But when we carry our survey into other parts, whether of the natural or moral system, we cannot discover any design at all. We frequently perceive structures the use of which we know nothing about; parts of the animal frame that apparently have no functions to perform--nay, that are the source of pain without yielding any perceptible advantage; arrangements and movements of bodies which are of one particular kind, and yet we are quite at a loss to discern any reason why they might not have been of many other descriptions; operations of nature that seem to serve no purpose whatever; and other operations and other arrangements, chosen equally without any beneficial view, and yet which often give rise to much apparent confusion and mischief. Now, the question is, _first_, whether in any one of these cases of arrangement and structures with no visible object at all, we can for a moment suppose that there really is no object answered, or only conceive that we have been unable to discover it? _Secondly_, whether in the cases where mischief sometimes is perceived, and no other purpose appears to be effected, we do not almost as uniformly lay the blame on our own ignorance, and conclude, not that the arrangement was made without any design, and that mischief arises without any contriver, but that if we knew the whole case we should find a design and contrivance, and also that the apparent mischief would sink into the general good? It is not necessary to admit, for our present purpose, this latter proposition, though it brings us closer to the matter in hand; it is sufficient for the present to admit, what no one doubts, that when a part of the body, for instance, is discovered, to which, like the spleen, we cannot assign any function in the animal system, we never think of concluding that it is made for no use, but only that we have as yet not been able to discover its use.