Indeed the argument which we are considering, seems to us to be founded on an entire mistake. There are branches of knowledge with respect to which the law of the human mind is progress. In mathematics, when once a proposition has been demonstrated, it is never afterwards contested. Every fresh story is as solid a basis for a new superstructure as the original foundation was. Here, therefore, there is a constant addition to the stock of truth. In the inductive sciences again, the law is progress. Every day furnishes new facts, and thus brings theory nearer and nearer to perfection. There is no chance that, either in the purely demonstrative, or in the purely experimental sciences, the world will ever go back or even remain stationary. Nobody ever heard of a reaction against Taylor's theorem, or of a reaction against Harvey's doctrine of the circulation of the blood.
But with theology the case is very different. As respects natural religion,--revelation being for the present altogether left out of the question,--it is not easy to see that a philosopher of the present day is more favourably situated than Thales or Simonides.
He has before him just the same evidences of design in the structure of the universe which the early Greeks had. We say just the same; for the discoveries of modern astronomers and anatomists have really added nothing to the force of that argument which a reflecting mind finds in every beast, bird, insect, fish, leaf, flower and shell. The reasoning by which Socrates, in Xenophon's hearing, confuted the little atheist Aristodemus, is exactly the reasoning of Paley's Natural Theology. Socrates makes precisely the same use of the statues of Polycletus and the pictures of Zeuxis which Paley makes of the watch. As to the other great question, the question, what becomes of man after death, we do not see that a highly educated European, left to his unassisted reason, is more likely to be in the right than a Blackfoot Indian. Not a single one of the many sciences in which we surpass the Blackfoot Indians throws the smallest light on the state of the soul after the animal life is extinct. In truth all the philosophers, ancient and modern, who have attempted, without the help of revelation to prove the immortality of man, from Plato down to Franklin, appear to us to have failed deplorably.
Then, again, all the great enigmas which perplex the natural theologian are the same in all ages. The ingenuity of a people just emerging from barbarism is quite sufficient to propound those enigmas. The genius of Locke or Clarke is quite unable to solve them. It is a mistake to imagine that subtle speculations touching the Divine attributes, the origin of evil, the necessity of human actions, the foundation of moral obligation, imply any high degree of intellectual culture. Such speculations, on the contrary, are in a peculiar manner the delight of intelligent children and of half civilised men. The number of boys is not small who, at fourteen, have thought enough on these questions to be fully entitled to the praise which Voltaire gives to Zadig.
"Il en savait ce qu'on en a su dans tous les ages; c'est-a-dire, fort peu de chose." The book of Job shows that, long before letters and arts were known to Ionia, these vexing questions were debated with no common skill and eloquence, under the tents of the Idumean Emirs; nor has human reason, in the course of three thousand years, discovered any satisfactory solution of the riddles which perplexed Eliphaz and Zophar.
Natural theology, then, is not a progressive science. That knowledge of our origin and of our destiny which we derive from revelation is indeed of very different clearness, and of very different importance. But neither is revealed religion of the nature of a progressive science. All Divine truth is, according to the doctrine of the Protestant Churches, recorded in certain books. It is equally open to all who, in any age, can read those books; nor can all the discoveries of all the philosophers in the world add a single verse to any of those books. It is plain, therefore, that in divinity there cannot be a progress analogous to that which is constantly taking place in pharmacy, geology, and navigation. A Christian of the fifth Century with a Bible is neither better nor worse situated than a Christian of the nineteenth century with a Bible, candour and natural acuteness being, of course, supposed equal. It matters not at all that the compass, printing, gunpowder, steam, gas, vaccination, and a thousand other discoveries and inventions, which were unknown in the fifth century, are familiar to the nineteenth. None of these discoveries and inventions has the smallest bearing on the question whether man is justified by faith alone, or whether the invocation of saints is an orthodox practice. It seems to us, therefore, that we have no security for the future against the prevalence of any theological error that ever has prevailed in time past among Christian men. We are confident that the world will never go back to the solar system of Ptolemy; nor is our confidence in the least shaken by the circumstance, that even so great a man as Bacon rejected the theory of Galileo with scorn; for Bacon had not all the means of arriving at a sound conclusion which are within our reach, and which secure people who would not have been worthy to mend his pens from falling into his mistakes.