Ludwig von Mises
Conception and Understanding
5. Logic and the Social Sciences
In the last generation the Instinctive logic of the social sciences was confronted with two tasks. On the one hand, it had to show the distinctive peculiarity, the feasibility, and the necessity of history. On the other hand, it had to show not only that there is, but also how there can be, a science of human action that aims at universally valid cognition. There can be no doubt that a great deal has been accomplished for the solution of these two problems. That these solutions are not "final" or "definitive" is evident, for as long as the human mind does not stop thinking, striving, and inquiring, there is no such thing as "finality" and "definitiveness."
The demand is repeatedly made by those who champion political ideals that cannot be defended by logical argumentation that thinking in the field of the social sciences be exempted from the regulative principles necessary to all other thinking. This is a matter with which scientific thought, which considers itself bound by these logical principles, is unable to concern itself.
When, more than a century ago, Sismondi appeared on the scene against Ricardo, he declared that political economy is no "science de calcul," but a "science morale," for which he enunciated the proposition: toute abstraction est toujours une d?ception. Neither Sismondi nor the many who have taken over this clich? have divulged to us the secret of how science could be pursued without abstract concepts. Today, the "living concept," which has the power to take on new content, is recommended to us as the most recent product of the logic of the social sciences. In the programmatic declarations that introduce a new Zeitschrift f?r geistige und politische Gestaltung, issued by a circle of German university professors, we read:
Concepts are living only so long as they have the power to take on new content. Taking on new content does not mean shedding the old, nor does it mean breaking away from the sources that gave rise to the concept. Taking on new content means, on the contrary, the power of a concept, and through it the power of its source, to prove that it is able to overcome every threat of rigidity.
That, using concepts of changeable content, one can argue excellently and can even concoct a system is certainly to be conceded. We "understand" very well the need of certain political parties for such makeshifts. However, the only thing that it concerns us to establish here is that this is not a need of scientific thought engaged in the cognition of social phenomena, but the need of political parties that are unable to justify their programs logically. Today these parties are striving for world dominion with good prospect of success. The masses follow them, the state has handed over all the schools to them, and the literati praise them to the skies. These facts make it all the more necessary to repeat the truism that there is only one logic and that all concepts are distinguished by the unequivocalness and immutability of their content.
 Sismondi, Nouveaux principes d'?conomie politique (Paris, 1819), 1, 288.
 Cf. Tillich, "Sozialismus," Neue Bl?tter f?r Sozialismus, (1930), I, I.