I had the intention of becoming a theologian...but now I see how God is, by my endeavors, also glorified in astronomy, for 'the heavens declare the glory of God.'

The heavenly motions... are nothing but a continuous song for several voices, perceived not by the ear but by the intellect, a figured music which sets landmarks in the immeasurable flow of time.

I measured the skies, now the shadows I measure, Sky-bound was the mind, earth-bound the body rests. [Kepler's epitaph]

My aim is to say that the machinery of the heavens is not like a divine animal but like a clock (and anyone who believes a clock has a soul gives the work the honour due to its maker) and that in it almost all the variety of motions is from one very simple magnetic force acting on bodies, as in the clock all motions are from a very simple weight.

Do we ask what profit the little bird hopes for in singing?

So long as the mother, Ignorance, lives, it is not safe for Science the offspring, to divulge the hidden causes of things.

I also ask you my friends not to condemn me entirely to the mill of mathematical calculations, and allow me time for philosophical speculations, my only pleasures.