Life is Simple: How Occam’s Razor Set Science Free and Unlocked the Universe
by Johnjoe McFadden (Basic Books, 2021)
This is the history of an idea that was once revolutionary and that continues to shape the modern world. It has become so ingrained in our thinking that scientists use it without acknowledgement, and it is so prevalent that “Occam’s Razor” is embedded in the English language. Isn’t it a mystery though that politics and popular thinking seem sometimes to have abandoned clarity and the simplest explanations for tangled conspiracy theories and other Magical Thinking. Occam’s Razor is a tool at the cutting edge of all successful scientific accounts of the world. Einstein put it well in describing physics as the search for the neatest (or simplest) theory of everything.
In places the author of Life is Simple overstates his case, claiming that Occam’s Razor has influence well beyond the selection of rival scientific explanations. In the introduction he says that it has influenced wider culture, with examples in 20th century Modernity such as the music of John Cage, the architecture of Corbusier and the plays of Beckett. Really? The design of the iPad and the KISS principle (Keep It Simple, Stupid!) in engineering, perhaps? Here I question his clarity of thinking: the style of modernist writers and artists stems from an aesthetic, not philosophical, rejection of previous ideas; an artistic fork in the road that might just so easily blossom again into some New Baroque of over-complicated decoration. The iPad and engineering design concepts have been shaped by ergonomics, unless that whole discipline is itself an embodiment of Occam’s idea? And artistic movements may have causes and influences, but do not require explanatory power. So, my first impressions were that McFadden is over-generalising. Not every simplification is justified.
That said, Johnjoe McFadden writes a very readable and, in places, dramatic story. It begins with “Scholars and Heretics” with dangerous ideas that rock the ecclesiastical boat. A Papal summons, monks smuggled out of a city for fear of their lives, the risk of betrayal and death at the hands of an all-powerful Church was very real in medieval Europe. Just for thinking differently. There is a fine explanation of the background in ancient cosmologies (Plato’s Idealism, the crystal spheres) culminated in Ptolomy’s masterpiece of “circles, epicycles, eccentrics and equants” which worked tolerably well to describe the heavens.
How can a model that is so wrong get so much right?
In my humble opinion, Augustine was a disaster for the Church and for Western Philosophy, as well as being an intolerable hypocrite. (I’ll save that for another time though!) What is certain is that for this story he brings in a wave of anti-intellectualism such that the survival and development of classical knowledge relied on the work of Islamic scholars, whose words were available to the West again only after the brutality of the Crusades and La Reconquista. Then it fell to the “dumb ox” Thomas Aquinas with use of Aristotles “four causes” which led to the five proofs for the existence of God, so beloved of the Scholastics. Aristotle’s theories of Universals in ten Categories together with syllogistic logic were the system of thought that ruled for a long time and provided an “explanation” of the Eucharist.
Enter William of Occam. He challenged the unrestricted complexity of this system of thinking, and in several forms expressed that “it is vain to do with more what can be done with less”. In this context we can now understand how undermining Aristotle’s foundations was so dangerous. Aquinas had described Theology as “The Queen of Sciences”; Occam dismissed it as not a science at all! He disproved all five of the proofs of God’s existence and by rejecting Aristotle’s Universals pulled philosophical rug from under the Catholic Church’s version of the Eucharist. Heresy!
Life is Simple takes us from the life of Occam into the influence of his Big Idea. The meat of the book is a crystal-clear history of science, with sections on physics (how do planets behave? is everything made of atoms? what are the laws of motion), biology (is there a life force? how do plants animals and people inherit characteristics from their parents?), and the baffling world of quantum mechanics. Each episode brings in the lives of those involved with making great discoveries – McFadden puts the human stories in good context, such as Kepler’s dodgy acquisition of the late Tycho Brahe’s data, or the mathematical genius of Emmy Noether, of whom I would like to find out more. I would say this is one of the most readable, accessible and enjoyable short histories of science that I have come across, held together by this thread of influence of Occam’s Razor, cutting through the maze of observations to the simplest explanation over and again. Possibly because it was so good, I was stimulated into taking issue with the way he sometimes did this, which didn’t always work for me.
Chapter 15, for example, on the science of heredity, stood out as a very clear account of Gregor Mendel’s work and his systematic experimental methods are a good example of how the principle of simplicity is applied.
[…] Mendel did not need to quote […] Occam to justify his preference for simplicity. It had become so much second nature that most scientists were unaware that they were working that way.
McFadden (from Chapter 15)
But what is described here is the careful control of variables that is essential to good scientific method. I see a distinction here between the legacy of Francis Bacon’s inductive reasoning (applied to experimentation) and of Occam (applied to selection between rival models). One is practical, the other theoretical. The former may be a necessary precondition for the latter. McFadden doesn’t however seem to attribute Bacon’s thinking to knowledge of Occam, though the use of indictive argument paralleled Occam’s work from 300 years previous.
The same chapter ends with a section on the “Use it or Lose it” principle whereby genes that encode functions that are no longer crucial to an animal thriving (e. g. eyesight in naked mole rats) are subject to mutation and “pseudogenisation” because there is now no environmental pressure to select for the redundant (or vestigial) characteristic. But this biological process, as inevitable as it is, does not really constitute “a kind of evolutionary Occam’s razor” as McFadden claims. It is more akin to an increase in entropy, a slide towards chaos and disorder (if there is nothing to maintain a pattern). And DNA is not exactly “simplified” by the loss of function of some genes. And doesn’t a certain amount of redundancy in encoding allow for robustness if the environment changes?
But this feels a little like criticising the cutlery after a wonderful meal. McFadden has written a brilliant and well-illustrated book: I recommend it wholeheartedly. It made me stop and think, to re-read and to re-evaluate my own understanding on several topics. This for me is a dream of a book: the history and influence of a Great Idea, brilliantly conceived and very well told.
Elsewhere on the Bookshelf
- So what do you know? – Welcome (grandpops-bookshelf.co.uk)
- Morsels of the Night Sky – Welcome (grandpops-bookshelf.co.uk)
- Stephen Pinker, Rationality: What it is – Why it seems scarce – Why it matters (Allen Lane / Penguin, 2021) this is a thought-provoking book about clear (and unclear) thinking. It matters.
- Daniel C Dennett, Darwin’s Dangerous Idea: Evolution and the Meanings of Life (Penguin, 1995)
- Peter Watson, Ideas: A History from Fire to Freud (Weidenfeld and Nicolson, 2005)
- John Gribbin, Science: A History 1543-2001 (BCA / Allen Lane / Penguin Press, 2002)
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