Now, in what manner have these ingenious arguments been met? Until quite recently, no one has supposed that any light on this subject could be derived from geology. Indeed, even now, by many, that science is regarded as favoring the idea of the world's eternity. Neither has it been thought that, on a question of natural theology, like this, it was proper to appeal to the Bible. Philosophers and divines, however, have attempted to reply to these arguments, irrespective of geology and revelation; and they have generally convinced themselves that they have been successful. But to my mind, I must confess, this has always appeared the weakest spot in natural religion. Some of the arguments to prove the world not eternal do, indeed, appear, at first statement, very profound; but they rather silence than convince; and the longer we reflect upon them, the more apt are we to doubt their force.
And here I am constrained to bear testimony to the masterly manner in which this subject has been treated by Dr. Chalmers. Perceiving that the defences of natural religion on this subject were weak, in spite of much show of strength, he has laid out his giant force of intellect in clearing away the rubbish and building a rampart of rock. His remarkable skill in seizing upon and bringing out prominently the great principles of a difficult subject, and turning them round and round till they fill every eye, is here most happily exerted.
Let us now proceed, in the first place, to examine the arguments that have been adduced to prove the non-eternity of the world, independent of geology and revelation; and in the second place, to derive from these two sources of evidence the true ground on which that proposition rests.
The first supposed proof that the world has not eternally existed is derived from what is called the _a priori_ argument for the existence of the Deity, originally proposed by the monk Anselmus, and afterwards more fully illustrated in England by Dr. Samuel Clarke. Take the following brief summary of this argument, as applied to the eternity of matter, in the words of Dr. Crombie.
"Whatever has existed from eternity, independent and without any external cause, must be self-existent. Whatever is self-existent must exist necessarily, by an absolute necessity in the nature of the thing. This is also self-evident. It follows, therefore, that unless the material world exist necessarily, by an absolute necessity in its own nature, so that it must be a contradiction to suppose it not to exist, it cannot be independent and eternal. In order to disprove this absolute necessity, he [Dr. Clarke] reasoned thus: If matter be supposed to exist necessarily, then in that necessary existence is included the power of gravitation, or it is not. If not, then in a world merely material, and in which no intelligent being presides, there never could have been any motion. But if the power of gravitation be included in the pretended necessary existence of matter, then it follows necessarily, that there must be a vacuum; it follows, likewise, that matter is not a necessary being. For if a vacuum actually be, then it is plainly more than possible for matter not to be."