Indeed biographical notices, if they could be extended compatibly with the compass of the subject, would be the most instructive and vivid mode of presenting alike the facts relating to scepticism and their interpretation. Such memoirs are not wanting, and are among the most touching in literature. The sketch which Strauss has given of his early friend and fellow student Maerklin,(113) gradually surrendering one cherished truth after another, until he doubted all but the law of conscience; then devoting himself in the strength of it with unflinching industry to education; until at last he died in the dark, without belief in God or hope, cheered only by the consciousness of having tried to find truth and do his duty:—the sad tale, told by two remarkable biographers, of Sterling,(114) doubting, renouncing the ministry, yet thirsting for truth, and at last solacing himself in death by the hopes offered by the Bible, to the eternal truths of which his doubting heart had always clung:—the memoir of the adopted son of our own university, Blanco White,(115) a mind in which faith and doubt were perpetually waging war, till the grave closed over his truth-searching and care-worn spirit:—the confessions of one of our own sons of the successive “phases of faith”(116) through which his soul passed from evangelical Christianity to a spiritual Deism, a record of heart-struggles which takes its place among the pathetic works of autobiography, where individuals have unveiled their inner life for the instruction of their fellow-men:—all these are instances where the great moral and spiritual problems that belong to the condition of our race may be seen embodied in the sorrowful experience of individuals. They are instances of rare value for psychological study in reference to the history of doubt; sad beacons of warning and of guidance. Accordingly, in the history of free thought we must not altogether neglect the spiritual biography of the doubter, though only able to indicate it by a few touches; by an etching, not a photograph. We have now added to the explanation before given of the province of our inquiry, and of the law of the action of free thought on religion, an account of the moral and intellectual causes which operate in the history of unbelief, and have sufficiently explained the mode in which the subject will be treated. The use of the inquiry will, it is hoped, be apparent both in its theoretical and practical relations. It is designed to have an intellectual value not only as instruction but as argument. The tendency of it will be in some degree polemical as well as didactic, refuting error by analysing it into its causes, repelling present attacks by studying the history of former ones.