They still do not allow what they see as short-term aberrations to undermine their faith in an unchallengeable system of laws which lay down how any efficient economy must operate.
The possibility of crisis
Karl Marx, by contrast, argued that the possibility of general crises of overproduction was built into the very nature of capitalism. He destroyed the arguments based upon Say's law in a couple of paragraphs in the first volume of Capital. Of course, he acknowledged, every time someone sells an article someone else buys it. But, argued Marx, once money is used to exchange goods through the market, it does not follow that the seller has then immediately to buy something else. Money acts not only as a measure of value in directly exchanging goods, but also as a means of storing value. If someone chooses to save the money they get from selling a good rather than spending it immediately, then there will not be enough money being spent in the system as a whole to buy all the goods that have been produced:
Nothing can be more childish than the dogma that because every sale is a purchase and every purchase a sale, therefore the circulation of commodities necessarily implies equilibrium of sales and purchases. If this means that the number of actual sales is equal to the number of purchases, it is mere tautology. But its real purport is to prove that every seller brings his buyer to market with him. Nothing of the kind. The sale and the purchase constitute . . . an exchange between a commodity-owner and an owner of money, between two persons as opposed to each other as the two poles of a magnet . . .
No one can sell unless some one else purchases. But no one is forthwith bound to purchase, because he has just sold. Circulation bursts through all restrictions as to time, place, and individuals, imposed by direct barter, and this it effects by splitting up, into the antithesis of a sale and a purchase, the direct identity that in barter does exist between the alienation of one's own and the acquisition of some other man's product. If the interval in time between the two complementary phases of the complete metamorphosis of a commodity become too great, if the split between the sale and the purchase become too pronounced, the intimate connexion between them, their oneness, asserts itself by producing-a crisis.5
The Dynamics of the System
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