Criticism has been freely levelled at this extravagant importance which capital is made to assume. It is certainly somewhat curious that labour should now be treated as altogether subordinate to capital, whereas earlier in the volume labour alone was regarded as the great wealth-producing agent. But we are not here concerned with the revival of these threadbare controversies.[167] We merely wish to note that Smith finds in this accumulation of capital a new illustration of spontaneity. The saving of capital is not the result of any foresight on the part of society, but is solely due to the simultaneous and concurrent actions of thousands of individuals. These individuals, urged on by a desire to better their situation, are spontaneously urged to save their earnings and to employ those savings productively. “The principle which prompts to save, is the desire of bettering our condition, a desire which, though generally calm and dispassionate, comes with us from the womb, and never leaves us till we go into the grave.… An augmentation of fortune is the means by which the greater part of men propose and wish to better their condition. It is the means the most vulgar and the most obvious; and the most likely way of augmenting their fortune, is to save and accumulate some part of what they acquire.” This desire is so powerful that even the greatest follies perpetrated by Governments have never succeeded in annulling its beneficial effects. “The uniform, constant, and uninterrupted effort of every man to better his condition, the principle from which public and national as well as private opulence is originally derived, is frequently powerful enough to maintain the natural progress of things toward improvement, in spite both of the extravagance of government, and of the greatest errors of administration. Like the unknown principle of animal life, it frequently restores health and vigour to the constitution, in spite, not only of the disease, but of the absurd prescriptions of the doctor.”[168] But the idea of the spontaneity of economic institutions finds its most interesting illustration in the theory of demand and supply, upon which we must dwell a little.