Pouring forth its seas everywhere, then, the ocean envelops the earth and fills its deeper chasms.
In so many and such important ways, then, do the planets bear witness to the earth's mobility.
Therefore, having obtained the opportunity from these sources, I too began to consider the mobility of the earth.
Mathematics is written for mathematicians.
I am aware that a philosopher's ideas are not subject to the judgment of ordinary persons, because it is his endeavour to seek the truth in all things, to the extent permitted to human reason by God.
Not a few other very eminent and scholarly men made the same request, urging that I should no longer through fear refuse to give out my work for the common benefit of students of Mathematics.