“It's not a lie if you believe it.” — George Costanza in Seinfeld
There are three categories of deception: lying, spinning, and concealment.
Lying, as emphasized, is usually considered deplorable behavior, whereas most people seem to believe that it is acceptable to spin and conceal, even though these behaviors are designed to deceive.
One possible reason for this is because it is thought that lying is more difficult to detect.
What is deception?
where an individual purposely takes steps that are designed to prevent others from knowing the full truth — as that individual understands it — about a particular matter. The deliberate aim, in other words, is not to provide a straightforward or comprehensive description of events.
Deception includes lying, spinning, and concealment.
What is lying?
Lying is when a person makes a statement that he knows or suspects to be false in the hope that others will think it is true. A lie is a positive action designed to deceive the target audience. Lying can involve making up facts that one knows to be false or denying facts that one knows to be true. But lying is not only about the truthfulness of particular facts. It can also involve the disingenuous arrangement of facts to tell a fictitious story. Specifically, a person is lying when he uses facts—even true facts—to imply that something is true when he knows that it is not true.
Spinning is different from lying.
Spinning is when a person telling a story emphasizes certain facts and links them together in ways that play to his advantage, while, at the same time, downplaying or ignoring inconvenient facts. Spinning is all about interpreting the known facts in a way that allows the spinner to tell a favorable story. It is all about emphasizing and deemphasizing particular facts to portray one’s position in a positive light.
The third kind of deception is concealment.
…which involves withholding information that might undermine or weaken one’s position. In cases of this sort, the individual simply remains silent about the evidence, because he wants to hide it from others. Of course, if he is asked a question about the matter and lies to conceal it, that behavior fits my definition of lying.
— Via Why Leaders Lie: The Truth About Lying in International Politics