We ought, however, to keep always in view that, although parallel in some points, there is a wide difference between a machine executed by human hands and the mechanism of the natural world. In the one case, the machine may work independently of the contriver; in the other, the working of the machine is just the mode of the Divine operation.
We have, in the mechanism of the human body, a principle somewhat similar to the self-adjustment of the solar system. The body has been well styled a "self-mending machine." It is constantly subject to disturbances of its normal state by disease and accident, but it possesses a wonderful power of readjusting the disturbed functions, so that the stability of the system, or, in other words, life is preserved. We regard this self-regulating power as one of the strongest evidences of intelligence; and in the same light ought we to view the self-adjustment of the celestial machine.
The solar system is subject to incessant disturbance, but it is so adjusted that the irregularities never endanger its stability. When a rod is poised on the point of the finger, it oscillates from one side to the other, and the stability depends on the oscillations never going beyond a certain degree. In like manner, the orbits of the planets are subject to oscillations, but the stability of the system is insured by these oscillations being subject to a limit. The perturbations to which the orbits of planets are subject may be divided, in regard to