Now, the method which in the natural sciences, and in the science of language, has led to such vast results, may be, and ought to be pursued here. This method is that of comparison.
When the philologist is desirous of discovering what elements, if any, a group of languages possesses in common, and what therefore may be considered as its fundamental stock, or essence, he compares them with one another. When the naturalist wishes to arrive at an accurate knowledge of the conformation, habits, or character of any class of animals, he can only do so by a comparison of different members of that class. How misleading our conclusions frequently are in matters like these when they are not based upon a sufficiently wide comparison, will be familiar to all. And though the analogy between these sciences and religion is far from precise, yet no good reason can be assigned why a method, which has been so successful in one case, should be totally neglected in the latter. Nor is it enough to say that this method is capable of application to the subject in hand. Religion, owing to certain characteristics which will now be explained, lends itself with peculiar facility to an inquiry thus conducted.
A merely superficial and passing glance at the phenomena presented to us by the history and actual condition of the world brings clearly to light two facts:
1. The absolute, or all but absolute universality of some kind of religious perception or religious feeling.
2. The countless variety of forms under which that feeling has made its appearance.
History and the works of travelers, amply prove that no considerable nation has ever been without religion, and that if it has ever been wanting, it has only been among the rudest savages, whose mental and moral condition was too low to be capable of any but the most obvious impressions of sense. Equally indubitable is the second proposition. We are acquainted with no period in which each country did not possess its own special variety of religious doctrine; we are acquainted with none in which there were not many and wide divergences within the bosom of each country among individuals, among sects, and among churches.
In this universality of a certain sentiment, accompanied by this variety of modes, we have at least a possible distinction between the Substance and the Form, between the universal emotion known as Religion, and the local or temporary coloring it may happen to assume.
It will be convenient if we call the substance by the name of Faith, and the form by that of Belief. The use of these terms in these senses is no doubt slightly arbitrary, yet the shade of difference in their ordinary meaning is sufficient to justify it. Faith is a term of large and general signification, referring rather to the feelings than the reason; whereas Belief generally implies the intellectual adoption of some definite proposition, capable of distinct statement in words.
The importance of the comparative method in the process of sifting, classifying, and ordering the elements of these respective spheres will now be apparent. For it is only by a comparison of the varieties of Belief that we can hope to arrive at an acquaintance with Faith. Setting one system beside another, carefully observing wherein they differ and wherein they agree, we may at length hope to discover what elements, if any, are to be set down to the account of Faith, and what other elements to that of Belief. Even after a full comparison there will still be considerable danger that we may mistake tenets which are widely held, but not universal, for primordial conceptions of the human mind. Without such a comparison, we should most undoubtedly do so, for we are ever unwilling to recognize how wide are the limits of variation of which the opinions and sentiments of men are capable.
Should we, however, succeed in eliminating by our analysis all that is local, and all that is temporary, we shall possess, in what remains to us after this process, a universal truth of human nature. Observe that I speak here of a truth of human nature as distinguished from a truth of external nature. The one does not of necessity imply the other, for it is conceivable that men might universally entertain certain hopes, fears, aspirations, or convictions which were wholly groundless; the supposed objects of which had no existence whatever beyond the mind that entertained them. In the present case, then, all that the most exhaustive comparison could do would be to lead us up to the scientific fact, that there is in human beings an irresistible tendency towards certain sentiments of a spiritual kind. Whether those sentiments can be the foundation of any rational conviction it is unable to tell us.