From Robert Heinlein, Time Enough For Love: 

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, confort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly.  Specialization is for insects.

Quoted in Iain McGilchrist, The Matter With Things, Ch. 13, p. 501.