Stephen Weinberg’s (2015) book ‘To Explain the Modern World’ is an interesting attempt to explain how modern science has developed. He begins with pre-Socratic philosopher/scientists like Thales, and Parmenides and works his way through Plato and Aristotle to the Hellenistic age with such figures as Ptolemy and moves on to consider the work of Descartes, Galileo culminating in the work of Newton. At the end of the book he considers post-Newtonian physics briefly but the central aim of the book is to explain how science developed up until the magnificent work of Newton.

There are a lot of good points in the book. One really welcome aspect of the book is semi-technical appendixes which help understand in a bit more detail some of the logic and mathematics behind the various theories he is explaining. These appendixes are easy to follow and help give some much need content that is often sorely missing in other pop-science books. Furthermore he doesn’t present the entire world pre-Copernicus as filled full of raving idiots. Some scientists who don’t bother actually study pre-scientific attempts to understand the world often pretend that all theorists prior to the scientific revolution were pretty much making things up as they went along. Weinberg avoids this trap and manages to illustrate the sometimes sound reasoning that went in to the various pre-scientific cosmologies. That said Weinberg has no difficulties criticising theorists for getting things wrong either on their own terms or according to our present day lights. He explicitly sets himself up against the view attributed to Kuhn (in his more radical phase) where we are not really in a position to judge different scientific paradigms because some paradigms are incommensurate and cannot judged by the same standards.[1] Weinberg is defending the idea of scientific progress and has no problem criticising earlier theorists for either getting things wrong by our lights or on their own terms. Here he is on Aristotle:

“But if Aristotle really did present the scheme presented in ‘The Metaphysics’ , then this cannot be explained as a matter of thinking in terms differently from ours, or being interested in different problems from ours. We would have to conclude that on his own terms, in working on a problem that interested him, he was either careless or stupid” (‘To Explain the World’ p.84)

Weinberg’s irreverence is refreshing he criticises any idea or theory which he finds lacking in evidence.

His discussion of the Hellenistic era is particularly interesting. He argues that despite the typical historical narrative of the world of Plato and Aristotle being the pinnacle of pre-scientific thought in fact the Hellenistic era gave us superior results in science (by which he means pretty much means physics) than anything Plato or Aristotle gave us. The emphasis in the Hellenistic era on practical inventions as opposed to grand speculative narratives Weinberg conjectures lead to them making more progress in physics than their predecessors.

Despite the fact that I enjoyed the book and learned a lot from it there was aspects of it that I was less armoured with. One constant irritation was Weinberg’s focus on nothing but physics (and to a much smaller degree chemistry). This choice was obviously justified by the fact that Weinberg as a Nobel Prize winning Physicist knows the history of physics much better than he knows the history of the development of the other sciences. However when a book has a subtitle ‘The Discovery of Modern Science’ I think the author owes us something more than a history of one branch (albeit the most successful one) of science.

His focus on one area science makes him give some dreadfully one sided caricatures of various philosophers. A case in point is Plato. Anybody who has studied Plato to any degree at all will admit that he wasn’t a physicist in any sense of the word. While some pre-Socratic Philosophers could be considered in a very crude sense proto-physicists, and likewise Aristotle could be considered a crude proto-physicist. Plato on the other hand had no interest in cosmology and when he discusses it he merely offered crude creation myths (For example see the end of The Phaedo). Because of this fact Weinberg dismisses Plato as a poetic thinker who was not really concerned with accurately representing the world but rather was concerned with aesthetic matters.

This is a stunningly unfair characterisation of Plato. Plato discussed many different topics from human nature, to the best form of human society, the nature of mathematics, ethics, etc. Plato’s work on innate ideas was one of the first examples of what later became to be known as a poverty of stimulus argument. Chomskian linguistics used the same logic to argue for an innate grammar over the last fifty years. Chomsky explicitly acknowledges his dept to Plato by naming his poverty of stimulus arguments in linguistics; Plato’s problem. Furthermore Plato’s tripartite theory of the mind prefigured both Hume and Freud. His views on human nature were formed by both empirical observation and logical analysis typically achieved through systematic dialogue. His views should be considered early attempts to do psychology not as some crude poetry unconcerned with discovering the truth.

Plato’s theory of what a just society should be also took account of things like human nature and tried to accommodate what he thought about human nature into how we should build our society. He was spectacularly wrong at times. But his views were very important steps on the way to understanding subjects like sociology, psychology and political science as well. So I think Weinberg was entirely wrong to dismiss Plato as a spinner of myths, and I believe he was only lead to this because of his excessive focus on physics as the only real science.

When he appeared at the recent ‘Moving Naturalism Forward’ conference Weinberg offered his theory of ethics. His crude position amounted to a claim that he doesn’t care what a utilitarian ethics teaches us he and most people are simply going to look after their own and not make the sacrifices that people like Singer recommend. Weinberg didn’t really offer much justification for his views and wasn’t really pressed by the other panellists. Presumably he had some idea that our human nature will prevent us from being strict utilitarians. Perhaps he is right but his claim reminded me of the confident assertions Socrates foils often made in Plato’s dialogues. Socrates often managed to convince his opponents they were incorrect by drawing them into a series of contradictions implicit in their confident claims. I think Plato’s dialogues remind us that our express views on ethics are not always as internally consistent as we think. And that testing our intuitions using various thought experiments gives us a way of weeding out our contradictory beliefs. Plato here helped us on the road to understanding our ethical beliefs better. And this is now a flourishing area of science and philosophy.

I mentioned earlier Plato’s views on innate ideas and how he integrated his views on human nature to his theory of the ideal society. This approach was maintained throughout the history of political philosophy; thus Hobbes and Rousseau’s differing views on human nature influenced their views on the way we need to build a just society. The debate between Descartes and Locke on innate ideas was a follow on from Plato’s arguments. Locke and Descartes appealed to anthropological evidence, historical evidence, psychological evidence and logical arguments in their debate. This debate has been replaying itself throughout history with different protoganists like Skinner and Chomsky arguing for different amounts of innate apparatus. Some of this was detrimental to psychology as it polarised people too much in one direction or another but it is undoubtable that Plato, Locke and Descartes played a huge role in the development of psychology, political science, linguistics etc.

I think that by ignoring the role these philosophers played in developing sciences other than Physics Weinberg did the philosophers a huge disservice. He also did science a huge disservice by again overplaying the importance of physics and chemistry in relation to all of the other sciences like psychology, biology etc.

[1] I won’t get into the intricacies of Kuhn’s philosophy of science. I will merely mention that it is much more nuanced than Weinberg seems to think.