Little mind are interested in the extraordinary; great minds in the commonplace
Elbert Hubbard (1856-1915)
 

As long as our brain is a mystery, the universe, the reflection of the structure of the brain, will also be a mystery.
Santiago Ramón y Cajal (1852-1934)

We shoud take care not to make the intellect our god; it has, of course, powerful muscles, but not personality
Alberet Einstein (1879-1955)

All things can corrupt perverted minds
Ovid, Tristia, Bk. II
 

My life and work has been aimed at one goal only: to infer or guess how the mental apparatus is constructed and what forces interplay and counteract in it.
Sigmund Freud

The remarkable thing about the human mind is its range of limitation
Cleia Green
 

Happiness is beneficial for the body, but it is grief that develops the powers of the mind
Marcel Proust (1871-1922)