I am actually weary of telling people that I do not pretend to adduce [direct] evidence of one species changing into another, but I believe that this view is in the main correct, because so many phenomena can thus be grouped end explained.

The most energetic workers I have encountered in my world travels are the vegetarian miners of Chile.

...I believe there exists, & I feel within me, an instinct for the truth, or knowledge or discovery, of something of the same nature as the instinct of virtue, & that our having such an instinct is reason enough for scientific researches without any practical results ever ensuing from them.

History shows that the human mind, fed by constant accessions of knowledge, periodically grows too large for its theoretical coverings, and bursts them asunder to appear in new habiliments, as the feeding and growing grub, at intervals, casts its too narrow skin and assumes another.

At no time am I a quick thinker or writer: whatever I have done in science has solely been by long pondering, patience and industry.

I worked on true Baconian principles, and without any theory collected facts.

What wretched doings come from the ardor of fame; the love of truth alone would never make one man attack another bitterly.