In the educated and cultivated man this power of judging probabilities, of testing beliefs by their rationality, is carried, or is capable of being carried, to the highest point of development, so as to comprehend in the calculation the full elements of the question, or at least to reduce the danger of some fatal omission to the minimum. It is, of course, true that the limited range of our faculties may prevent a full view of all the elements of any question of probability, even when our faculties have attained the highest point of development experienced by the age in which we happen to live. This renders the rationality of any hypothesis less than an absolutely certain test of truth. But this rationality is all that we have to apply to any question of belief; and if we attend carefully to the fact that moral probabilities constitute the groundwork of all our beliefs, and note the mental processes by which we reach conclusions upon any question depending upon evidence, we shall find reason to regard this power of testing beliefs by a conformity between the hypotheses and that which is most probable to be the most glorious attribute of the human understanding, as it is unquestionably the safest guide to which we can trust ourselves. It may be that, while philosophers will not object to my definition of rationality, churchmen will ask what place I propose to assign to authority in the formation of beliefs. I answer, in the first place, that I am seeking to make myself understood by plain but reflecting and reasoning people. Such persons will perceive that what I mean by the rationality of a belief in any hypothesis is its fitness to be accepted and acted upon because it has in its favor the strongest probabilities of the case, so far as we can grasp those probabilities. I know of no other foundation for a belief in anything; for belief is the acceptance by the mind of some proposition, statement, or supposed fact, the truth of which depends upon evidence addressed to our senses, or to our intellectual perceptions, or to both. In the next place, in regard to the influence of authority over our beliefs, it is to be observed that the existence of the authority is a question to be determined by evidence, and this question, therefore, of itself involves an application of the test of rationality, or conformity with what is probable. But, assuming that the authority is satisfactorily established, it is not safe to leave all minds to the teaching of that authority, without the aid of the reasoning, which, independent of all authority, would conduct to the same conclusion. There are many minds to whom it is useless to say, You are commanded to believe. The question instantly arises, Commanded by whom, or what? And if the answer is, By the Church, or by the Bible, and the matter is left to rest upon that statement, there is great danger of unbelief. It is apparent that a large amount of what is called infidelity, or unbelief,