At one time we had truth and lies. Now we have truth, lies, and statements that may not be true but we consider too benign to call false. Euphemisms abound. We’re “economical with the truth,” we “sweeten it,” or tell “the truth improved.” The term deceive gives way to spin.  At worst we admit to “misspeaking,” or “exercising poor judgment.”  Nor do we want to accuse others of lying.  We say they’re in denial.  A liar is “ethically challenged,” someone for whom “the truth is temporarily unavailable.”
This is post-truth. In the post-truth era, borders blur between truth and lies, honesty and dishonesty, fiction and nonfiction. Deceiving others becomes a challenge, a game, and ultimately a habit. Research suggests that the average American tells lies on a daily basis. These fibs run the gamut from “I like sushi,” to “I love you.”

Ralph keyes
The Post-Truth Era

🔥 Demonstration of the principle of the diesel engine.

The rapid compression of air in a closed volume increases its temperature so much that some substances are able to ignite.

Breathe II