The essay's core claim and representation were by the late 1980s widely deployed in mainstream economics, even if methodological judgments, like other regulative judgments, are not purely positive. Its critics however, had by then long pointed out the flaw in Friedman's reasoning: by shielding assumptions from the requirement of realism, Friedman admits falsehoods as part of his theory.
He defends against this by requiring only certain phenomena of interest to be explained, but as Samuelson pointed out, this can lead to unscientific cherry-picking of results. Samuelson dubbed Friedman's principle the F-Twist, avoiding naming it after Friedman directly out of courtesy.