Wednesday, April 15, 2015

Prediction and science

Some people contend that successful prediction of the hallmark of science. "If economics is a science, why is it so bad at prediction?" they ask.

But they fail to notice how little of the real world physics can predict. I was sitting in my diner this morning as I was composing this, with the jukebox playing and people talking. I thought of what parts of the world around me a physicist could predict with any decent degree of accuracy:

What sound waves will reach my ear in one minute? Not a chance.

Where will my oldest son be in fours hours? Hell, I can't predict that!

When will a complex assemblage of proteins, fats, and carbohydrates arrive in the space in front of me? Sometime in the next ten minutes: a physicist would do worse than anyone who is a regular at the diner.

At what times during the Spurs-Pelicans game tonight will the basketball pass through the net? No.

Where will the maple seed falling off the tree on the street outside land? Well, within a few hundred feet, maybe.

What will be the first star visible in the (partly cloudy) sky this evening? No.

On the stove, one of the chefs was boiling some water. About the only thing of interest going on around me that a physicist could have predicted was how long it would take the water to boil. And that is because the water has deliberately been put in a constrained, artificial set up, in the limited space of a uniformly conductive pot and over the steady heat of a carefully designed flame, precisely to make its time to boiling predictable... much like the way physicists set up an experimental environment.

Scientific prediction is not about the real world as a whole: it is about a world of pure quantity abstracted from the real world.


  1. Yes!

    Also, scientists have been lucky in that there are many readily abstracted systems for them to happen upon. Example -- the planets of the solar system & sun are separated by orders of magnitude of mass and distance, (the sun doesn't actually sit in fixed position, the orbits aren't actually eliptical, but close enough...). Economists don't generally have that going for them. Also, some subjects, or at least, little 'realms' of subjects are overall just easier to abstract intrinsically. I'm convinced that's why physics & certain others (organic chemistry, population genetics, & a few others I can think of) are so 'advanced' compared to even their close relatives (inorganic chemistry, biology, meteorology) -- becasue they're just easier!

    (Careful with this train of thought, though, Gene! You might start applying to climate change....)

    1. Scott, the solar system is an excellent example!

      Climate change: There certainly is a much higher than 0% chance climate scientists are wrong on AGW! I just think they are the one's most likely to be *right* about it.



"If your approach to mathematics is mechanical not mystical, you're not going to go anywhere." -- Nassim Nicholas Taleb