Argumentum Ad Populum
A proposition is argued to be true because it is widely held to be true or is held to be true by some important segment of the population. “Because many or most people believe A, A must be true.” We’ll call this consensus gentium the “Appeal to Popularity”. 2) Additionally, the argumentum ad populum has been used more literally as “appeal to the people” or “appeal to the gallery”. In this version, it refers to a direct emotional and rhetorical appeal to the people standing in judgment. For example, when a politician turns to the crowd, looks them in the eye, and begins, “I implore you…”, or, “I know that we all agree that…”, take note. Appeals of this sort may resort to the argument from pity or to the audience’s presumed shared values. Strictly speaking, appealing to “the people” need not be fallacious, but only when the logic (or lack of logic) of the appeal is problematic.
Examples
So irresistible are these evidences of an intelligent and powerful Agent that, of the infinite numbers of men who have existed thro’ all time, they have believed, in the proportion of a million at least to Unit, in the hypothesis of an eternal pre-existence of a creator, rather than in that of a self-existent Universe. Surely this unanimous sentiment renders this more probable than that of the few in the other hypothesis.
Thomas Jefferson, “Letter to John Adams” (1823)
“I think we can all agree that the overwhelming majority of the leadership of the American movement is composed of decent, honest, dedicated people who have made a great contribution involving great personal sacrifice, helping to build a decent American labor movement… We happen to believe that leadership in the American movement is a sacred trust. We happen to believe that this is no place for people who want to use the labor movement to make a fast buck.”
Douglas N. Walton, Informal Logic, p. 91.
A majority of Americans, scientists in particular, now believe that stem cell research is an acceptable and necessary means for the discovery of new therapeutic alternatives. They agree that to reject its use demonstrates an utter lack of compassion for those with currently incurable degenerative diseases. In our time, medieval moral and metaphysical hang-ups should be discarded as the relics of the past that they are. So, stem cell research is morally permissible and should be legalized, indeed generously funded.
The Secret is a New York Times bestseller many times over. Copies are flying off the shelves. Clearly, Rhonda Byrne is on to something. She must be right that the universe really does bend to our needs and desires if we expect the best and banish negative thoughts from our minds.
This move [the Appeal to Popularity] is so outrageous, when baldly stated, that popularity rarely occurs in this blatant formulation. You often have to dig below the surface to find it. For example, M expresses the belief that drugs are harmful and that people shouldn’t rely on them. N counters, ‘Oh, come off it! Nobody believes that nowadays!’ N has not actually said that because nobody believes it, it is false; but that is the clear implication. Or M says that women are inferior to men. N responds, ‘Surely you must be joking; that crazy idea went out with the ’60s! Where have you been hibernating?’ Again, N stops short of the explict statement of the inference that because no one believes it, the view is false. The best way to counter such moves is to ask, point-blank, ‘Hold on, are you saying that because everyone (or no one) believes it, therefore it is true (or false)?’
Johnson & Blair, Logical Self-Defense, 1983, p. 125.
Critique
Identify the proposition and point out that it may be true or false regardless of what people believe. Indeed, constructivist theories notwithstanding, if truth is objective, then it is independent of subjective opinion by definition.
Point out that the majority of people have often been wrong in the past about truths that we now consider undeniable. Examples are legion, including false beliefs from the past about the flatness of the earth or its orbit around the sun. Moreover, the fact that majority opinion about important and contentious ideas changes — from generation to generation, culture to culture — indicates that the truth of a proposition cannot depend on popular opinion. To which majority should we defer?