Do Facts Have A Half-Life?

Half-life of Facts

Having been in the technology industry for the last 25 years, I’ve felt the need to be constantly learning just to stay current. When I was a developer, it was programming languages: FORTRAN, Pascal, C, Smalltalk, C++, Java, Perl, Python, Ruby – I could never quite keep up. Over the last few years, I’ve experienced a similar phenomenon in social media. Almost every day, someone mentions a ‘new’ must-have social tool I haven’t tried.

While staying current has been a challenge, I was comforted by the idea that once I learned something, I could count on it. After all, facts are facts.

Or are they?

Samuel Arbesman, a Harvard mathematician and author of “The Half-life of Facts“, claims knowledge exhibits radioactive decay. While you can’t know which specific fact will be invalidated over time, you can know how long it will take for half the information in a specific discipline to become obsolete.

Arbesman studies scientometrics — literally the science of science. In his words,

Facts change all the time. Smoking has gone from doctor recommended to deadly. We used to think the Earth was the center of the universe and that Pluto was a planet. For decades, we were convinced that the brontosaurus was a real dinosaur. In short, what we know about the world is constantly changing.

In his book, Arbesman provides an example from the study of the liver diseases, hepatitis and cirrhosis. Researchers collected nearly 500 articles from over fifty years and asked a panel of experts to judge which were still factual or disproved based on subsequent findings. When they charted the how long it took each article to become outdated, the resulting graph showed half of the information was disproved in 45 years. Essentially medical knowledge about cirrhosis and hepatitis had a half-life of forty-five years.

If facts have a half-life, half of what you know eventually becomes out of date. But that isn’t a reason to stop trying to keep up. The process of learning makes it easier to learn new things. As Arbesman writes, “the accumulation of knowledge can then lead us to a fuller and more accurate picture of the world around us.”

While knowledge may decay over time, one thing should never change: dedicate yourself to a lifetime of learning.

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4 Responses to Do Facts Have A Half-Life?

  1. Annie Miu Hayward May 18, 2014 at 5:38 pm #

    So true. Centuries ago, science taught us that anything the naked eye couldn’t see didn’t exist. Then bacteria & the germ theory emerged (thank goodness). One of my favorite quotes = “Minds are like parachutes; they only function when open.” Always be teachable 🙂

  2. jeff shuey May 18, 2014 at 8:27 pm #

    great post. this got me thinking about the half-life of ‘the facts’ I learned over the past 30 years in business and tech. many have been improved upon and some have just faded away.

  3. Clark Jones May 21, 2014 at 2:26 pm #

    Interesting article, however, I would challenge that knowledge does not decay, rather it is added thereto. In the example about smoking, the “fact” that smoking was Dr. recommended did not change the fact that smoking was then and is now deadly. The fact we did not know about it then, did not and does not change the fact that Smoking has always been deadly. Doctors recommending it didn’t mean it didn’t cause cancer, it was simply that doctors did not fully understand the impact without additional understanding, in this case, with years of data to better factualize their stand. I see this even with Pluto, regardless what “we” decide to call it, that fact that Pluto still exists in its same state and form is irrefutable. What has changed is our additional knowledge of how to classify a planet per se. Truth and knowledge are everlasting. From my perspective, it is how man classifies a “fact” that is in question, based on additional understanding. Thought provoking post.

  4. Always seeking new knowledge May 23, 2014 at 5:05 pm #

    So, if somebody is of the mindset that they shouldn’t learn anything new, how long before they become irrelevant? Yet those are the ones that that most companies choose to promote.

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