The rejoinder has been made that at all events a Will is implied in Design;—and that he who wills acts arbitrarily. Of course, there is a certain sense in which this may be true. A Sovereign will could at pleasure refuse the Right and choose the Wrong, but then it would cease to be a Sovereign Reason. That is, it would cease to be Sovereign at all, in any true Theology. And we may, likewise, add that the ordinary instances and illustrations of Design never aim at proving Will directly;—their immediate object is to shew Intelligence, foreseeing ends or functions, and purposing their attainment. It is clear that Will must indirectly be implied in such an argument. But, then, it is so implied, partly because all Reason is per se identical with Will, and partly because (as we shall endeavour to shew), Causation necessarily emanates from Will. The reader must, however, assign each conclusion to its proper argument, and keep each argument to its proper conclusion;—a rule which those who dispute for victory, and not for truth, frequently fail to observe.
The use we are now making of fitness and adaptation is less to prove the existence of Mind in the Universe, than its grandeur, grasp, and comprehensiveness. For this purpose our clearest evidence arises from the coincidence of several diverse conditions, tending to one sovereign finality of function. And indeed, this argument from coincidence, is generally the most convincing;—the greater the convergence of separate conditions,—the stronger is our assurance that Mind determined the result.[bc] Our sense of sight has always been a favourite subject in Natural Theology. It is familiar, and, so far as a broad outline of the function is concerned, may be easily studied by any common-sense person. It is, also, evidently one Function; yet, even cursory observation shews a great diversity of powers contributing to produce it. How diverse they are, may be perceived by supposing first one and then another element of eyesight to be absent, and considering what the effect of each deficiency must be.
Suppose, there were no light. The eye then, however beautiful and perfect in structure, would not be a means serving any purpose of perception. It is clear thus that the eye is an optical instrument.
Suppose, again, light and optical arrangement both in existence, but, also, that the eye had no power of adjusting itself to the direction of objects and other circumstances; evidently its function of vision would be very much restricted.
In relation to this end, the eye is a mechanical[202] instrument.
We might, further, suppose the optical apparatus to work well, its adjustment also to be perfect,—and the picture on the retina no less so. But, with this perfect picture, suppose all ended. The function of eyesight would be as irretrievably gone as in our first case.
This shews us that the eye does not really see. It is the servant of an impressible Power,—and this impressible power uses it, and sees through it.
Suppose, finally, that the picture on the retina set vibratory nerves in movement—each microscopic stroke producing its effect of vibration. Let something be seen by the impressible Power, but not apprehended as an object of common perception. Let there be no comparison with other sensations; no transcript into sense-language, of what is at once seen, touched, heard, smelled, or tasted. Consider, how barren and unproductive the result! Eyesight is reduced to a play of coloured images. There can be no malleable material for Intelligence to work up. Nothing to be cast into any universal mould;—no possibility of a greedy Mind feeding eagerly through the quick perceiving eye.
In the absence of information given, or thought stimulated, we must pronounce such sight unintelligent;—and the Eye an unintelligible phenomenon. But why? The anatomical structure remains perfect. It is the adaptation that has been lost along with the finality, and this loss is fatal. Hence the paramount importance of finality.