The will could not experience an actual development of freedom if it were not possible for it to negate its essence. The subjective will must be able to separate itself from the essential, must be able to fall away from the Idea of freedom. The will must therefore determine itself as freedom of choice or as the ability to choose between opposite ends. The antinomy between the proposition that the will can only determine itself toward its Idea, and the opposite, that it can also negate it, is annulled by the recognition that the latter contains the negative condition for the actuality of the former. Only by overcoming the possibility of its opposite can freedom actually substantiate itself.
– Hans L. Martensen: ‘Outline to a System of Moral Philosophy’, 1841