The inquiry we propose will have a great collateral advantage, both to him who doubts and to him who accepts Theism. For we shall at least get rid of what may fairly be termed a stupid prejudice. Persons who read and think little, are apt to base upon their own ignorance a vague presumption that the path of knowledge is plain and easy, until men try to know God. _Then_ all is hard; the pleasant path becomes a rough and toilsome road. Others who read, but think less than they read, are aware that very real obstacles beset all deep inquiry, yet form hazy and imperfect notions as to the true extent of those obstacles. They little think how often we are all obliged to accept and maintain first truths;--difficulties objective, and difficulties subjective, notwithstanding. Of one practical conclusion resulting from these difficulties, we may feel assured beforehand. Many objects of the greatest interest and importance to truth can never be truly known as they are in themselves;--our utmost hope is to know, not them, but as much as we can discover respecting them. And sometimes this limited knowledge is invaluable. If it does not gratify our natural desire for speculation, it may often guide and govern our lives. Unspeakably important, for example, in itself and in its consequences, must be an affirmative answer to our anxious question concerning the existence of a God. * * * * * COROLLARY.--It plainly appears from what has been said, that the knowledge of an "efficient cause" (in physics) does not, and cannot, at all preclude the inquiry after a purpose or "final cause"; but, on the contrary, leads to its investigation. In a watch's action, the former is represented by the moving power--that is, the spring; the latter, by the watch's function--that of indicating hours, minutes, and seconds. Would any uninformed person, examining a watch for the first time, and knowing no more than what he sees,--be able to give to himself any real account of the watch, if spring, train of wheel-work, and pointers, were shown him; but _no_ hint given of the purpose and object of the _whole_ construction? Now, to tell him this, would be to convey the _idea_,--a principle which resides in Mind, and in Mind alone;--and, so residing, leads to intelligent adaptation;--that is, a law or laws apprehended by the active exercise of certain mental faculties. Let the intelligent reader ask himself whether _any_ functional structure can be comprehended on _any_ lower terms?--As however this latter question will be fully discussed further on, it is unnecessary to say more respecting it at present. ADDITIONAL NOTES AND ILLUSTRATIONS TO CHAPTER II. A.--ON THE ABSTRACT REASONINGS INVOLVED IN NATURAL THEOLOGY.