Mises points out that “liberal philosophers” had utilitarian visions.
They constructed the vague image of a government whose only objective is to make its citizens happy. This ideal had certainly no counterpart in the Europe of the ancien regime. …
The state, as it appears in their writings, is governed by a perfect superhuman being, a king whose only aim is to promote the welfare of his subjects. (HA: 690)
Now if kings and bureaucrats do not seek “general welfare” but only their own, and individuals in the market also do not seek it, who then is motivated to care for social institutions and “good government”?
Mises answers that everyone is. A smoothly-functioning market economy benefits both all and each. Each citizen, in seeking solely his own welfare, has an incentive to promote good government (which usually translates into no government) because good government profits him personally even in his capacity as a regular citizen unprivileged in any way.
Conversely, if the whole society and economy are in danger or are falling apart, this harms everyone. Therefore, Mises wrote that “everyone carries a part of society on his shoulders; no one is relieved of his share of responsibility by others. And no one can find a safe way for himself if society is sweeping towards destruction. Therefore everyone, in his own interests, must thrust himself vigorously into the intellectual battle.” (Socialism: 515)
How strong this incentive of self-interest is, is another matter. Perhaps it needs to be supplemented by a sense of duty and charity.