Ronald Bailey reviews Samuel Arbesman's The Half-Life of Facts: Why Everything We Know Has an Expiration Date:
Since scientific knowledge is still growing by a factor of ten every 50 years, it should not be surprising that lots of facts people learned in school and universities have been overturned and are now out of date. But at what rate do former facts disappear? Arbesman applies the concept of half-life, the time required for half the atoms of a given amount of a radioactive substance to disintegrate, to the dissolution of facts.
For example, the half-life of the radioactive isotope strontium-90 is just over 29 years. Applying the concept of half-life to facts, Arbesman cites research that looked into the decay in the truth of clinical knowledge about cirrhosis and hepatitis. “The half-life of truth was 45 years,” reported the researchers.
In other words, half of what physicians thought they knew about liver diseases was wrong or obsolete 45 years later. As interesting and persuasive as this example is, Arbesman’s book would have been strengthened by more instances drawn from the scientific literature.