Opportunity makes a thief.

Observation and experiment for gathering material, induction and deduction for elaborating it: these are are only good intellectual tools.

And as for Mixed Mathematics, I may only make this prediction, that there cannot fail to be more kinds of them, as nature grows further disclosed.

He that hath a wife and children hath given hostages to fortune.

It cannot be denied that outward accidents conduce much to fortune, favor, opportunity, death of others, occasion fitting virtue; but chiefly, the mold of a man's fortune is in his own hands

The universe must not be narrowed down to the limit of our understanding, but our understanding must be stretched and enlarged to take in the image of the universe as it is discovered.

I like, you may say, the glitter and colour that comes from the mouth, and I've always hoped in a sense to be able to paint the mouth like Monet painted a sunset.