The essential thing in the enlightenment acquired by philosophical study is the appreciation of the fact that understanding, enlightenment, science, etc., are not cultivated for their own sake, but must serve the purpose of human development, the material interests of which demand a correct mental picture of the natural processes. We have chosen the religious idea for discussion in this chapter so that it may serve as a means of illustrating the nature of thought in general. We regard it as the merit of philosophy to have unveiled this nature. Professor Lazarus is quite a pleasing companion. He is a fine thinker, saturated with the teachings of the philosophers, not overfond of any particular school, and only about two hands' breadth removed from our position. But this is just enough to demonstrate by his shortcomings the advantages of our position which proves that the part of the human soul performing the work of thinking is understood by us at least two hands' breadth better than by this prominent psychologist. "The function of enlightenment is to recognize that no phenomenon can be an effect which has not another phenomenon as its cause, and to search for the sole cause of every effect, noting all its parts and their consecutive divisions." These words describe the mental work performed by the human brain fairly well, but still they require a little addition, to the effect that the mental work is no exception from any other phenomena, all of which have not alone their special, but also one general cause. The cause of all causes, of which religion is making an idol, must be profaned, so to speak, by the cult of science, so that the above definition of Lazarus regarding enlightenment would read as follows: The sole and true cause of all effects is the universe, or the general interdependence of all things. But this is not by far the full scope of enlightenment. It is further necessary, as Lazarus well says, to note "all its parts and their consecutive divisions." We further add: The universal cause must be understood not alone in its consecutive parts, but also in its co-ordinate parts. It is only then that understanding, enlightenment, become perfect. We then find that after all the relation between cause and effect, or the relation between the universal truth and its natural phenomena, is not a very trenchant one, but a relative one. "Enlightenment advances in various, in all, fields of mental life. Religious enlightenment has long been recognized as the most essential, justly so, and for many reasons, the chief of them being that religious enlightenment is the most important and hence the most bitterly contested."