The world would have suffered no irreparable loss if the police had thrown the Sceptic's Walk into the fire. It is an allegory designed to contrast the life of religion, the life of philosophy, and the life of sensual pleasure. Of all forms of composition, an allegory most depends for its success upon the rapidity of the writer's eye for new felicities. Accuracy, verisimilitude, sustention, count for nothing in comparison with imaginative adroitness and variety. Bunyan had such an eye, and so, with infinitely more vivacity, had Voltaire. Diderot had not the deep sincerity or realism of conviction of the one; nor had he the inimitable power of throwing himself into a fancy, that was possessed by the other. He was the least agile, the least felicitous, the least ready, of composers. His allegory of the avenue of thorns, the avenue of chestnut-trees, and the avenue of flowers, is an allegory, unskilful, obvious, poor, and not any more amusing than if it's matter had been set forth without any attempt at fanciful decoration. The blinded saints among the thorns, and the voluptuous sinners among the flowers, are rather mechanical figures. The translation into the dialect required by the allegorical situation, of a sceptic's aversion for gross superstition on the one hand, and for gross hedonism on the other, is forced and wooden. The most interesting of the three sections is the second, containing a discussion in which the respective parts are taken by a deist, a pantheist, a subjective idealist, a sceptic, and an atheist. The allegory falls into the background, and we have a plain statement of some of the objections that may be made by the sceptical atheist both to revelation and to natural religion. A starry sky calls forth the usual glorification of the maker of so much beauty. "That is all imagination," rejoins the atheist. "It is mere presumption. We have before us an unknown machine, on which certain observations have been made. Ignorant people who have only examined a single wheel of it, of which they hardly know more than a tooth or two, form conjectures upon the way in which their cogs fit in with a hundred thousand other wheels. And then to finish like artisans, they label the work with the name of it's author." The defender justifies this by the argument from a repeater-watch, of which Paley and others have made so much use. We at once ascribe the structure and movement of a repeater-watch to intelligent creation. "No--things are not equal," says the atheist. "You are comparing a finished work, whose origin and manufacture we know, to an infinite piece of complexity, whose beginnings, whose present condition, and whose end are all alike unknown, and about whose author you have nothing better than guesses."