The Half-life of Facts

Why Everything We Know Has an Expiration Date

By: Samuel Arbesman

Narrated by: Sean Pratt

New insights from the science of science....

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. But it turns out there’s an order to the state of knowledge, an explanation for how we know what we know.

Samuel Arbesman is an expert in the field of scientometrics - literally the science of science. Knowledge in most fields evolves systematically and predictably, and this evolution unfolds in a fascinating way that can have a powerful impact on our lives. Doctors with a rough idea of when their knowledge is likely to expire can be better equipped to keep up with the latest research. Companies and governments that understand how long new discoveries take to develop can improve decisions about allocating resources. And by tracing how and when language changes, each of us can better bridge generational gaps in slang and dialect. Just as we know that a chunk of uranium can break down in a measurable amount of time - a radioactive half-life - so too any given field’s change in knowledge can be measured concretely.

We can know when facts in aggregate are obsolete, the rate at which new facts are created, and even how facts spread.

Arbesman takes us through a wide variety of fields, including those that change quickly, over the course of a few years, or over the span of centuries. He shows that much of what we know consists of “mesofacts” - facts that change at a middle timescale, often over a single human lifetime. Throughout, he offers intriguing examples about the face of knowledge: what English majors can learn from a statistical analysis of The Canterbury Tales, why it’s so hard to measure a mountain, and why so many parents still tell kids to eat their spinach because it’s rich in iron. The Half-life of Facts is a riveting journey into the counterintuitive fabric of knowledge. It can help us find new ways to measure the world while accepting the limits of how much we can know with certainty.

©2012 Samuel Arbesman (P)2012 Gildan Media LLC

Critic reviews

“How many chromosomes do we have? How high is Mount Everest? Is spinach as good for you as Popeye thought - and what scientific blunder led him to think so in the first place? The Half-life of Facts is fun and fascinating, filled with wide-ranging stories and subtle insights about how facts are born, dance their dance, and die. In today’s world, where knowledge often changes faster than we do, Samuel Arbesman’s new audiobook is essential listening.” (Steven Strogatz, professor of mathematics, Cornell University, and author of The Joy of X)

Ground breaking knowledge

If you could sum up The Half-life of Facts in three words, what would they be?

The acquired perspective gained by understanding the fluid change of knowledge, that is the idea that facts have a life, is intimidating at first. By understanding how information changes the knowledge of facts, we can overcome our feelings of inadequacy when we do not think we know enough about a situation.
Knowledge changes and more importantly, not everyone is comfortable with that constantly changing landscape. This means that the marketplace is constantly changing because we can never have all the answers.
How liberating to know that decisions are made on known facts which are assumed to be true temporally!

I admired the painstakingly presented examples and the perspective of science, medicine and business.
I recommend this book highly.

What did you like best about this story?

The connection of the author to his father the scientist is powerfull.

Misleading title

Is there anything you would change about this book?

I would have liked it to include more incidents and information about how things we take to be facts cease being so. The book was far more about the accretion of new facts and how we can predict that than it was about the retirement of old facts that are no longer considered true. Of the discussion that there was about facts going away, it was more about facts that were not actually proven to be errors...they tended to just become obsolete and irrelevant but still basically true.

Our understanding changes with our set of facts

Easy to follow book on the changing nature of facts and how they help make our current foundation for science. He illustrates his points by many great vignettes such as why even today spinach is falsely believed to contain a lot of iron. That story alone makes the book worth a listen.

it was true, once

Fascinating story of how what is true today will likely not be true tomorrow. Filled with real life examples of how this has been the case in the past and how it can even be predicted in the future.

Author misrepresents what an actual 'fact' is.

What did you like best about The Half-life of Facts? What did you like least?

The overall story was ok and some really interesting insights were made. However, the author frequently conflates facts with our understanding of facts. He doesn't distinguish between temporal facts (like the current tallest building) with absolute facts (atomic properties). Also, his claim that facts change is flat out wrong. Facts don't change - that is what makes them 'facts'. Our understanding of what the facts are about something may alter or change as we learn more about things, but the facts are always the same. Even the temporal ones are constant, only requiring an extra dimension to quantify it.

One example of the misused logic the author uses is the magnetic properties of iron. He states that the magnetic properties changed over time as we became more capable of purifying the iron to measure it magnetic properties. This is wrong. The magnetic properties of iron never changed one bit. Our ability to measure the properties changed. The fact remained constant, our understanding of the fact improved.

While it seems that the author may actually understand these nuances, as some of the points he makes are very good and require this basic understanding; that he does not articulate this key difference can leave other readers with the wrong impression of what a fact is. This is what causes confusion when the general public argues against scientific knowledge (e.g. climate change or evolution) trying to claim that science is always wrong and our facts keep changing. By not distinguishing the difference, the author is reinforcing this perception.

Think!!!

That is the takeaway message from this book. What we think we know might be more opinion than fact. Try to think critically about EVERYTHING. Facts change. Keep up. Open your mind.

The voice changes are annoying

Sean Pratt's performance and voice are great but there are many abrupt changes in narration as if new material has been injected and has been edited very poorly.

The Changing World of Facts & Analytics

Great book. Highly recommended. Thoroughly enjoyed reading the various examples presented by the Author on how facts change through history.
Nothing is constant and what we consider true today will be supplanted tomorrow. I also enjoyed the journey through data analytics and how new discoveries can be found in data sets in ways not anticipated.

Ok

I just listened to a 10 year old book about how facts are constantly changing

Not quite what I'd hoped

I heard about this book from Annie Duke's excellent "Thinking in Bets" and hoped it would be something along the lines of the practical philosophy of knowledge (what is the meaning of "knowing things" when the "facts" we know actually have half-lives and will often decay). Instead, the book felt heavily focused on facts about numeric data related to technology and measurements, and those are the kinds of facts I'm least interested in. I'd expect the facts "My wallet is in the bedroom" and "when hydrogen and oxygen are heated enough, they combine to form water" to be very different kinds of facts. The first one is an utter banality -- that it becomes "false" at some point is trivial and uninteresting since I expect my wallet to move around from time to time. It would probably be interesting if "My wallet was in the bedroom at 12:35 on October 29, 2022" were false since that would indicate a belief that was false even at the time it happened, but I felt like the book mostly cared about looking at the rate of decay of the clearly-temporal kind of fact, and that kind of fact decay isn't particularly interesting to me. The number of transistors we are currently capable of putting on microchips (Moore's Law) feels more like a "wallet" fact than an "invariant truth" fact, and the book focuses heavily on Moore's Law and similar trends.

I feel like the other kind of fact is a distinct category because I don't expect it to change. When it does change, it forces me to reexamine my beliefs in a way that the fact about my wallet's current location changing doesn't. There are a few interesting discussions along these lines in the book -- especially the magnetic permeability of iron. But, it doesn't seem like this is recognized as a different category, nor does the surprising idea that this is *not* a separate category seem to be discussed.