Showing a greater fondness for their own opinions than for truth, they sought to deny and disprove the new things which, if they had cared to look for themselves, their own senses would have demonstrated to them.

I therefore concluded, and decided unhesitatingly, that there are three stars in the heavens moving about Jupiter, as Venus and Mercury about the Sun; which at length was established as clear as daylight by numerous other observations.

Some, merely to contradict what I had said, did not scruple to cast doubt upon things they had seen with their own eyes again and again.

Where the senses fail us, reason must step in.

It was granted to me alone to discover all the new phenomena in the sky and nothing to anybody else. This is the truth which neither envy nor malice can supress.

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual.

That sculpture is more admirable than painting for the reason that it contains relief and painting does not is completely false. ... Rather, how much more admirable the painting must be considered, if having no relief at all, it appears to have as much as sculpture!