the moral to be so intimate,(1005) that not only must account always be taken of the latter in estimating the unbelief of individuals, but the exclusive study of the former, without allowing for the existence of the latter, must be regarded as likely to lead to an imperfect and injurious idea of unbelief. The intellectual causes were however selected as the special subject of our study;(1006) partly because they have been much neglected by Christian writers, partly because they are the forms which for the most part create the doubts which Christians encounter in the present age. The principal intellectual causes were considered(1007) to be, either the new material of knowledge, such as the physical or metaphysical sciences, which may present truth antagonistic to the teaching of the sacred literature; or new methods of criticism, the application of which creates opinions differing from those of the traditionary belief; and, above all, the effects of the application of particular tests of truth,—sense, reason, intuition, feeling,—to the doctrines of revealed religion. This was our plan; and we have been employed in tracing the influence of these causes in generating doubt in the four great crises, with a minuteness which may almost have been tedious; endeavouring to supply the natural as well as the literary history; analysing each successive step of thought into the causes which produced it; searching for them when necessary in the intellectual biography of individuals; and, if not refuting results, at least laying bare by criticism the processes through which they were attained. At the same time we have attempted to show the grounds on which the faith of the church has reposed in the various ages of history. A defence, itself also twofold in its character—emotional and intellectual—has been generated by the attack in each of the crises, and an example thus furnished of the law which governs human society,—progress by antagonism. Permanent gain to truth was seen to be the result of the various controversies; quiet and refreshment after the discharge of the storm had cleared the atmosphere from the intellectual and moral ills with which it was charged. The utility of the inquiry will now, it is hoped, be apparent. Though these lectures must be regarded as instructive for the believer, rather than polemic against the unbeliever, yet they are intended to serve also a controversial purpose.