Half Life of Facts

I’ve always been happy that we engineers don’t have to get additional degrees beyond the B.E. or B.Tech., and that we don’t need to recertify ourselves periodically. 4 years of college and we are done. At the same time, I’ve felt sorry for doctors who (at least in the West) need to get themselves recertified periodically. My mom felt everyone does update themselves, even if it’s not always via a new degree. Surely, she said, all professionals read up new stuff and stay upto date, especially when their job demands it. Don’t engineers learn new programming languages and ways to speed up constructions, she asked?

I think I found the answer when I read this Farnam Street analysis about the book, “The Half-life of Facts: Why Everything We Know Has an Expiration Date”, by Samuel Arbesman. Here’s the theme of that book:

“Knowledge is like radioactivity. If you look at a single atom of uranium, whether it’s going to decay — breaking down and unleashing its energy — is highly unpredictable. It might decay in the next second, or you might have to sit and stare at it for thousands, or perhaps even millions, of years before it breaks apart. But when you take a chunk of uranium, itself made up of trillions upon trillions of atoms, suddenly the unpredictable becomes predictable. We know how uranium atoms work in the aggregate. As a group of atoms, uranium is highly regular.

It turns out that facts, when viewed as a large body of knowledge, are just as predictable. Facts, in the aggregate, have half-lives: We can measure the amount of time for half of a subject’s knowledge to be overturned.”

If that’s true, why is it so? Aren't theories supposed to have been tested? Robert Prisig (of Zen and the Art of Motorcycle Maintenance fame) explains why that's not entirely true…or even possible:

“The purpose of scientific method is to select a single truth from among many hypothetical truths....If all hypotheses cannot be tested, then the result of any experiment are inconclusive and the entire scientific method falls short of its goal of establishing proven knowledge.”

The key phrase there is “If all hypotheses cannot be tested”. They can’t. It would take too much time and money. So we stop testing the others when a hypothesis seems to work. Until we find that the accepted hypothesis fails!

At this point, I know there will be some who will gleefully come to the conclusion that science is imperfect, and hence any form of rubbish can be accepted as truth. Not so fast. As Isaac Asimov said:

“When people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together.”

And now we come to why many professions, like engineering, that don’t force going back for recertification could be dangerous. To put it simply, most of us are stubborn. Unwilling to change our minds. Unable to set aside our preferences. As Richard Zeckhauser said:

“A prevailing theory or paradigm is not overthrown by the accumulation of contrary evidence.”

And as Max Planck put it even more strongly:

“A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”

Unlike many other professions, the medical community doesn’t want to wait for the old to die out before newer ideas get accepted. Which is why they force periodic recertification. And exams.

And no, the half life of facts isn’t a phenomenon restricted to just professions. It holds for all forms of knowledge, so we would all do well to look up Wikipedia more often.