Obituary: Professor R. V. Jones

M. R. D. Foot's obituary of R. V. Jones [19 December] inevitably concentrated on his outstanding contribution to winning the war. I write as one of the thousands of students who were taught by him, writes Roger Lindsay.

"R.V." 's first-year Natural Philosophy course at Aberdeen taken by all Science, Engineering and medical students was the most wonderful mind- opening experience. It is the part, above all, of my degree course that I have had cause to recall; rarely for facts and always for approach. Intellectual rigour was central to all he did. Early on he emphasised to us "Occam's Razor", which, simply stated, says: "Accept the simplest explanation that fits all the facts at your disposal."

Whilst the science was rigorous, the lectures were FUN and many of them memorable for the way in which the practical demonstration lifted any clouds of misunderstanding and seared the principle on to the brain. Like the experiment to measure the speed of a bullet for which in front of an astonished audience he drew a service revolver from the folds of his gown and drilled the two rotating discs at the other end of the bench. The gunshot and the applause were deafening.

A full first-year turn-out of perhaps 200 students could be quite high- spirited. On one occasion a cornet began to be blown sporadically and tunelessly at the back of the theatre. Eventually and a little grittily, R.V. called the cornet-holder to descend to the front and then confiscated the instrument - but not before giving us a solo that would have done Louis Armstrong proud.

Another measure of his range, humour, concern for lucidity of thought and understanding of scientific principle came in his exam questions. For example, "If action and reaction are equal and opposite" (an oft-stated principle in physics), "how does a horse pull a cart?" Or, "If you have studied past Physics exam papers and observed any trends in the types of questions, state what the trend was, then set your own question and answer it."

In 1979, after watching a natural history television film of a sidewinder snake moving speedily across a desert at right angles to the direction pointed by its head, I thought to write to R.V. suggesting that explaining the movement of the sidewinder would make an excellent exam question. But I should have known! After kindly thanking me for my suggestion and clearly explaining in a few words what we both had seen on television and I had not understood, he revealed that he had anticipated my thought by some 30 years.

In 1949 he had set the following question:

"There are three things which are too wonderful for me, yea, four which I know not:

"The way of an eagle in the air; the way of a serpent upon a rock; the way of a ship in the midst of the sea; and the way of a man with a maid"

Proverbs xxx,18-19

What explanation would you give to Solomon for any three of the foregoing?

As a good Intelligence Officer, R. V. Jones stood by Occam's Razor, writes A. B. Sainsbury. He also perceived the truth of another law, defined by his colleague John Crow - "Do not believe what you wish to believe until you perceive what you ought to have perceived."

And then - and here whimsicality took over - he adumbrated Crabtree's Bludgeon, a fearful blunting of Occam's Razor: "No set of mutually inconsistent observations can exist for which some human intellect cannot conceive a coherent explanation, however complicated." In which case, he observed, all the Intelligence Officers can do is to stand by Occam. But Crabtree? Unmentioned by obituarists so far, he was Jones's greatest spoof, though his genesis was shared with a number of contemporaries, including a distinguished Professor of German and a subsequent Public Orator of London University.

He and his cronies at the Athenaeum created a fictitious character, 44 Christmases ago, as a joke on the literary fraternity to see how many of them would be honest enough to acknowledge that they had never heard of him. He is still commemorated by the annual Crabtree Oration, and it was for this some years ago that Jones mused on

the human tendency to seek complicated explanations that I have often seen in intelligence committees and elsewhere. It almost became necessary in Crabtree's case because, although we early orators took great care never to have Crabtree in two places at the same time, subsequent orators sometimes threw such caution to the winds

- which led to some bludgeoning.