The earlier writings of Schelling either reproduced the thoughts of the Wissenschaftslehre or developed them in the Fichtean spirit. Among those of the latter class we note: Ideas for a Philosophy of Nature, 1797; On the World-Soul, 1798; System of Transcendental Idealism, 1800. During the second period, in which the influence of Bruno and Spinoza is prominent, he works out his own philosophy of identity; at this time he publishes Bruno, or, Concerning the Natural and Divine Principle of Things, 1802, and Method of Academic Study, 1803. In the third period the philosophy of identity becomes the basis for a still higher system in which the influence of German theosophy (Jacob Böhme) is apparent; with the exception of Philosophy and Religion, 1804, the Treatise on Human Freedom, 1809, and a few others, the works of this period did not appear until after Schelling's death. His previous philosophy is now called by him "negative philosophy;" the higher or positive philosophy has as its aim the rational construction of the history of the universe, or the history of creation, upon the basis of the religious ideas of peoples; it is a philosophy of mythology and revelation. Translations of some of Schelling's works are to be found in the Journal of Speculative Philosophy, an American periodical founded by W.T. Harris, which devoted itself to the study of post-Kantian idealism. His Complete Works, edited by his son, appeared in 14 volumes, 1856. There is a revival of interest in his philosophy, and new editions of his books are now being published.
Like most philosophers of note, Schelling reckons with the various tendencies of his times. With idealism he interprets the universe as identical in essence with what we find in our innermost selves; it is at bottom a living dynamic process. If that is so, nature cannot be a merely externalized obstacle for the ego, nor a dead static spatial mechanical system; as the expression of an active spiritual principle there must be reason and purpose in it. But reason is not identified by Schelling with self-conscious intelligence, for with the faith-philosophies and Romanticism he takes it in a wider sense; in physical and organic nature it is a slumbering reason, an unconscious, instinctive, purposive force similar to the Leibnizian monad, Schopenhauer's will, and Bergson's élan vital. In this way the dualism between mechanism and teleology is reconciled. Nature is a teleological order, an evolution from the unconscious to the conscious; in man, the highest stage and the climax of history, nature becomes self-conscious. With this organic conception both Romanticists and many natural scientists of the age were in practical agreement; it was the view that had always appealed to Goethe—and Herder before him—and it gained for Schelling a large following. In his earlier system he regarded nature as a lower stage in the evolution of reason and sought to answer the problems: How does Nature become Consciousness or Ego? the problem of the Philosophy of Nature; and, How does Consciousness or the Ego become Nature? the problem of Transcendental Idealism. In his philosophy of identity, nature and mind are conceived as two different aspects of one and the same principle, which is both mind and nature, subject and object, ego and non-ego. All things are identical in essence but differentiated in the course of evolution. It was not inconsistent with these tenets that Schelling sought, in his last period, to discover the meaning of universal history in the obscure beginnings of mythology and revelation rather than in the lucid regions of an advanced civilization.
With the opponents of rationalism Schelling agrees that we cannot reach the inner meaning of reality, "the living, moving element in nature," through the scientific intelligence, but that we must envisage it in intuition. "What is described in concepts," he tells us, "is at rest; hence there can be concepts only of things and of that which is finite and sense-perceived. The notion of movement is not movement itself, and without intuition we should never know what motion is. Freedom, however, can be comprehended only by freedom, activity only by activity." Schelling, who is a poet as well as a philosopher, comes to regard this intuition or inner vision as an artistic intuition. In the products of art, subject and object, the ideal and the real, mind and nature, form (or purpose) and matter, are one; here the harmony aimed at by philosophy lies before our very eyes, and may be seen, touched, and heard. The creative artist creates like nature in realizing the ideal; hence, art must serve as the absolute model for the intuition of the world—it is the true and eternal organ of philosophy. Like the artistic genius, the philosopher must have the faculty for perceiving the harmony and identity in the universe; esthetic intuition is absolute knowing. Art aims to reveal to us the profoundest meaning of the world, which is the union of form and matter, of the ideal and the real; in art alone the striving of nature for harmony and identity is realized; the beautiful is the infinite represented and made perceivable in finite form; here mind and nature interpenetrate. In creative art the artist imitates the creative act of nature and becomes conscious of it; in esthetic intuition, or the perception of beauty, the philosophical genius discovers the secret of reality; nature herself is a poem and her secret is revealed in art. This philosophy is a far cry from the logical-mathematical method of the Aufklärung; it is a protest against this, a protest in which the leaders of the new German literature, Herder, Goethe, Schiller, as well as the Romanticists, willingly joined. Goethe's entire view of nature, art, and life rested upon the teleological or organic conception; he, too, regarded the ability to peer into the heart of things—to see the whole in its parts, the ideal in the real, the universal in the particular, as the poet's and thinker's highest gift. He called it an aperçu, "a revelation springing up in the inner man that gives him a hint of his likeness to God." It is this gift which Faust craves and Mephisto sneers at as die hohe Intuition.
Dass ich erkenne was die Welt
Im innersten zusammenhält,
Schau alle Wirkungskraft and Samen
Und tu' nicht mehr in Worten kramen.
There was much that was fantastic in the Naturphilosophie and much a priori interpretation of nature that tended to withdraw the mind from the actualities of existence; it often dealt with bold assertions, analogies, and figures of speech, rather than with facts and proofs. But it had its merits; for it aroused an interest in nature and nature-study, it kept alive the philosophical interest in the outer world, the desire for unity, Einheitstrieb, which has remained a marked characteristic of German science from Alexander von Humboldt down to Robert Mayer, Helmholtz, Naegeli, Haeckel, Ostwald, Hertz, and Driesch. It opposed the one-sided mechanical method of science, and emphasized conceptions (the idea of development, the notion of the dynamic character of reality, pan-psychism, and vitalism) which are still moving the minds of men today, as is evidenced by the popularity of Henri Bergson, who, with our own William James, leads the contemporary school of philosophical Romanticists.
Fichte's chief contribution to German thought was the Wissenschaftslehre, Schelling's the Naturphilosophie, and Schleiermacher's the philosophy of religion. All these thinkers took account of the prevailing tendencies of the times—Aufklärung, Kantian criticism, faith-philosophy, Romanticism, and Spinozism—and were more or less affected by them. Schleiermacher also came under