Archive for June, 2021


June 26, 2021

In his famous essay on ‘The Two Cultures” CP Snow pointed to the yawning divide in British Culture between Science and the Humanities. It’s still there, just as crippling as it was 60 years ago.

I was reminded of this when I started reading “The Boundless Sea – a human history of the oceans” by David Abulafia a professor of history at Cambridge University (Penguin 2019), a book which has attracted extravagant praise as well as The Wolfson History Prize for 2020. It’s a subject that has fascinated me since, as a boy, I read Thor Heyerdahl’s account of the Kon Tiki expedition — his raft trip across the Pacific in 1947 to explore his hypothesis that Polynesia might have been settled from South America.

That hypothesis gradually sank into disrepute following accumulating anthropological and genetic evidence suggesting that Polynesia was in fact settled not from the East but from the North by navigators of Asian descent. But then in 2020 came better DNA evidence showing that at least some South Americans had arrived in the Marquesas with their plants around 1150 AD. What has Abulafia to say about this evidence? On p 29 he writes that it:”… indicates that Polynesians from the Marquesas interbred with people from Columbia around 1150, most plausibly suggesting that Polynesians reached and returned from South America bringing Columbians and their seeds and tubers along with them.”

Heyerdahl’s balsa raft Kon Tiki sailing West from South America to Polynesia down the West Wind Drift powered by the Coriolis Force . Notice she’s got the wind behind her, as well as a current of 50 miles a day driven by the wind. Courtesy the Heyerdahl Museum in Norway.

What? Doesn’t Abulafia understand the winds and currents which would make such a hypothetical voyage thousands of times more difficult than Heyerdahl’s journey? Surely he understands the Coriolis Force which drives the Great West Wind Drift and indeed nearly all the voyages of exploration and trade around the globe in the days of sail?

So I skip to the Index, all of 63 pages long containing no less than 9,500 entries . No mention of Coriolis Force, and only one brief one to Trade winds, but not in the Pacific Ocean. But what about the maps, of which there are dozens and dozens? The Oceanic waters are entirely blank, no sign of the all-important currents and winds which drove and circumscribed all navigators in the days of sail.

One can only conclude that Abulafia either doesn’t know, or doesn’t understand the bearing of Science on the Oceans, a bit steep when he is writing a “Human history of the Oceans”. It’s like a geography text-book which omits all mention of mountains and rivers. The result is a timid history without any sweep or penetration, just another record of ‘One damn thing after another’ like his earlier book on the Mediterranean “The Great Sea” which I did manage to finish — just.

One could be more forgiving if Abulafia hadn’t been so condescending towards Heyerdahl , referring to him as a “self publicist” unworthy of his fame in Norway. Thor Heyerdahl wasn’t a timid academic, he was brave man who risked his life to explore his own imaginative idea — which as it happens, — turns out to be substantially right.

Abulafia’s egregious failure illustrates the folly of attempting history without comprehending or even taking notice of Science. And the extravagant praise for his book from other historians, and the award of the Wolfson Prize, can only suggest that such incestuos myopia is widespread in British academe. How can we rely on them when they must be writing for each other, and not for us?

But there’s a more general point here. It’s much easier to spot what is wrong with an argument than to spot what is missing from it. For instance the Scottish National Party is aiming to take Scotland out of the UK, without recognising that Scotland, with its 6000 miles of remote coastline, is indefensible on its own, but secure as part of a united island. How foolish. We islanders all need to sit up and take notice of that!


June 25, 2021

Common Sense Thinking needs some tool to discriminate between Truth and Falsehood, or more generally between sound hypotheses and unsound ones. ‘Hypothesis Testing’ ,as it is called, lives at the very heart of Science, Philosophy and Common Sense. As we now know it works by examining the various consequences C1 ,C2, …generated by that hypothesis to see whether they can be observed in practice. If they can be observed that improves our Odds O(H) on the hypothesis being true, if it cannot that reduces our Odds on it. But if the hypothesis generates no consequences we cannot test it , and so can say nothing about it one way or the other. That’s “Bayes’ Rule” which goes back at least as far as 1763 and probably much much further.

Take the hypothesis “God exists”. What consequences does it have? Once upon a time it was argued that the design of the natural world was so miraculous, perfect and improbable that it could only have been conceived by an Intelligent Creator. For instance how else to explain the spectacular plumage of the Rainbow Lorikeet ? [Click on the urls below to see their magnificence]

This was the very convincing “Argument by Design”, almost impossible to counter at the time. But in 1858 along came Darwin and Wallace who independently came up with the alternative hypothesis of “Evolution by Natural Selection”. As the Bishop of Worcester’s wife said of it: ” Dear me; let us hope it is not true. But if it is true , we must hope it doesn’t become widely known.”

The general point is that Inconsequential Hypotheses are hardly worth considering because there is no way of assessing their veracity, whereas Consequential Hypotheses are open to verification, at least in terms of their probability(Odds). Thus Evolution has subsequently been detected in, for instance, bacteria under stress , while I am not aware of any consequence for the existence of God which could be tested .

That’s not to say one can’t go on believing in a god — it’s just that the most consequential evidence on his/her hypothetical existence has an alternative, and partially verified explanation, even if it cannot be absolutely categorical.

Then there’s another important philosophical principle that can be brought to bear:Ockham’s Razor — “Always prefer the simpler hypothesis, because its more likely to be right’ [see my Post ‘Fuzzy Thinking & Common Sense’] .The problem with the God hypothesis is that there are so many inconsistent versions of it (4,000 known religions including 20 with a world-wide spread, according to Wikipedia).

Clever people have wasted a lot of their lives worrying about Inconsequential hypotheses — for instance the existence of Free Will [see Post. ‘Free Will and Common Sense] , or in the case of Mathematicians whether their subject was invented of discovered. It doesn’t matter. It’s Inconsequential.