The Age of Reason/Part I/Chapter XV
It is an idea I have never lost sight of, that all our knowledge of science is derived from the revolutions (exhibited to our eye and from thence to our understanding) which those several planets or worlds of which our system is composed make in their circuit round the Sun.
Had then the quantity of matter which these six worlds contain been blended into one solitary globe, the consequence to us would have been, that either no revolutionary motion would have existed, or not a sufficiency of it to give us the ideas and the knowledge of science we now have; and it is from the sciences that all the mechanical arts that contribute so much to our earthly felicity and comfort are derived.
As therefore the Creator made nothing in vain, so also must it be believed that he organized the structure of the universe in the most advantageous manner for the benefit of man; and as we see, and from experience feel, the benefits we derive from the structure of the universe, formed as it is, which benefits we should not have had the opportunity of enjoying if the structure, so far as relates to our system, had been a solitary globe, we can discover at least one reason why a plurality of worlds has been made, and that reason calls forth the devotional gratitude of man, as well as his admiration.
But it is not to us, the inhabitants of this globe, only, that the benefits arising from a plurality of worlds are limited. The inhabitants of each of the worlds of which our system is composed, enjoy the same opportunities of knowledge as we do. They behold the revolutionary motions of our earth, as we behold theirs. All the planets revolve in sight of each other; and, therefore, the same universal school of science presents itself to all.
Neither does the knowledge stop here. The system of worlds next to us exhibits, in its revolutions, the same principles and school of science, to the inhabitants of their system, as our system does to us, and in like manner throughout the immensity of space.
Our ideas, not only of the almightiness of the Creator, but of his wisdom and his beneficence, become enlarged in proportion as we contemplate the extent and the structure of the universe. The solitary idea of a solitary world, rolling or at rest in the immense ocean of space, gives place to the cheerful idea of a society of worlds, so happily contrived as to administer, even by their motion, instruction to man. We see our own earth filled with abundance; but we forget to consider how much of that abundance is owing to the scientific knowledge the vast machinery of the universe has unfolded.