In his book One Crowded Hour, Tim Bowden writes about a small war in Borneo in 1964. The nations of Indonesia and Malaysia got into a shouting match that turned into a shooting match. Because of treaty relations, a group of Gurkhas from Nepal were sent to aid the Malaysians. Not long after they arrived, they were asked if they would be willing to jump into combat in a surprise attack. Because they were not trained as paratroopers they had the right to refuse.
The Gurkhas usually agreed to do anything they were asked, but this time they said no. The next day, one of their leaders came to the high command and reported that they had met and reconsidered and would make the jump but only under certain conditions. First, the land had to be soft and marshy. The officer replied that the jump was to be in the jungle, so that would not be a problem. Second, the planes would have to fly as slow as possible and not over a hundred feet above the ground. The officer replied that the planes always flew very low, but the hundred feet would be a problem. At that height, the parachutes would not have time to open. When the officer said that, the Gurkha leader smiled and said, “Parachutes? You never said anything about parachutes. Of course, we’ll do it.”
(Borrowed from an article by Delmer Chilton in The Living Lutheran, Aug 2017)
A presupposition is something assumed or taken for granted without empirical verification. Dangerous. Very dangerous simply because the actual fact(s) could be diametrically contrary to what one supposes. To wit, the Gurkha example above. Or thinking someone hates you when not a cell in their body feels that way. Or attempting to cross a rickety, old bridge thinking, that’ll easily hold up my Hummer.
On the old TV show Dragnet, police detective Jack Webb would interview witnesses with the words: Just the facts, mam; just the facts. It’s always good to check, and double-check, what the facts really are. It could save a lot of time, trouble, misunderstanding . . . or even lives.