Wilhelm von Humboldt, The Sphere and Duties of Government (The Limits of State Action) (1854 ed.) 
of the individual man, and the highest ends of his existence.
The true end of Man, or that which is prescribed by the eternal and immutable dictates of reason, and not suggested by vague and transient desires, is the highest and most harmonious development of his powers to a complete and consistent whole.
Freedom is the grand and indispensable condition which the possibility of such a development presupposes; but there is besides another essential,—intimately connected with freedom, it is true,—a variety of situations. Even the most free and self-reliant of men is thwarted and hindered in his development by uniformity of position. But as it is evident, on the one hand, that such a diversity is a constant result of freedom, and on the other, that there is a species of oppression which, without imposing restrictions on man himself, gives a peculiar impress of its own to surrounding circumstances; these two conditions, of freedom and variety of situation, may be regarded, in a certain sense, as one and the same. Still, it may contribute to perspicuity to point out the distinction between them.
“Germany’s greatest philosopher of freedom.” - Friedrich Hayek
Every human being, then, can act with but one force at the same time: or rather, our whole nature disposes us at any given time to some single form of spontaneous activity. It would therefore seem to follow from this, that man is inevitably destined to a partial cultivation, since he only enfeebles his energies by directing them to a multiplicity of objects. But we see the fallacy of such a conclusion when we reflect, that man has it in his power to avoid this one-sideness, by striving to unite the separate faculties of his nature, often singly exercised; by bringing into spontaneous co-operation, at each period of his life, the gleams of activity about to expire, and those which the future alone will kindle into living effulgence; and endeavouring to increase and diversify the powers with which he works, by harmoniously combining them, instead of looking for a mere variety of objects for their separate exercise. That which is effected, in the case of the individual, by the union of the past and future with the present, is produced in society by the mutual co-operation of its different single members; for, in all the stages of his existence, each individual can exhibit but one of those perfections only, which represent the possible features of human character. It is through such social union, therefore, as is based on the internal wants and capacities of its members, that each is enabled to participate in the rich collective resources of all the others. The experience of all, even the rudest, nations, furnishes us an example of a union thus formative of individual character, in the union of the sexes.