Mathematics seems to endow one with something like a new sense.

It is always advisable to perceive clearly our ignorance.

It strikes me that all our knowledge about the structure of our Earth is very much like what an old hen would know of the hundred-acre field in a corner of which she is scratching.

The love for all living creatures is the most noble attribute of man.

If a person asked my advice, before undertaking a long voyage, my answer would depend upon his possessing a decided taste for some branch of knowledge, which could by this means be advanced. No doubt it is a high satisfaction to behold various countries and the many races of mankind, but the pleasures gained at the time do not counterbalance the evils.

The question of whether there exists a Creator and Ruler of the Universe has been answered in the affirmative by some of the highest intellects that have ever existed.

From my early youth I have had the strongest desire to understand or explain whatever I observed. ... To group all facts under some general laws.