BRITAIN’S gas and oil reserves are running out. News this week that contracts are being secured for the purchase of huge quantities of frozen gas from Indonesia, ship-delivered over the coming decade, will come as no surprise to anyone in the business, nor in government. When gas and oil were first discovered around us, nobody knew quite how long they would last; but everybody knew they were finite.

Let us tot up just a selection, a sample, of those things that nobody knows. Nobody knows how the prices of different sources of energy will move against each other in the years ahead; the higher the prices the more furiously we shall prospect for new reserves and the more worthwhile it will become to exploit existing reserves that are at present uneconomic or marginal. But one day — nobody knows when — there will be nothing left.

Nobody knows what alternative means of generating heat and power may be invented or developed, nor what breakthroughs in efficiency or cost-effectiveness may be achieved. Nobody knows how wars or civil commotions may distort or disable parts of the energy market. Nobody knows what warning we may get of any of this.

Nobody knows much. Key imponderables could wreck the most assiduously prepared spreadsheets. It is like British weather-forecasting. As any meteorologist will tell you, many variables are predictable in principle, but in practice the outcome — the weather — rides so delicately upon an interplay between so many fast-moving variables that the slightest inaccuracy in our guesses about any one of them can throw the whole forecast out.

So how do we prepare for the weather? Packing for an August week in Cornwall, do we study the forecast then on the balance of probabilities assume sunshine — or storm? No. We take sun-cream and an umbrella — and throw in the swimsuit just in case. We are all too aware, from personal experience, of how flimsy is human knowledge.

This is not anti-science, it is superior science: a calculation that gives proper weight to uncertainties, then balances the cost of providing for each possible outcome against the cost — should it occur — of having failed to provide for it. This is quite sophisticated reasoning but we engage in it, mostly unconsciously, all the time. It is common sense: perhaps the most important of all pieces of common sense: taking proper account of what we do not know.

I wonder whether the business and political culture of the century on whose threshold we stand is losing grip on this common sense: the weight we should attach to the gaps in our knowledge? J. K. Galbraith, in a new and lucid little book, The Economics of Innocent Fraud, puts it like this: “The financial world sustains a large, active, well-rewarded community, based on compelled but seemingly sophisticated ignorance, (who) . . . do not know and normally do not know that they do not know.”

I observe this to be a failing particularly prevalent among accountants. Theirs is a career at whose centre are pieces of paper or (these days) screens. On the screens are columns and boxes. Against the columns, or in the boxes, figures have to be placed. Mathematics is then performed upon the figures; and “bottom lines” are derived.

Heartsinking for an accountant are two kinds of default: a blank box, or figures that do not add up. Either default spoils his spreadsheet, and does so in a way which is straightforward, demonstrable and evident at once to his bosses and peers. There may be other people (perhaps in the world beyond his business) who might question the contents of one or another of the boxes, or prefer that it be left blank because it is uncertain, but that is only an opinion: the accountant may feel that it is not quite his concern. A spreadsheet in which no entry is left blank and everything adds up is much to be preferred to something with white spaces all over it and no bottom line.

Thus is presented a document that gives every appearance of good information and sound numbers. Of course even this will in the end be tested against reality: bankruptcy is also part of an accountant’s experience. But when that happens an accountant’s instinct will often be to conclude that the world has failed his spreadsheet rather than the other way round. One of his neat boxes was badly let down by something — a war, a flood, an economic downturn — which nobody could have predicted. Too bad.

An engineer’s existence has at its centre something quite different. Damns can break, bridges can fall, planes can crash, power can fail. When this happens it is often, immediately (and sometimes dramatically) the engineer’s fault. Engineers use spreadsheets too, but if an empty box on a spreadsheet cannot be filled without guesswork then the engineer feels a more lively sense of dread than the accountant.

We live in a world of boardrooms where, in authority if not in numbers, the accountants have taken over from the engineers. The bean-counters rule.

I offer energy as an example. Any fool can see that enormous uncertainties attend Britain’s (and the West’s) future supplies of hydrocarbons. “Alternative” has such a silly ring these days, suggesting yoghurt and Morris dancing, so let us say “other”: any fool can see that in a broad and general sort of way, for broad and general sorts of reasons, we should be pushing urgently ahead with the development and use of other sources of power.