From Human Action — surrounding passage

For primitive man hard fists and pugnacity were as useful as the ability to be clever at arithmetic and to spell correctly are for modern man. It is quite arbitrary and certainly contrary to any biological standard to call only those characteristics which were useful to primitive man natural and adequate to human nature and to condemn the talents and skills badly needed by civilized man as marks of degeneration and biological deterioration.

“To advise man to return to the physical and intellectual features of his prehistoric ancestors is no more reasonable than to ask him to renounce his upright gait and to grow a tail again.”

It is noteworthy that the men who were foremost in extolling the eminence of the savage impulses of our barbarian forefathers were so frail that their bodies would not have come up to the requirements of “dangerous living.” Nietzsche even before his mental breakdown was so sickly that the only climate he could stand was that of the Engadin valley and of some Italian districts.