2 JUNE 1961, Page 15


SIR,—May I be allowed a brief reply to Dr. Herman Kahn's comments on my review of his book?

I do not disagree with his fundamental motives, nor did I intend to attack them in my review. I did not gather (as some readers appear to have done) that he enjoys the prospect of nuclear war, or even of a 'doomsday machine.'

My main complaint was that the large amount of research work underlying his conclusions appeared to consist of extensive calculations based on shaky or unrealistic assumptions. Such an approach may be dangerously misleading, because the impressive superstructure of formulae, charts and technical terms tends to obscure the weakness of the foundations. One cannot, of course, argue out in your columns the validity of all the argufnents, but I gave a few examples of the kind of statement which made me so suspicious of the assumptions used.

Dr. Kahn comments only on one of these examples. This concerned the calculation of the productive capacity of a country after a thermo- nuclear attack. I am not comforted by the further explanation that these were 'derived from a simple eleven-component input-output model of the economy' and checked by a larger twenty-one-com- ponent model. I am not satisfied that any understand- ing of the human, psychological and 'organisational problems of such a situation has gone into any of these models. Experts often fail to predict the response of a community, or of an economy, to far less drastic happenings. How much harder to find valid equations for such a completely unprecedented situation. And how little is said about the way this has been approached. Let twenty-one average people sit around a table and each guess what is going to happen. I suspect the answers will be about as reliable as those of the twenty-one-component model.

The writings of scientists, particularly those in places like the RAND Corporation (to us outsiders, I insist, their set-up does seem strange, but no insult intended), are now read by many non-scientists, who may not be capable of unearthing the logic and the assumptions below the superstructure. The thought of the misappraisal which may result is disturbing. Let us keep our calculations as rough and simple as the roughness of our assumptions warrants, other- wise we are liable, in the words of a memorable war- time phrase, to 'blind the b-s with science.'--Yours faithfully,