This essay is an updating of one that was published exactly two decades ago; in the intervening years there has been a revival of interest in positivism as a historical phenomenon in epistemology and philosophy of science (some references to which are given), but there also has been heightened awareness of the various weaknesses of the positivist position. But the main themes of the original essay are still valid--the tendency persists (and may even have grown stronger) for individuals to charge their opponents indiscriminately with being "positivists" without being clear what actually characterizes this position; and there is still a failure to recognize that positivism was a complex "position" some of whose theses can be held by individuals who strongly oppose other theses and thus often do not deserve this label. Indeed, some present-day opponents of positivism do not realize that they share its important anti-realism or instrumentalism.