The following is taken from 'Epistemological Problems of Economics' by Ludwig von Mises, from the section entitled 'The task and scope of the science of human action; Science and value'.
I think it's worth reflecting upon, as the issue of economics being value-free, which is discussed here, comes up quite often, usually in my case as a defence against an accusation of heartlessness or of despising the poor, when arguing against a particular act of state intervention. The free market liberal position meets with a great deal of hostility, but I believe this is mainly due to a misunderstanding of what that position really is and is not. Certainly it has been misrepresented by its opponents, and no doubt poorly represented by its adherents.
I recognise grappling with epistemological problems is not for everyone - but someone's got to do it! With a proper grasp of the fundamentals, it is then possible to convey the arguments to others in consistent, coherent and simpler terms.
Science and Technology: Economics and Liberalism
Whether science seeks knowledge for its own sake or in order thereby to obtain information for the sake of action, or whether it aims at both ends at the same time, it is in any case permissible to make practical use of the results of scientific investigation. Man thinks not only for the sake of thinking, but also in order to act. There would be no need to repeat these truisms were it not for the fact that antiliberal, partisan propaganda in the guise of science day after day vehemently seeks to deny them.
The fact that economics, as a science, is neutral with regard to judgments of value and that it can express neither approval nor disapproval does not prevent us from trying to learn from economics how we must arrange our action in order to achieve the ends at which we aim. The ends can be diverse. Caligula, who wished that the whole Roman people had but one head so that he might decapitate them at a single stroke, had different ends in mind from those of other mortals. However, such exceptional cases are rare; and their tendency to be self-destructive (Caligula, indeed, would hardly have long survived the fulfillment of his wish) makes an exhaustive concern with their ideals unnecessary. No matter how much their wishes, desires, and valuations may differ in details, men aim, for biological reasons, at the same basic ends. Regardless of world view, religion, nationality, race, class, position, education, personal abilities, age, health, or sex, they aspire above all to be able to pass their lives under the most favorable physiological conditions possible. They want to eat and drink; they seek clothing, shelter, and various other things in addition. Moreover, they are of the opinion that more food, clothing, and the like, is better than less.
Every individual desires life, health, and well-being for himself and for his friends and close relations. At the same time, the life, health, and well-being of others may be indifferent to him. Filled with the atavistic instincts of a beast of prey, he may even believe that others stand in his way, that they are depriving him of foraging grounds, and that the satisfaction of his wants must involve the killing and robbing of his fellow men. But the technology based on the cognitions of the science of human action shows him that this is not so. Work performed under the division of labor is more productive than the isolated labor of the individual. Even when superior men combine with those less favored in every respect and inferior to them in capacity for work and intellectual and physical abilities, both sides gain, as is demonstrated by Ricardo's law of association (usually called the law of comparative costs). Consequently, every individual is better able to attain his ends by the social cooperation of labor than by isolated work.
Social cooperation, however, can be based only on the foundation of private ownership of the means of production. Socialism - the public ownership of the means of production - would make impossible any economic calculation and is therefore impracticable. The absurdity of syndicalism is undisputed. As for interventionist encroachments, they prove - when judged from the point of view of those who advocate them - senseless and contrary to purpose, because they not only do not bring about the results desired by their supporters, but involve consequences that they themselves must deprecate.
Therefore, when one reaches the conclusion, strictly by adherence to the canons of scientific procedure, that private ownership of the means of production is the only practicable form of social organization, this is neither an apology for capitalism nor an improper attempt to lend the authority of science to the support of liberalism. To the man who adopts the scientific method in reflecting upon the problems of human action, liberalism must appear as the only policy that can lead to lasting well-being for himself, his friends, and his loved ones, and, indeed, for all others as well. Only one who does not want to achieve such ends as life, health, and prosperity for himself, his friends, and those he loves, only one who prefers sickness, misery, and suffering may reject the reasoning of liberalism on the ground that it is not neutral with regard to value judgments.
The defenders of the prevailing etatist and interventionist system completely misunderstand this. They think that the acceptance of liberalism, on the assumptions mentioned, presupposes a definite world view. Liberalism has nothing to do with world views, metaphysics, or value judgments.
We can imagine beings similar to men who would want to extinguish their humanity and, by putting an end to all thought and action, to attain to the unthinking, passive, vegetative existence of plants. It is doubtful whether there are or have ever been such men. Even St. Aegidius, the most radical advocate of asceticism, was not altogether consistent in his zeal for austerity when he recommended the birds and the fish as a model for man. To be entirely consistent, together with the Sermon on the Mount, he would have had to extol the lilies of the field as the embodiments of the ideal of complete abandonment of all concern for the improvement of one's lot.
We have nothing to say to men of this kind, consistent ascetics who by their self-denying passivity give themselves up to death, just as they would have nothing to say to us. If one wishes to call their doctrine a world view, then one must not forget to add that it is not a human world view, since it must lead to the extinction of mankind. Our science sees men only as acting men, not as plants having the appearance of men. Acting man aims at ends, i.e., he wants to overcome dissatisfaction as far as possible. Our science shows that aiming at ends is necessary to existence and that human ends, whatever they may be, are better attained by the social cooperation of the division of labor than in isolation. (It is worthy of note that no historical experience has been found in conflict with this proposition.) Once one has appreciated this fact, one realizes that no standard of value of any kind is contained in the system of economic or sociological theory or in the teachings of liberalism, which constitute the practical application of this theory to action in society. All objections to the effect that economics, sociology, and liberalism are predicated on a definite world view prove untenable once it is recognized that the science of action is concerned only with acting men and that it can say nothing about plant-like beings living with no thought of tomorrow, whom we can scarcely consider as human.
 E.g., Vleugel's "Probleme der Wertlehre," Archiv f?r Sozialwissenschaft und Sozialpolitik, LXVIII, 227f. Liberalism has no thought of denying the existence of servilism and its world view. All that liberalism endeavors to demonstrate is that the realization of the goals of servilism would necessarily bring about consequences of whose inevitability its advocates are in ignorance and which, even in their own eyes, must appear as too high a price to have to pay for the attainment of their ideal.