FORE:It is evident that when the parts of a machine are joined together, each piece which has contact on more than one side must have specific dimensions; it is farther evident that as many of the joints in a machine as are to accommodate the exigencies of construction must be without space, that is, they represent continued sections of what should be solid material, if it were possible to construct the parts in that manner. This also demands specific dimensions.The teleology of Aristotle requires a word of explanation, which may appropriately find its place in the present connexion. In speaking of a purpose in Nature, he does not mean that natural productions subserve an end lying outside themselves; as if, to use Goethes illustration, the bark of cork-trees was intended to be made into stoppers for ginger-beer bottles; but that in every perfect thing the parts are interdependent, and exist for the sake of the whole to which they belong. Nor does he, like so many theologians, both ancient and modern, argue from the evidence of design in Nature to the operation of a designing intelligence outside her. Not believing in any creation at all apart from works of art, he could not believe in a creative intelligence other than that of man. He does, indeed, constantly speak of Nature as if she were a personal providence, continually exerting herself for the good of her creatures. But, on looking a little closer, we find that the agency in question is completely unconscious, and may be identified with the constitution of each particular thing, or rather of the type to which it belongs. We have said that Aristotles intellect was essentially descriptive, and we have here another illustration of its characteristic quality.333 The teleology which he parades with so much pomp adds nothing to our knowledge of causes, implies nothing that a positivist need not readily accept. It is a mere study of functions, an analysis of statical relations. Of course, if there were really any philosophers who said that the connexion between teeth and mastication was entirely accidental, the Aristotelian doctrine was a useful protest against such an absurdity; but when we have established a fixed connexion between organ and function, we are bound to explain the association in some more satisfactory manner than by reaffirming it in general terms, which is all that Aristotle ever does. Again, whatever may be the relative justification of teleology as a study of functions in the living body, we have no grounds for interpreting the phenomena of inorganic nature on an analogous principle. Some Greek philosophers were acute enough to perceive the distinction. While admitting that plants and animals showed traces of design, they held that the heavenly bodies arose spontaneously from the movements of a vortex or some such cause;222 just as certain religious savants of our own day reject the Darwinian theory while accepting the nebular hypothesis.223 But to Aristotle the unbroken regularity of the celestial movements, which to us is the best proof of their purely mechanical nature, was, on the contrary, a proof that they were produced and directed by an absolutely reasonable purpose; much more so indeed than terrestrial organisms, marked as these are by occasional deviations and imperfections; and he concludes that each of those movements must be directed towards the attainment of some correspondingly consummate end;224 while, again, in dealing with those precursors of Mr. Darwin, if such they can be called, who argued that the utility of an organ does not disprove its spontaneous origin, since only the creatures which, by a happy accident, came to possess it would survivehe334 answers that the constant reproduction of such organs is enough to vindicate them from being the work of chance;225 thus displaying his inability to distinguish between the two ideas of uniform causation and design.
