What of other lies - lies which did not necessarily make us act to our disadvantage, nor took anything from us, but which just misled us? Why should we be hurt by them?
It is all because of trust, she decided. We trusted others to tell us the truth and were let down by their failure to do so. We were hoodwinked, shown to be credulous, which is all about loss of face. And then she decided that it was nothing to do with trust, or pride. It was something to do with the moral value of things as they really were. Truth was built into the world; it informed the laws of physics; truth was the world. And if we lied about something, we disrupted, destabilized that essential truth; a lie was wrong simply because it was that which was not. A lie was contra naturam. Truth was beauty, beauty truth. But was Keats right about that? If truth and beauty were one and the same thing, then why have two differnet terms to describe it? Ideas expressed in poetry could be beguiling, but philosophically misleading, even vacuous, like the rhetoric of politicans who uttered the most beautiful-sounding platitudes about scraps of dreams, scraps of ideas.
Alexander McCall Smith in full philosophical flight - while wearing Isabel Dalhousie's contact lenses - in chapter 11 of The Comfort of Saturdays.