"Take one little instance," he said. "We are a commercial world, and have built up a great system of credit. Without our cheques and bills of exchange and currency the whole of our life would stop. But credit only exists because behind it we have a standard of value. My Bank of England notes are worthless paper unless I can get sovereigns for them if I choose. Forgive this elementary disquisition, but the point is important. We have fixed a gold standard, because gold is sufficiently rare, and because it allows itself to be coined into a portable form. I am aware that there are economists who say that the world could be run on a pure credit basis, with no metal currency at the back of it; but, however sound their argument may be in the abstract, the thing is practically impossible. You would have to convert the whole of the world's stupidity to their economic faith before it would work. "Now, suppose something happened to make our standard of value useless. Suppose the dream of the alchemists came true, and all metals were readily transmutable. We have got very near it in recent years, as you will know if you interest yourself in chemical science. Once gold and silver lost their intrinsic value, the whole edifice of our commerce would collapse. Credit would become meaningless, because it would be untranslatable. We should be back at a bound in the age of barter, for it is hard to see what other standard of value could take the place of the precious metals. All our civilisation, with its industries and commerce, would come toppling down. Once more, like primitive man, I would plant cabbages for a living and exchange them for services in kind from the cobbler and the butcher. We should have the simple life with a vengeance--not the self-conscious simplicity of the civilised man, but the compulsory simplicity of the savage." I was not greatly impressed by the illustration. "Of course, there are many key-points in civilisation," I said, "and the loss of them would bring ruin. But these keys are strongly held." "Not so strongly as you think. Consider how delicate the machine is growing. As life grows more complex, the machinery grows more intricate and therefore more vulnerable. Your so-called sanctions become so infinitely numerous that each in itself is frail. In the Dark Ages you had one great power--the terror of God and His Church. Now you have a multiplicity of small things, all delicate and fragile, and strong only by our tacit agreement not to question them." "You forget one thing," I said--"the fact that men really are agreed to keep the machine going. That is what I called the 'good-will of civilisation.'" He got up from his chair and walked up and down the floor, a curious dusky figure lit by the rare spurts of flame from the hearth.