impressive structure that processes information and constructs representations which is our brain. When we have the feeling that ‘it is I’ who decides we couldn’t be more correct. Who else?
I am, as Spinoza maintained, my body and what happens in my brain and heart, with their immense and, for me, inextricable complexity.
The scientific picture of the world which I have related in these pages is not then, at odds with our sense of our selves. It is not at odds with our thinking in moral and psychological terms, or with our emotions and feelings.