Thread by @ReformedTrader

1/ The Half-Life of Facts: Why Everything We Know Has an Expiration Date (Samuel Arbesman)

"Facts, in the aggregate, have half-lives: We can measure the amount of time for half of a subject’s knowledge to be overturned." (p. 2)

amazon.com/Half-Life-Fact…

2/ NOTE: While the author acknowledges points brought up by the books below, I think he might not give enough attention to those authors' ideas.

Structure of Scientific Revolutions (Thomas Kuhn)

https://twitter.com/ReformedTrader/status/1331998734276653059

Science Fictions (Stuart Ritchie)

https://twitter.com/ReformedTrader/status/1336398442403307521

3/ "Biologists had first visualized the nuclei of human cells in 1912 and counted 48 chromosomes, which was duly entered into the textbooks. In 1953, a well-known cytologist even said that “the diploid chromosome number of 48 in man can now be considered as an established fact.”

4/ 'But in 1956, Tjio and Levan tried a new technique. After counting over and over, they nearly always got only 46 chromosomes.

"Facts change all the time. Smoking has gone from doctor recommended to deadly. Meat used to be good for you, then bad to eat, then good again." (p.2)

5/ "The dinosaurs of our youth—slow, reptilian, and gray-green—are now fast moving, covered in feathers, and the colors of the NBC peacock.

"I am defining 'fact' in a loose fashion, to refer to our individual states of knowledge awareness rather than objective truth." (p. 3)

6/ "The coelacanth is an example of Lazarus taxa: living things that are presumed long extinct until contrary evidence is discovered.

"In 2010, biologists at the University of Queensland in Australia listed 187 mammals very likely to have gone extinct in the past 500 years.

7/ "Then they checked to see how many were eventually recategorized as nonextinct. The answer: More than a third of all mammals that allegedly were lost to time have since been rediscovered." (p. 28)

8/ "Medical knowledge about cirrhosis or hepatitis takes about forty-five years for half of it to be disproven or become out-of-date [see chart below].

"Two Australian surgeons found that half of the facts in that field also become false every forty-five years." (p. 29)

9/ "Given time, most articles will decay into irrelevance. Some of these are not wrong, just obsolete. The effectiveness of treatments doesn’t necessarily become nullified; they are superseded by something newer, such as novel vaccines that make treatment unnecessary." (p. 30)

10/ "The magnetic permeability of iron has changed over time. Specifically, iron has gotten twice as magnetic every five years. This sounds wrong. Shouldn’t the magnetic property of iron be unchanging?

11/ "This was entirely due to technology. As our methods for making pure iron have improved, so have the magnetic properties of iron. Something that seems to be safely in the category of scientific fact is actually intimately intertwined with our technological abilities." (p. 50)

12/ "Similarly, medical advances have progressed so rapidly that travelers from previous centuries, if not decades, would scarcely recognize what we have available to us. Not only does a vaccine exist for smallpox, but the disease has been entirely eradicated from the planet.

13/ "Childbirth has gone from life-threatening to a routine procedure. Bubonic plague, generating a modern wave of the Black Death, is easily treatable with antibiotics.

"There has been a rapid increase in average life span in the developed world over the past hundred years.

14/ "This occurred partly through lower infant mortality and better hygiene, adding added 0.4 years to Americans’ total expected life spans in each year since 1960. But this increase in life span is itself increasing. If the acceleration continues, something curious will happen.

15/ "When we begin adding more than one year to the expected life span—a shift from less than one to greater than one—we get what is called actuarial escape velocity. What this means is that when we are adding more than one year per year, we can effectively live forever." (p. 52)

16/ "Imagine that the magnitude of technological growth is proportional to the amount of knowledge that has come before it.

"An equation in which something grows by an amount proportional to its current size amounts to exponential growth." (p. 57)

17/ "A small group on an island would only have a subset of the knowledge necessary to re-create modern civilization; each person would have only a tiny fraction of the required skills.

"Many economists argue that population growth comes hand-in-hand with innovation." (p. 57)

18/ "It’s a lot easier to spread the first thing you hear, or a fact that sounds correct, than to delve deeply into the literature in search of correct information.

"There are many examples where a small error, despite being corrected later, has spread through a population.

19/ "Whatever fact first appears in print, whether true or not, is very difficult to dislodge.

"James Fallows has worked hard to remove the frog-in-a-pan falsehood from the population; in fact, the frog only remains in a slowly-heated pot if it’s brain-dead." (p. 86)

20/ "If one scientist types a citation incorrectly, there is a mutated version of the citation in the wild. If other scientists look only at that reference and not the original paper, the typo is propagated.

"These 'mutations' reveal the history of the article being cited.

21/ "Simkin & Roychowdhury conclude that only 20% of scientists who cite an article have actually read that paper.

"Be critical before spreading information. Too often, not knowing where one’s facts came from is the source of an error. We often just take things on faith." (p.94)

22/ "A solution might be well-known in one area but still be an open question in another. This allows people who might not be experts to apply what their knowledge. A fact-recombination—ideas brought together in new ways—is one way problems are solved at InnoCentive." (p. 96)

23/ "A long tail of expertise—everyday people in large numbers—has a greater chance to solve a problem than do the experts. The problems that go on to be solved by InnoCentive are precisely the ones that experts can’t solve.

This is behind the concept of the innovation prize.

24/ "The British government offered a prize for the first solution to accurately measure longitude at sea—created in 1714 and awarded to John Harrison in 1773. Other governments had previously offered other prizes for longitude: the Netherlands in 1627 and Spain as early as 1567.

