"Modern industry, in fact, is a kind of rape. All the long astronomical and geological ages during which the materials which we find useful have been built up, contribute a moment's blaze, a moment's frivolous exuberance. But when his fireworks are finished, what will become of industrial man? All this, of course, does not appear in practice in the tragic and catastrophic form in which I have been stating it. What we know is that the price of coal goes up, and we do not readily connect this fact with the second law of thermodynamics. If you look up this law in a textbook, you will learn that it states that entropy always increases, and if you are not a physicist you will not be much the wiser. But the law can be stated more simply, and is stated more simply by proverbial wisdom. It states, in fact, that you cannot unscramble eggs. It deals with all the irreversible processes of nature. Some processes are reversible, some are not. If you travel from London to Edinburgh, you can also travel from Edinburgh to London, but if coal is used to make your train go, there is no way by which you can collect the heat which it generates, and turn it back into coal. If you shuffle a pack of cards, you can, if you take enough trouble, unshuffle them again, but if you drop a drop of ink into a glass of water, the ink will gradually spread throughout the water, and there is no way by which you can collect it back again into a drop. All industry depends upon such irreversible processes; it all uses up the earth's capital. Modern industry is, in fact, a spendthrift, and sooner or later must suffer the penalty of spendthrifts."