Russian author Leo Tolstoy (1828-1910) wrote in the essay “What Is Art?” (1897; English translation 1898):
 
“A friend of mine, speaking of the relation of critics to artists, half jokingly defined it thus: ‘Critics are the stupid who discuss the wise.’ However partial, inexact, and rude this definition may be, it is yet partly true, and is incomparably juster than the definition which considers critics to be men who can explain works of art.”
 
Tolstoy’s friend’s name is not known. “Critics are the stupid who discuss the wise” is a widely cited insult of critics, but it’s generally acknowledged that not all critics are stupid and not all artists are wise.
 
 
Wikipedia: Leo Tolstoy
Count Lev Nikolayevich Tolstoy (Russian: Граф Лев Никола́евич Толсто́й, pronounced [lʲev nʲɪkɐˈlaɪvʲɪtɕ tɐlˈstoj]; known in the Anglosphere as Leo Tolstoy; September 9, 1828 – November 20, 1910) was a Russian writer who primarily wrote novels and short stories. Later in life, he also wrote plays and essays. Tolstoy is equally known for his complicated and paradoxical persona and for his extreme moralistic and ascetic views, which he adopted after a moral crisis and spiritual awakening in the 1870s, after which he also became noted as a moral thinker and social reformer.
 
Wikipedia: What Is Art?
“What Is Art?” (Russian: Что такое искусство? [Chto takoye iskusstvo?]; 1897) is an essay by Leo Tolstoy in which he argues against numerous aesthetic theories which define art in terms of the good, truth, and especially beauty. In Tolstoy’s opinion, art at the time was corrupt and decadent, and artists had been misled.
 
Google Books
What Is Art?
By Leo Tolstoy
Translated from the Russian) by Charles Johnston
Philadelphia, PA: H. Altemus
1898
Pg. 103:
A friend of mine, speaking of the relation of critics to artists, half jokingly defined it thus: “Critics are the stupid who discuss the wise.” However partial, inexact, and rude this definition may be, it is yet partly true, and is incomparably juster than the definition which considers critics to be men who can explain works of art.
 
Google Books
1 July 1900, The Musical Times, “What is Art?,” pg. 446, col. 1:
COUNT TOLSTOY, in answering his self-propounded question, does not forget to decry the critics. (...) But he does not entirely agree with a friend who once said, “Critics are the stupid who discuss the wise.” Indeed, he brands the remark as partial, inexact, and rude. Yet he holds it partly true, and more just than it would be to say that critics are men who can explain works of art. Critics, according to our author, are wholly superfluous persons. If a work of art be good, it explains itself; if it be bad, no amount of explanation can make it contagious. In this summary manner is the whole array of modern criticism dismissed.
 
Google News Archive
11 December 1949, St. Petersburg (FL) Times, “Program Gives Critics A Lambasting” by John Crosby, pg. 41, col. 7:
NBC—they must have a complex on us critics — went on gleefully to quote that wonderful man Anonymous: “Critics, the stupid who discuss the wise.” Well, I was down at Bleeck’s with Anonymous—a pen name for Richard Maney—when he made that crack.
 
Google Books
11 September 1995, Network World, “Back to Reality” by David J. Buerger, pg. 89, col. 1:
“Critics,” as the adage goes, “are the stupid who discuss the wise.”
 
But that’s not always the case. Novell, Inc. is a good example of a successful company besieged by critics. Unlike the adage, though, Novell’s critics have not always been stupid nor the company wise.