In connection with the review I am writing of Rüdiger Safranski's book on the friendship between Goethe and Schiller, I have been reading Safranski's earlier biography (2004) of Schiller, subtitled "The Invention of German Idealism." Safranski puts flesh, as it were, on philosophical ideas, breaking them down into digestible portions. Kant spoke of his "critical" apparatus as a family tree (Stammbaum), but Safranski describes it instead as a "Rococo-like music box construction of our faculties of perception and knowledge, with the various kinds of judgment attached to their respective categorical levers (thus, judgment of quality is attached to the categories of 'reality, negation, limitation')."
Kant was not the only philosopher with whom Schiller grappled, and Safranski makes a great tour of the "worldly philosophers" of the 18th century, especially the Scottish philosopher Adam Ferguson (in the portrait here by Joshua Reynolds in the NGA, London) whose Institutes of Moral Philosophy (1769) was translated by the German Enlightenment philosopher Christian Garve. Schiller's medical training as a young man greatly impressed on him the material nature of humans. Although he had "lost religion" early, he was unwilling to accept the determinism inherent in purely mechanistic or materialist philosophies as explanations for human behavior. In his youth already, he would not accept that humans did not have freedom of action or will. In his earliest attempt "to save freedom in the physiological machine," namely, in the dissertations he wrote at the end of his medical training, he posited love as a mediating power (Mittelkraft) that closed the gap (Riß) between material world and spirit.
For this "philosophy of comic love" to operate, life has to be breathed into the "machine" (i.e., the body), thereby allowing spontaneity and freedom. Schiller developed his theory of attentiveness, which, according to Safranski, led Schiller to becoming the philosopher of freedom.
In determinist theory, as Schiller learned from his reading of Ferguson, sense impressions generate conceptions, which in turn determine thinking and action. This scenario suggests that everything is causally ordered and that freedom is an illusion. "But here," writes Safranski, "begins the power of attentiveness. It is like an agile [bewegliche] ray of light, which, led by an intention, scans [abtastet] the fields of perception, fixes on something here, passes over something there; it selects, guides the processes of thinking, and gives rise to connections: in short, 'the soul has an active influence on the organ of thought.' It has this influence, because the soul is the active subject of attentiveness."
So begins, as Safranski writes, "the invention of German idealism."