Seeing is in some respect an art, which must be learnt.

I have looked farther into space than ever a human being did before me.

The phenomena of nature, especially those that fall under the inspection of the astronomer, are to be viewed, not only with the usual attention to facts as they occur, but with the eye of reason and experience.

... finding that in [the Moon] there is a provision of light and heat; also in appearance, a soil proper for habitation fully as good as ours, if not perhaps better who can say that it is not extremely probable, nay beyond doubt, that there must be inhabitants on the Moon of some kind or other?

Since stars appear to be suns, and suns, according to the common opinion, are bodies that serve to enlighten, warm, and sustain a system of planets, we may have an idea of the numberless globes that serve for the habitaton of living creatures.

Seeing is in some respect an art, which must be learnt.

We see it [the as-yet unseen, probable new planet, Neptune] as Columbus saw America from the coast of Spain. Its movements have been felt, trembling along the far-reaching line of our analysis with a certainty hardly inferior to that of ocular demonstration.