So far as hypotheses are concerned, let no one expect anything certain from astronomy, which cannot furnish it, lest he accept as the truth ideas conceived for another purpose, and depart from this study a greater fool than when he entered it.
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.
Pouring forth its seas everywhere, then, the ocean envelops the earth and fills its deeper chasms.
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.