[T]he message of Thoreau, though his fervency may be inconstant and his human appeal not always direct, is, both in thought and spirit, as universal as that of any man who ever wrote or sang — as universal as it is nontemporaneous — as universal as it is free from the measure of history, as ‘solitude is free from the measure of the miles of space that intervene between man and his fellows.’ In spite of the fact that Henry James (who knows almost everything) says that ‘Thoreau is more than provincial — that he is parochial,’ let us repeat that Henry Thoreau, in respect to thought, sentiment, imagination, and soul, in respect to every element except that of place of physical being — a thing that means so much to some — is as universal as any personality in literature. That he said upon being shown a specimen grass from Iceland that the same species could be found in Concord is evidence of his universality, not of his parochialism. He was so universal that he did not need to travel around the world to prove it.
Charles Ives, on Henry David Thoreau [pictured], Essays Before a Sonata (1920).