Promoting a product that is not yet pervasively used (or a cause that is not yet widely supported) is a primary purpose of advertising. Tobacco advertisements would be no more misleading for suggesting pervasive use of tobacco products than are any other advertisements that attempt to expand a market for a product, or to rally support for a political movement. Any inference from the advertisements that business would like for tobacco use to be pervasive is entirely reasonable, and advertising that gives rise to that inference is in now way deceptive.
Robin is correct that Arendt understands the political role of the liar. Politics for Arendt is about opinion and some opinions are absolutely essential to our liberal democratic world. For example, the idea that "All men are equal" is one of those lies, those fictions, that Arendt argues is a great achievement of modern politics. Of course not all men are equal in any factual sense. But the political conviction that we are politically equal underlies the possibility of politics. Such is the kind of political lying that Arendt recognizes as important.
As central as Lying may be to politics, certain lies corrode politics. The lies we should worry about, Arendt writes, are those active lies whereby facts are denied and alternative realities are created. When deception, spin, and propaganda become the driving forces of politics, facts retreat behind the need for consistent talking points and coherent narratives. The essence of totalitarian rule is the elimination of those facts and persons whose reality counters the coherent fiction underlying the state. And even in non-totalitarian states, the reduction of facts to simply another opinion corrodes the common sense and shared world that underlies a civil and engaged political sphere. The possibility of politics depends upon the continued availability of commonly accepted facts and pre-political truths that bind a polity together.
In a time of seemingly infinite information, we are experiencing unprecedented doubt about facts. All kinds of "authoritative" claims made by leading public figures turn out to be little more than thin air. Facts, as Arendt saw, are all around us being reduced to opinions; and opinions masquerade as facts. As fact and opinion blur together, the very idea of factual truth falls away. And increasingly the belief in and aspiration for factual truth is being expunged from political argument.
While Arendt understood that lying could be useful and even was the essence of some politics, she also knew that the loss of factual truth in the political realm is an existential threat to politics and also to human life in general. Arendt rejects the classical maxim fiat justitia, et pereat mundus (Let justice be done, even if the world perish); instead she endorses the reformulation: Fiat veritas, et pereat mundus. Let Truth be done, though the world may perish. Her point is simple: We cannot give up on truth-even if it means the end of the world! This is because the loss of truth leads to the loss of the world. Without truth, without the ability to say what is, there is no permanence, no common world. The danger is that when truth disappears, the world wobbles. We lose our bearings. We lose what holds us together-the common sense and common assumptions-that are the furniture and stability of our human world.
Arendt's worry is that when truth is impossible, when truth disappears, when the world wobbles, the result is cynicism. As she writes: "It has frequently been noticed that the surest long-term result of brainwashing is a peculiar kind of cynicism-an absolute refusal to believe in the truth of anything, no matter how well this truth may be established." In other words, the danger from a consistent and total substitution of lies for factual truth is not that the lie will win out-that is highly unlikely. Rather, the danger posed by the demise of factual truth is the victory of cynicism, the belief that it is simply not possible to "say what is." What cynicism means is that the sense of factual truth from which we take our bearings in the real world is wasting away.