To excel in any profession, in which but few arrive at mediocrity, is the most decisive mark of what is called genius, or superior talents.
 Adam Smith, The Wealth of Nations (1776). copy citation

add
Author Adam Smith
Source The Wealth of Nations
Topic genius mediocrity
Date 1776
Language English
Reference An Inquiry into the Nature and Causes of the Wealth of Nations
Note
Weblink http://www.gutenberg.org/files/3300/3300-h/3300-h.htm

Context

“First, the desire of the reputation which attends upon superior excellence in any of them; and, secondly, the natural confidence which every man has, more or less, not only in his own abilities, but in his own good fortune.
To excel in any profession, in which but few arrive at mediocrity, is the most decisive mark of what is called genius, or superior talents. The public admiration which attends upon such distinguished abilities makes always a part of their reward; a greater or smaller, in proportion as it is higher or lower in degree. It makes a considerable part of that reward in the profession of physic; a still greater, perhaps, in that of law; in poetry and philosophy it makes almost the whole.
source