Schiller develops a Leibnizian sense of perfection as the unity of unity and multiplicity, and draws out its political implications. He defends a republican order of spontaneous beauty, emergent in freedom, against imposed perfection. In addressing the problems of the incipient modern division of labour and the prospects for political community, he defends variety against uniformity, while distinguishing historically progressive from regressive types of diversity. Schiller insists on processes of aesthetic self-formation and determinability, which make possible a mutual adjustment of interests as an achievable practical outcome, rather than as a metaphysical presupposition. Interests in modern civil society are diverse and troublingly fragmentary, but potentially reconcilable.

Leibniz defends teleology or purposive activity against the overly mechanical worldview of Thomas Hobbes, and develops an idea of spontaneity as self-originating action irreducible to mere mechanistic reaction. He links free activity with justice as the enabling conditions for the exercise of freedom, and with the progressive deployment of individual and collective powers. He thus sets the agenda for subsequent idealism, which reconfigures the idea of spontaneity and reflects on the harmonisation of diverse individual efforts as a problem of ongoing juridical reform

Marx’s early theory of labour and alienation originates from idealist concepts of spontaneity and formativity. His ideas of socialism and emancipation in the 1840s reprise aspects of Kantian autonomy and heteronomy and follow Fichte in linking labour with spontaneity. Marx formulates the dialectic of the will in a way favourable to the moment of particularity as membership in a social class, and sees one particular class as simultaneously a vehicle of universal interest and revolutionary transformation. Quantitative change is insufficient though necessary: a merely distributive socialism might enhance the living conditions of the workers, but would leave intact structures of exploitation which deprive workers of their agency as well as their happiness. His theory of history and emancipation, recently described as a self-actualisation account, can be more precisely identified as a variant of post-Kantian perfectionism, which, like Feuerbach’s, contains a strong admixture of pre-Kantian elements. This blending of heterogeneous elements has profound theoretical and practical consequences, notably in the absence of a developed concept of right.

The concept of post-Kantian perfectionism clarifies the mutual polemics in the Hegelain School, contrasting Feuerbach’s naturalism, which combines pre- and post-Kantian motifs, with the more exigent Kantianism of Bruno Bauer; and it elucidates sharp disagreements with anti-perfectionists like Max Stirner. The concrete historical situation comes under scrutiny of post-Kantian perfectionist thinking. French Revolutionary factions and the contending parties in the German Vormärz express distinct views of freedom and follow different developmental trajectories. Civil society too reveals its inner dynamics. Rejecting Leibniz’s pre-established harmony and Wolffian mutuality, but also markedly differing from Kant and Schiller, the non-compossibility of interests in civil society is the theoretical innovation here. The irreconcilable opposition of interests, central to Marx, is not a view original with him. In Bauer, autonomy means divesting oneself of particular interests to the extent that they inhibit institutional transformation.