May 19, 2020

Go for a walk? Of course I want to go for a walk. Who cares if its raining?


The great enemy of the truth is very often not the lie, deliberate, contrived and dishonest, but the myth, persistent, persuasive and unrealistic.

-John F. Kennedy


It’s raining. Again. It’s not coming down real hard, but it’s wet enough to soak my socks. I have waterproof walking shoes, but the waterproofness applies only to the soles. There is a fabric top over the toes that allow for my feet to “breathe.” Good thing, because if they didn’t get some airing, I don’t think I could bear to take them off. But it allows the rain to get in and I end up with a squishy gait before too long.

Waldo trots along as if there’s no difference between today and a dry day. The water rolls off his coat, shiny from natural oils, and only very slowly penetrates to his skin. When it does, he does that doggy-shake thing where every square inch of skin waves back and forth like a wash woman shaking out a wet sheet before hanging it out on the clothesline. Now, in my old flabby age, my skin jiggles when I walk, but there is no way I could ever produce the oscillations he does. I don’t understand how it doesn’t give him a headache.

The forecast for this morning was 45% rain. Well, if this is 45% rain, I wonder what the other 55% is. I know, for a fact, that it’s not sunshine, nor snow, nor sleet, nor gloom of night, nor oobleck. It seems just as wet as the 100% rain I’ve been in, but that kind of rain does come down a little harder. But I’ve also driven through a cloudburst where the water was coming down so hard, it was like trying to drive through a waterfall – you couldn’t see the white line in the middle of the road with the windshield wipers going full blast, nor the shoulder of the road. You simply had to stop and wait for the storm to pass. Was that 1,000% rain? 10,000%?

All kidding aside, I really have wondered what it means when the weatherman says, “45% chance of rain.” Does it mean that the weatherman has arthritic joints that tell him it will rain with, um, a 45% likelihood? He makes a guess and he feels 45% sure that it’s right? I know enough about probability and statistics to know that the probability of a certain thing to occur, given that all other alternatives are equally probable, is the number of ways that thing can occur divided by the total number of ways that anything can occur. So, does 45% chance of rain mean that in similar circumstance, it rains 45% of the time? Does it mean that the meteorologist runs a large number of simulations and 45% of them predict that it’ll rain? Does it mean that he runs his simulations and they, on average, show that 45% of the forecast area will experience rain? It turns out, meteorologists use various models, that have taken many decades to design, and measured data to determine the chances that rain will happen somewhere in a large forecast area and determine what percentage of that area will receive any rain at all. They then multiply the two together. So, if there is a 50% chance that it’ll rain somewhere in the forecast area, but only 20% of the entire area will receive rain, then there is a 10% chance of rain. As we all know, it is difficult to predict the weather. Meteorologists are much better at it than they used to be, but still, they can only predict a probability of something happening. There is no certainty.

The same is true of what’s happening in the world today. No one can predict what’s going to happen with the global economy, the number of cases of COVID-19 (the official name of the disease), or the number of deaths that it’ll cause. Our ignorance goes deeper than people are used to. SARS-CoV-2 (the official name of the virus) is new and we really don’t know much about it. The best we can do is make educated guesses based on how similar viruses that we’ve confronted in the past behave. It’s often a “I’m about 45% sure it’ll rain” kind of educated guess. The more accurate statistical guesses like “45% of the forecast area will get rain” will have to wait until scientists have the time to do good, well-designed, controlled studies and discover enough about what’s happening to come up statistical models that will allow them to make a guess like “45% of the forecast area will experience rain.” Until then, we have to treat anecdotal observations as “interesting, but require more rigorous study” and avoid like the plague (no pun intended) the temptation to tout these observations as being strong evidence of this or that. Patience, grasshopper. Patience. And keep in mind that, in the end, we still won’t be able to come up with certainty, just probabilities.

Meanwhile, Waldo and I are out here, in the rain, doing our six miles, getting wet with 100% certainty.


So, are we going or not?

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