When twenty-year-old Benjamin Franklin included “sincerity” on his list of Thirteen Virtues, in 1726, he was highlighting a moral trait that had been in place for two centuries. “Use no hurtful deceit,” he wrote, “think innocently and justly, and, if you speak, speak accordingly.”

Franklin’s predecessor Deists harbored demands for personal integrity and upright citizenship, too, leading sincerity to be esteemed by John Locke, the Third Earl of Shaftesbury, and Benjamin Hoadly, an English minister who assured listeners that “the favour of God follows sincerity.” Insincere dissemblers, on the other hand, set in high relief by Denis Diderot in Rameau’s Nephew (1761), were seen as hiding their true identities, disturbing the natural social order, and engaging in dissimulation. Jean-Jacques Rousseau famously celebrated “the plain and noble effusions of an honest soul,” in Letter to M. d’Alembert (1758), noble savages who “speak a language far different from the insincere demonstrations of politeness (and the false appearances) which the customs of the great world demand.” To be sincere in the eighteenth century was a sign of being an upright Christian.

It was not always so. In Latin, the adjective sincerus was used solely to describe the integrity of physical things (glass, wine, or precious stones), derived from the root cerus, meaning “pure, whole, or sound.” It was not until fifteen hundred years later, during the Protestant Reformation, that “sincerity” came to describe a quality of person, specifically a person whose outer expressions matched his or her inward states. As masses of churchgoers began to question the spiritual relevance of bloated Church ritual and pomp, Martin Luther extolled the personal value of sincerity, including the German word for it, Aufrichtigkeit, four times in his Ninety-Five Theses. John Calvin urged adherents to be sincere above all else, because “the principal thing—that which God especially requires—is to bring a sincere heart.” And an English Protestant reformer named John Frith first used the English word “sincerity” in a 1533 religious tract to describe the fourteenth-century heretic John Wycliffe—who translated the Vulgate Bible into English—as “a man of a very sincere life,” a conviction that got Frith burned at the stake.

Sincerity as a human moral trait was something new on the world stage in the sixteenth century, and it did something new to Western personality at the cusp of the modern age: it forged a sense of inwardness and self-reflection, a fresh conception of self-possessed integrity and authentic being. “To thine own self be true,” famously extolled Shakespeare’s Polonius, “and thou canst not be false to any other man.”

If this all sounds wonderful, it’s because it perfectly aligns with our contemporary valorization of authenticity, a quality inherited from these religious origins and from the massive influence of Romanticism on contemporary culture. But it is precisely in Shakespeare’s unifying of sincerity with oneself and sincerity with others that the vast human potential for deception emerges, which is why, despite Franklin’s praise, we are wise to remain skeptical.

Sincerity, after all, is not the same as truthfulness or honesty, traits which refer to the accurate representation of things outside of one’s head. But to express one’s beliefs and feelings sincerely is to represent something to which we alone have access. Being sincere thus says nothing about how accurate, trustworthy, or competent those feelings or beliefs actually are. I may very sincerely believe that Pennsylvania is in Canada, that I have been chosen by angels to live forever, that all triangles are round, or that all children should live in cages. All of these things remain false or undesirable by others regardless of how sincerely I believe them to be true or right. Moreover, there can be no verification of sincerity; there can only be a sense that someone is being sincere or not. And as anyone interested in politics knows, “the secret of success is sincerity,” as George Burns once quipped. “If you can fake that, you’ve got it made.”

Burn’s quip is funny because it’s true, and here’s why: since Ben Franklin’s time, the value of sincerity has marched from religious and aesthetic culture into the vortex of commercial and political life, catalyzed by the beacon to individual authenticity. Today, we’re hard-pressed to find corporate advertising that doesn’t urge buyers to be their sincere and authentic selves though purchasing products that encourage you to “do your own thing,” “blaze your own trail,” or “have it your way.” The private virtue of sincerity has been ransacked by commerce and politics, coloring it with the qualities of a dead, fictional ritual, reserved now for tearful scenes in romantic comedies, Celine Dion lyrics, or the rote letter-closing. “The word has lost most of its high dignity,” wrote Lionel Trilling in 1972, “if we speak it, we are likely to do so with either discomfort or irony.”

We live in a vastly different world than Ben Franklin did. As I see it, this has much to do with his era permitting for the moral and conceptual distinction between public and private selves, a distinction that entailed differing sets of virtues. Franklin’s list—which included temperance, tranquility, cleanliness, and silence—was written for the development of his own personal character. To apply these to public life can easily overshadow qualities more important to civic virtue, and thus distract stakeholders from the fact that public officials are accountable to the admittedly less intimate standards: duty to law, fairness, truthfulness, objectivity, responsibility, and accuracy.

R. Jay Magill, Jr. is the author of Sincerity (W.W. Norton, 2012) and Chic Ironic Bitterness (Univ. of Michigan Press, 2007). He is currently writing a book entitled Against Intimacy.