When a critic examines the work of any of the great masters in poetry or painting, he may sometimes examine it by an idea of perfection, in his own mind, which neither that nor any other human work will ever come up to
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“Whatever goes beyond this degree, how far soever it may be removed from absolute perfection, seems to deserve applause; and whatever falls short of it, to deserve blame. It is in the same manner that we judge of the productions of all the arts which address themselves to the imagination. When a critic examines the work of any of the great masters in poetry or painting, he may sometimes examine it by an idea of perfection, in his own mind, which neither that nor any other human work will ever come up to; and as long as he compares it with this standard, he can see nothing in it but faults and imperfections. But when he comes to consider the rank which it ought to hold among other works of the same kind, he necessarily compares it with a very different standard, the common degree of excellence which is usually attained in this particular art;” source