Where Inness showed himself superior to the American painters of his early life was in the comprehensive control which he exercised over his view of nature; a control assisted by his close study of nature’s forms, and of their relative significances. He was, in fact, the father of the naturalistic movement in American landscape; for it seems clear that he fully realized the trend of his studies before he had found them indorsed by the Barbizon painters. And this separate and independent offshoot of the naturalistic movement, appearing almost simultaneously in the New World, is a very curious and interesting problem. In the case of the Barbizon painters the logic of the movement can be readily traced: in the general dissatisfaction with classicism; in the immediate influence of Constable and the tradition of the Dutch; and, finally, in a sort of compromise between the realism of Courbet and the poetic rage of the Romanticists. But that, unprompted by outside suggestion, a yearning for nature study and for a poetic interpretation of landscape should have arisen at about the same time in a young man on the banks of the American Hudson, points to that wider logic which thinkers have detected in the evolution of man--that the identical phases of evolution may appear sporadically, independent of transmitted causes, the individual man or nation having reached a period of personal development at which the next step becomes inevitable.
Inness was of religious temperament; highly imaginative and at the same time questioning, argumentative, as befitted his Scotch origin. Applying these qualities to his art, he was unremitting in the investigation of truth, while regarding nature in a spirit of elevated poetry. For he seems to have had always an alert consciousness of the simultaneous claims of the spirit and of the senses. He found an interdependence between the two. External beauty was the expression of an inward beauty of spirit. In this way landscape painting to some orders of mind becomes veritably a form of religious painting. It would seem to have been so to Inness, as, in his way, it was to Corot. It was with the latter of all the Barbizon painters that Inness appears to have had most sympathy, though he was appreciative also of Rousseau and Daubigny.