Sophistry is a productive art, human, of the imitation kind, copy-making, of the appearance-making kind, uninformed and insincere in the form of contrary-speech-producing art.
Gross sophistry has scarce ever had any influence upon the opinions of mankind, except in matters of philosophy and speculation; and in these it has frequently had the greatest.
Consider Socrates' conclusion about the nature of true or artful speech, which allows an interesting and possibly troubling question to be raised about the relation between philosophy and sophistry.