ONE IMPORTANT practical problem is to determine how to obtain relevant measurements. People talk about "imponderables" as if they were small demons lurking in their offices. Indeed, if one says:."I must know what is going to happen on the 13th of June next year", one must realize that there is no means of knowing. There is no point in asking absurd questions which, in the nature of things, cannot be answered, and then setting a wail about imponderables. A better approach, better because it works, is to invite the scientist to examine the problem situation from every possible slant, reshuffling it as it were, in search for a commensurable approach. The scientist will look for some critical feature of the situation that is on the face of it measurable, and he will try to find a metric which fits it. I will give you an example.
There is a narrow channel between Denmark and Sweden, which provides the only entrance to the Baltic. The narrowest crossing is between Helsingq~r in Denmark, and H~ilsingborg in Sweden. We Scandinavians transport ourselves and our goods freely across the Sound. The journey by ferryboat takes less than half an hour, and little fuss is made about such formalities as passports. Now this cross-channel traffie is steadily increasing, and so is the sea-going traffic between the Baltic and the outside world. Thus there is an increasing congestion in the channel; and obviously an increasing risk of collision.
The Governments of Denmark and Sweden set up a joint Commission to investigate this situation. In particular, there could well be a bridge between the two countries. Con-sider~ said the Commission, the state of affairs when the traffic in both directions has doubled. Needless to say, it is not very difficult to make a statistical forecast of the date when this will occur, nor is it difficult to support the statistical extrapolation by arguments from the plans and intentions of all concerned. Clearly one of the factors, the risk of collision, will be increased, compared with the risk today. The layman might very well imagine that when the traffic is doubled, the risk of collision is also doubled; on the other hand, he might very well wonder whether this would be true. In any case, it is very likely that the layman would suppose that no conceivable way of computing this risk could be obtained -short of running an experiment, whether in the water or by computer simulation~ in which a doubled traffic was allowed to run. But an experiment in the water is clearly impracticable, for it would take an enormous amount of organization and of money, even if it could be done. A computer simulation may well be impracticable too, for the very good reason that collisions depend in the last resort on the failure of human beings standing on ships' bridges to avert them. It is very difficult indeed to say what role will be played *With permission of Stafford Beer | have used part of his English version of my early presentation of this work given in a seminar.