7. Again; theological students sometimes adopt erroneous principles or unwise methods of reasoning in their search after truth, and do not discover their mistake till they are landed in doubt and unbelief. They find certain principles laid down by men in high repute for science, and adopt them without hesitation, not considering that men of science are sometimes mad, fanatical infidels, and that they manufacture principles without regard to truth, for the simple purpose of undermining men's faith in God and religion. Writers on science of one school tell you, that in your study of nature, you must be careful never to admit the doctrine of final causes; or, in other words, that you must never entertain the idea that anything in nature was meant to answer any particular purpose. You must, say they, if you would be a true philosopher, shut out from your mind all idea of design or contrivance in the works of nature. You must just look at what is, and not ask what it is for. You may find wonderful adaptations of things to each other, all tending to happy results; but you must never suppose that any one ever _designed_ or _planned_ those adaptations, with a _view_ to those happy results. You must confine yourself entirely to what you see, and never admit the thought of a Maker whom you do not see. You must limit your observations to what is done, and not dream of a Doer. You may see things tending to the diffusion of happiness, but must not suppose that there is a great unseen Benefactor, who gives them this blessed tendency. And if you feel in yourself a disposition to gratitude, you must treat it as a foolish, childish fancy, and suppress it as irrational. A sillier or a more contemptible notion--a notion more opposed to true philosophy and common sense,--can hardly be conceived. How any one could ever have the ignorance or the impudence to propound such an unnatural and monstrous absurdity as a great philosophical principle, would be a mystery, if we did not know how infidelity perverts men's understandings, and, while puffing them up with infinite conceit of their own wisdom, transforms them into the most arrant and outrageous fools. Yet this monstrous folly has found its way into books, and papers, and reviews, and, through them, into the minds of some Christian students; and when the madness of the notion is not detected, it destroys their faith, and makes them miserable infidels.