Many people take facts at face value, but it turns out that half of what we feel we know is truly false, and always has been. In the recently published Half Life of Facts: Why Everything We Know Has an Expiration Date, Samuel Arbesman presents scientific knowledge in a different way than most think of it. Though we all know that science has been wrong before—the danger of us falling off the edge of the earth due to its flatness, for example—most do not consider every fact that has been accumulated to eventually be disproven. This gives science a sort of feeling of futility that many of us are unwilling to accept.

Samuel Arbesman is an expert in scientometrics, or the study of measuring and analyzing science, his main area of study being how facts are made and remade today. In 1965 Derek J Solla found that scientific knowledge is growing at a rate of 4.7 percent annually, with a compound interest rate of about seven percent. This means that every ten to fifteen years the amount of scientific knowledge doubles. A 2009 study found that scientific knowledge is still growing at a rate of about 4.7 percent. While this seems to signal endless increasing progress, Arbesman presents a counteracting force, the “half-life” of knowledge.

The concept of half-life, which usually refers to radioactive atoms, is the time it takes for half of a certain substance to decay. Arbesman applies this to scientific knowledge, describing the amount of time that it takes for facts to be proven wrong—for the “dissolution of knowledge”. Arbesman uses the example of clinical knowledge about cirrhosis and hepatitis, arguing that the half-life of this knowledge, or the amount of time that it took for it to become obsolete, was 45 years.

John Ioannidis, a professor at the Tufts School of Medicine argues in his recent article “Why Most Published Research Findings are False” that many of the “facts” of scientific findings are less facts than they are “accurate measures of the prevailing bias” in that particular field. Furthermore, many people only consider facts that fit into their conception of how the world works. Rather than considering new facts that would require us to change the way we think, we only choose to remember those that work with what we already consider to be true. Thus, many of the things that we consider to be facts have gone through two layers of confirmation bias, first in the scientific field, and then in our personal consideration of them.

Arbesman provides some suggestions for us to combat the constant reformation of knowledge. He first suggests the simple understanding that not everything we accept as a fact is true and knowing that knowledge is constantly changing should keep us vigilant in our search for new knowledge. Following this, he makes the more outlandish claim that we stop memorizing things and instead outsource our individual memories to “the cloud” or the Internet. He argues that everything that we could ever need to know we could look up on the Internet.

Arbesman’s new book is an important reminder that everything that we think we know is not necessarily true. A “fact” is not a permanent fixture that can never be disproven. Science is fallible. In fact, the scientific method is built only to disprove and revise theories. Once a theory is made it is supposed to be replicated and continually tested to stretch its limits in order to determine if and where it holds true. A theory can only be tested and retested to ensure that it is not false. There is no mechanism, however, for proving it conclusively true. Thus, it makes sense that that our knowledge, while it is exponentially growing, is also decaying. The realization that one should not blindly accept facts, and that scientific findings are no the end all be all of truth seems rational. It also inevitably raises the question of if there is, or every will be, anything that we can know for certain.

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Attribution

“Half Of The Facts You Know Are Probably Wrong,” Ronald Bailey, Reason