Robert A. Heinlein, author of Stranger in a Strange Land

“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, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyse a new problem, pitch manure, program

a computer, cook a tasty meal, fight efficiently, die gallantly. Specialisation is for insects.” 

The 25 Essential Tools of Excellence, here.