The most important works for a study of Coleridge’s philosophical views are the Friend, the Statesman’s Manual, Aids to Reflection, Coleridge On Logic and Learning, ed. by A. D. Snyder, and the Philosophical Lectures. His great philosophical work, the Opus Maximum, was never completed, though bulky manuscripts in the hands of the students to whom he dictated it survive in the British Museum and in the Huntington Library in California. His position was Platonic, owing something both to Plato and the Cambridge Platonists, in that he defended the objectivity and authority of the Idea with a capital I; it was Kantian and critical in that he wished to clarify the limits of knowledge. His philosophical thinking, though not systematized, is far more incisive than is frequently suggested by those who have not followed it through; publication of his philosophical marginalia is a desideratum, as he would have called it, and would reveal his penetrations in a sharper light than they have yet been seen. He displays a kind of metaphysical reasoning now in disrepute, but it is wrong to call him vague or mystical.
Coleridge as Philosopher, by J. H. Muirhead, is difficult, and written from Platonist hypotheses. In Kant in England, Mr. R. Wellek gives Coleridge, of all the writers dealt with, by far the longest treatment, biased in another direction. For those who read German perhaps the best critique is Coleridge and die Kantische Philosophie, Leipzig, 1933, by Dr. Elisabeth Winkelmann.