Theoretical physics, practical ethics

It would be fair to say Sean Carroll’s The Big Picture: On the Origins of Life, Meaning and the Universe Itself is an ambitious work.

Carroll is a theoretical physicist who writes elegantly with clarity and good humour about big questions we probably associate more with philosophy than with physics.

As a physicist Carroll subscribes to naturalism, the view that:

“…there is only one world, the natural world, exhibiting the patterns we call the ‘laws of nature’, and which is discoverable by the methods of science and empirical investigation. There is no separate realm of the supernatural, spiritual, or divine; nor is there any cosmic teleology or transcendent purpose inherent in the nature of the universe or in human life.”

Yet Carroll coins the term ‘poetic naturalism’ to describe his own approach. The word poeticreminds us that there is more than one way of talking about the world.’

The Big Picture is not without its own wry humour, mostly by way of parenthetical remark. ‘(As of this writing, Mars is the only planet to be inhabited solely by robots.)’.  I often found myself thinking of lines from Douglas Adams or Gary Larson cartoons that might have complemented the text.

Carroll takes us through a potted history of the naturalist view from Galileo and Ibn Sina to Laplace, Descartes and Thomas Bayes. Bayesian reasoning becomes a major theme throughout the book. The more recent the scientific history gets, the harder the ideas become to grasp. The details of quantum mechanics, alas, escape me but Carroll is a gentle and friendly guide and his main argument is always much broader than the scientific detail.

Emergence is another important theme. In an illuminating passage Carroll writes about Van Gogh’s The Starry Night. The canvas and paint are just atoms in particular locations.

“Van Gogh didn’t infuse it with any form of spiritual energy; he put the paint onto the canvas.” … “But it’s obvious that specifying an arrangement of atoms isn’t the only way of talking about this physical artefact, and it’s not even the best way for most purposes.”

As Carroll points out, the mood the painting evokes, the effect of the colour palette and the swirling sky are ‘emergent properties’.

Carroll gives us a more detailed example of emergence in the discussion of two ways of thinking about the air in the room. Air is a gas which we can think of, usefully, as a continuous fluid, but at the microscopic level air is composed of atoms and molecules. Specifying the state of each molecule at each point in time is one description; describing its macroscopic properties as a fluid is another. Yet both are accurate and describe ‘the same underlying reality’. Carroll’s discussion of these two ways of talking – both valid, useful and mutually consistent – is wonderfully clear, science writing.

The early parts of the book take us through what we know of the universe and how we know it. In his discussion of ontologies Carroll gives due weight to reason and the scientific method as we might expect but he is never dogmatic.

“By its nature, science needs to be completely open to the operation of the world, and that means that we stand ready to discard any idea that is no longer useful, no matter how cherished and central it may once have seemed.”

This reminded me, of Darwin in his Autobiography:

“I have steadily endeavoured to keep my mind free so as to give up any hypothesis, however much beloved…as soon as facts are shown to be opposed to it.”

In one sense though, all this history of ontologies is but throat clearing before getting to what Carroll really wants to address. It amounts to the challenge of mapping our understanding of the nature of the universe to the very different daily lived experience of being in it.

“Can we make sense of consciousness and our inner experience without appealing to substances or properties beyond the purely physical? Can we bring meaning and morality to our lives, and speak sensibly about what is right or wrong?”

Carroll runs through contemporary theories of evolution by natural selection and the origin of life and how this work helps us understand how complexity emerges. We get a tour of neuroscience and modern philosophy through the work of Alan Turing, John Searle and Daniel Dennett. I kept recalling the Larson cartoon in which one amoeba berates another – “Stimulus response! Stimulus response! Don’t you ever think?”

The final section of the book is titled ‘Caring’ and is more personal. Building on the many ideas of those others he has read and absorbed, Carroll presents us with his own conclusions. He ends with a recollection of his late grandmother which is both perfectly ordinary and very moving.

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