Theism. Fallacies from confusion between Tests of Speculative and of Practical Truth. Lesson of Mathematics. Speculative truths tested by analytic process; Practical by synthetic; their work becomes their ever-growing verification. Application of this test to two practical beliefs; our natural belief in externalities, and our belief in the Supernatural. Speculative difficulties intruded into the practical sphere become apparently insuperable. Both spheres essentially Human. Natural Realism compared with Realistic Theism. Formation and growth of Belief in the Supernatural as a Belief of Reason. Absurdities attaching to its rejection. Ennobling influences of its acceptance explained and exemplified. Ideal of Humanity, crowned by the Ideal of God, to Whom both the Natural and the Moral world bear witness. CHAPTER IV. BELIEFS OF REASON. In the last section, we have examined a number of intellectual perplexities, running closely parallel to certain _primâ-facie_ objections commonly alleged against Natural Theism. We have seen that they are, in reality, difficulties arising from the impotence of the Human Mind, whenever it is directed to the contemplation of first or supreme, Principles. In all reason therefore, they cease to be objections. We are, in fact, constantly finding ourselves obliged to accept as an undeniable truth, or a real existence, what when placed objectively before our mental vision, appears inexplicable, self-contradictory, or absolutely unthinkable. The power which compels us to many an admission of this kind is the _mind itself_, asserting a strength of insight, in-born and inalienable, notwithstanding the symptoms of weakness, which (psychologically speaking) may have seemed threatening to overcloud and disable it.[ac] Hence, we are led to suspect that some at least of those symptomatic weaknesses, are mistakes in diagnosis. This suspicion will be shared by most persons tolerably acquainted with the present state of psychology, and particularly with the manner in which foregone theories are supported by over-refined analysis. At all events, the reactionary strength of the mind is best shown in the concrete beliefs resulting from its own simplest activities. Our simplest mental activities are naturally our earliest. Amongst them, none are more distinctly marked than our impulses to believe and act upon certain definite pre-suppositions. These differ from the vague and purposeless dreams of childhood, by gradually becoming clear, practical, and expansive. One of the most vigorous, permanent, and prevailing, amongst them all, is our human belief in the existence of supernatural power. Upon another presupposition (not originally the clearest), seems to rest, in the first degree, that principle which gives validity to all the inductive sciences. We will carefully examine this latter belief, with the object of drawing from the process certain aids for an examination of the former.[ad]