Fermi/Channel Markers (3): What's the point?

Nothing in particular, except for trying to get a sense of scale. One of the hard things is to set a scale, some idea of an outside measure. That's why the National Institute of Standards (and Technology now) exists (in the U.S., there are other national agencies and international agencies all coordinating to do the same thing), to say "here's a pound" or "here's a foot" or gallon or whatever.

A kilogram is famously a piece of metal sitting in a safe in France. A meter, similarly, though they're moving to define meters in other ways that are independent of what happens to the reference.

Gold here isn't magic. It's just that prior to Nixon, the dollar was defined by statute (20 dollars to the ounce of gold before FDR, 35 thereafter) so that's the most convenient method in this case. Plus, while gold has its industrial uses, it's remained otherwise primarily a jewelry or collector's metal since the move to free floating currencies.

That explains the reasoning for the measures, and trust me, they're crude. Economists will argue endlessly about how different ways of measuring these things are better. My purpose here though is to just do my best to provide a definition that's not circular, and that's a useful rule of thumb, nothing more.

(Circular? The meaning of a dollar is a step function in time; a definition of inflation, no matter what it is, has to be calibrated against some manner of independent control, otherwise there's no way generally to verify the measuring stick. Just like in a lab you use external standards to calibrate your test methods before you use them.)

But that's just the nuts and bolts of it, why do it at all?

Things like the "hey kid, here's a nickle?", the little markers in older fiction works that the original authors didn't have to think about. If I give my daughter five bucks for something these days, I know she'll either have to buy an e-book with it, or wait until she's got another five bucks to buy a paper book, it having been since I was a kid since even mass market paperbacks were under 5 bucks per copy.

So if I write a story set just after WWII, say, and I'm thinking about how the kids then lived, if their dad's driving a used, pre-war chevy that he's keeping going with spit and bailing wire, that tells me one thing. If he's moving the family to the suburbs and buying a new Bel-Air a few years later, that tells me something else.

Or maybe I'm writing a story set a hundred years in the future, and the kids then are getting a couple bucks for re-organizing an old hard drive so the new computers can read it. What does that tell me? Maybe the dollar's been re-done again, with new meaning and new values. Why? What would have happened between now and then, and how would it have rippled through to the broader world?