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.

Blushing is the most peculiar and the most human of all expressions. Monkeys redden from passion, but it would require an overwhelming amount of evidence to make us believe that any animal could blush.

Many kinds of monkeys have a strong taste for tea, coffee and spirituous liqueurs.

In my most extreme fluctuations I have never been an atheist in the sense of denying the existence of a God ... I think that generally (& more and more so as I grow older) but not always, that an agnostic would be the most correct description of my state of mind.

There is no fundamental difference between humans and the higher mammalsin their mental faculties

...one doubts existence of free will [because] every action determined by heredity, constitution, example of others or teaching of others." "This view should teach one profound humility, one deserves no credit for anything...nor ought one to blame others.

In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Light will be thrown on the origin of man and his history.