Every flower that gives its fragrance to the wandering air leaves its influence on the soul of man. The wheel and swoop of the winged creatures of the air suggest the flowing lines of subtle art. The roar and murmur of the restless sea, the cataract's solemn chant, the thunder's voice, the happy babble of the brook, the whispering leaves, the thrilling notes of mating birds, the sighing winds, taught man to pour his heart in song and gave a voice to grief and hope, to love and death.
In all that is, in mountain range and billowed plain, in winding stream and desert sand, in cloud and star, in snow and rain, in calm and storm, in night and day, in woods and vales, in all the colors of divided light, in all there is of growth and life, decay and death, in all that flies and floats and swims, in all that moves, in all the forms and qualities of things, man found the seeds and symbols of his thoughts; and all that man has wrought becomes a part of nature's self, forming the lives of those to be. The marbles of the Greeks, like strains of music, suggest the perfect, and teach the melody of life. The great poems, paintings, inventions, theories and philosophies, enlarge and mould the mind of man. All that is is natural. All is naturally produced. Beyond the horizon of the natural man cannot go.
Yet, for many ages, man in all directions has relied upon, and sincerely believed in, the existence of the supernatural. He did not believe in the uniformity of nature; he had no conception of cause and effect, of the indestructibility of force.
In medicine he believed in charms, magic, amulets, and incantations. It never occurred to the savage that diseases were natural.
In chemistry he sought for the elixir of life, for the philosopher's stone, and for some way of changing the baser metals into gold.
In mechanics he searched for perpetual motion, believing that he, by some curious combinations of levers, could produce, could create a force.
In government, he found the source of authority in the will of the supernatural.
For many centuries his only conception of morality was the idea of obedience, not to facts as they exist in nature, but to the supposed command of some being superior to nature. During all these years religion consisted in the praise and worship of the invisible and infinite, of some vast and incomprehensible power, that is to say, of the supernatural.
By experience, by experiment, possibly by accident, man found that some diseases could be cured by natural means; that he could be relieved in many instances of pain by certain kinds of leaves or bark.
This was the beginning. Gradually his confidence increased in the direction of the natural, and began to decrease in charms and amulets, The war was waged for many centuries, but the natural gained the victory. Now we know that all diseases are naturally produced, and that all remedies, all curatives, act in accordance with the facts in nature. Now we know that charms, magic, amulets and incantations are just as useless in the practice of medicine as they would be in solving a problem in mathematics. We now know that there are no supernatural remedies.