Assumptions

Me and my buddy B had some discussion at work t'other day about the weight-per-square-foot of steel plates.

10.21 lbs per square foot, for quarter-inch thick plate.

In our work, we need to know weights of things, because we make assemblies that are supposed to float when they go into the water.

Anyway, next morning I was looking at his fabrication drawings for that job. Found a big aluminum plate on a couple drawings. Figured those were old, and the plate spec got changed to steel, but I couldn't find a drawing for the steel plate.

So when B came in, I asked: That 10.2 number we were talking about, that was for a steel plate, right?

He knew right away where I was going.

"I never even thought about it," he said. "I just grabbed the steel book..."


He did half a day's work, making adjustments for the weight of the plate, based on a wrong number, assuming it was the right number. Didn't catch it 'til I asked about it.

Now, suppose he was an economist, not a draftsman. And suppose he was working back in the 1970s when stagflation arose and the economy started going south. And instead of figuring the weight, suppose he was figuring out why the economy was going south and what could be done about it. And suppose instead of half a day, it was half a century before anybody pointed out the mistake.

By then, of course, it wouldn't be just one mistake. By then there would be a whole system in place, built on flawed assumptions. Faulty explanations would be embedded in the minds of economists all over the globe. It would be difficult to get the thing corrected, even when it was obvious the economy was sinking.


BTW, an aluminum plate of the same size weighs about one-third as much as a steel plate -- based on the one plate we were looking at.