[16] Even at two leagues it is no longer discernible.
You represent the earth in a very contemptible light, said the Marchioness. Nevertheless on this silk-worm's shell we find stupendous works, furious wars, and universal agitation. Yes, answered I, and while all this is going on, nature, who does not concern herself about such frivolous things, carries us all along, with an uninterrupted motion, and amuses herself with the little ball.
It appears very ridiculous, replied she, to give way to so much anxiety, whilst one is living on a thing that is perpetually turning; but unfortunately we are not assured that it does turn, for, to tell you the truth, all the precautions you take to convince me that we should not feel its motion are unsatisfactory. How could it avoid giving some indication by which we should be sensible of it?[17] The most common and natural motions, said I, are the least felt: this observation is true even in a moral sense: the motions of self-love are so frequent in our minds, that for the most part we are not sensible of them, but believe ourselves actuated by other principles. Ah! you are beginning to moralize, said she; moralizing and explaining natural philosophy are a little different; I fancy you grow tired of your subject: let us return home, we have had enough for the first lecture. To-morrow we will come here again—you with your systems, and I with my ignorance.
[17] There are several; one of them is the aberration of the stars. Astron. Book xvii.
In our way to the house, to give her a complete history of systems, I told her that a third had been invented by Ticho Brahe, who, from a determination to keep the earth in a state of rest, placed her in the centre of the universe, making the sun revolve round her, and the planets round the sun; for in consequence of some discoveries which had been lately made, he found it impossible to make the planets go round the earth. The Marchioness, with her usual discernment, concluded that it was mere whim to exempt the earth from moving round the sun, when so many other larger bodies were allowed to perform the revolution; that the sun was rendered more unfit for turning round the earth when incumbered with the other planets, and in short that this system was only calculated to support a prejudice in favour of the earth's immobility,[18] without offering any thing to convince the judgment; we therefore resolved to retain that of Copernicus, which is more uniform and pleasing, and at the same time unmixed with prejudice. In fact its simplicity convinces, whilst its boldness excites admiration.
[18] The ridiculous system of Ticho was invented out of respect to the holy scriptures, not considering that their object was more important than the refutation of popular errors on natural philosophy.
SECOND EVENING.
THE MOON IS A HABITABLE GLOBE.