Main currents in American thought

The sturdy optimism that was a genial hallmark of the Victorian, was erected on more substantial foundations than a middle-class prosperity arising out of the Industrial Revolution; it was founded on a systematic philosophy, built of excellent materials and laid up with nice mortar-work, to which many hands contributed and in the finality of which many minds believed. Its master idea was the conception of growth, a conception that by contrast with the ideal of the static of earlier times, was profoundly revolutionary. Perhaps the most stimulating suggestion that came out of the Enlightenment, it was evolved by Turgot in France and by Price and Priestley in England, from the psychology of John Locke. If the human mind at birth is an empty vessel, wanting in innate ideas and waiting to be filled by sense perceptions, or if—to accept the familiar figure—it is a clean slate on which the finger of experience writes what it will, then it follows from the philosophy of Locke that the shaping of the individual is determined by the environment that cradles him. It is not an unfolding from within but a molding from without. Hence the idea of growth, and hence the vast preoccupation of the Enlightenment with sociology—or the science of environment—the hand of the sculptor that models the plastic clay. From such a conception the principle of progress was an inevitable deduction.