25/ "In 1771, a French academy offered a prize for finding a vegetable that would provide adequate nutrition during a time of famine. The prize was won two years later by Antoine Parmentier for his suggestion of the potato. To our ears, this sounds so obvious as to be silly.

26/ "But the potato, due to its origins in South America, was generally unknown in France. Those who did know thought it was involved in outbreaks of leprosy. Parmentier’s research uncovered a fact known in other parts of the world but which had been hidden in Europe." (p. 102)

27/ "There are many instances when knowledge is not recognized or not combined, because it’s created by people who are simply too far ahead of their time or who come from backgrounds that are different from what is traditionally expected for scientific insight." (p. 106)

28/ "Scientists test a new hypothesis against a version of the world where the hypothesis would not be true. This state of the world, where our hypothesis is not true and all that we see is exactly just as boring as we pessimistically expect, is known as the null hypothesis.

29/ "The larger the sample, the better the test is. The smaller the p-value, the more robust our findings. To publish, you need a p-value <0.05 or, sometimes, <0.01. For 0.05, this means that there is a one in twenty probability that the result being reported is in fact not real!

30/ John Maynard Smith: “Statistics is the science that lets you do twenty experiments a year and publish one false result in Nature.”

The decline effect: "In some situations, repeated examination of an effect or a phenomenon yields results that decrease in magnitude over time.

31/ "Increasingly precise measurement frequently dial the effects downward.

"But the decline effect is not only due to measurement. One other factor involves the dissemination of measurements, and it is known as publication bias (unsuccessful results are rarely published).

32/ "For that one scientist who received an erroneous result (and therefore a low p-value), there is a great deal of excitement.

"However, someone who tries to replicate his work might find no effect at all, or if there is one, it is likely to be smaller." (p. 156)

33/ "Ioannidis examined the most highly cited medical studies. Of 45 papers, 7 exhibited decline effects, and another 7 were contradicted outright by later research.

"Nearly a quarter had never even been re-tested: there could be many more false results than we are aware of.

34/ "From treatment of HIV to angioplasty or strokes, none of these areas were immune to the decline effect. And, of course, a similar range of areas was affected by contradictions: coronary artery disease, vitamin E research, nitric oxide, and more." (p. 157)

35/ Ioannidis: "The differences in the effect sizes could often be within the range of chance variability. Results from clinical studies, especially early ones, should be interpreted using not only the point estimates but also the uncertainty surrounding them."

36/ "More recently, Ioannidis conducted the same test for various biomarkers and found that subsequent meta-analyses often found diminished effects. We must always be aware that we are dwelling in uncertainty. Forgetting can make us jump to unwarranted conclusions." (p. 158)

37/ "Ioannidis’s 2005 paper in the journal PLoS Biology was titled “Why Most Published Research Findings Are False.” As of late 2011, it has been viewed more than four hundred thousand times and cited more than eight hundred times.

38/ "In many situations—whether due to the study being done in a field in which the probability of a spurious relationship is high, or small samples, or an field in which replication isn't attempted—publishable results can occur even though the results are not true." (p. 160)

39/ "The hotter a scientific field, the less likely the research findings are to be true. Any positive result gets a great deal of hype quite rapidly and is pushed out the door quickly but leads to research that can be easily refuted, with an equal amount of hype." (p. 160)

40/ “If a replication attempt confirmed the first researcher’s findings, it would do nothing for the team performing the replication but would win a Nobel Prize for him. On the other hand, if it disconfirmed, there would be nothing positive to show for their work.” (p. 162)

41/ "Only through replication can science be the error-correcting enterprise it is supposed to be.

"Since science prioritizes the exciting, it is nearly impossible to publish that some hypothesis is false (unless the work overturns a well-known result)." (p. 162)

42/ John Ziman: "The scientific literature is strewn with half-finished work, more or less correct but not completed with such care and generality as to settle the matter once and for all.

43/ "The tidy comprehensiveness of undergrad Science, marshalled by the latest complacent generation of textbook writers, gives way to a nondescript land, of bits and pieces and yawning gaps and tiny elegant masterpieces, through which the grad student must find his way." (p.164)

44/ "Mueller defined a war as a conflict between two governments, or a government and an organized group (relevant for a civil war), in which at least one thousand people are killed each year as a direct consequence of the fighting.

45/ "Mueller compiled all of the data since 1946 from a variety of sources and showed that, after an increase from the beginning of the data set until the end of the Cold War, the number of wars has plummeted precipitously (and that the vast majority of wars are civil wars).

46/ "In the past several decades, war has gone from being a common and growing occurrence to something quite rare. But it’s also astonishing for a reason besides its counterintuitive aspect: It could not have been known without careful measurement." (p. 164)

47/ "Taxonomic bias is when we study certain things not because they are more prevalent but because we like them more or because they are simply easier to find. Vertebrates are the subject of the vast majority of papers despite being only a tiny fraction of the types of animals.

48/ "Amphibians and reptiles get less attention than birds and mammals because they are less cuddly.

"What we study is not always what is actually out there. It’s often what we’re interested in or what’s easiest to discover." (p. 169)

49/ "Adhering to something we believe even in the face of change is not unusual.

"In 1920, the New York Times ridiculed Robert Goddard, arguing that thinking that a rocket could work in the vacuum of space was a blatant disregard for a high school understanding of physics.

50/ "The editors went into detail to debunk Goddard. Luckily, the Times was willing to print a correction. The only hitch: They printed it the day after Apollo 11’s launch in 1969." (p. 173)

51/ "Cognitive biases are important aspects of our factual inertia. Even if we are confronted with facts that should cause us to update our understanding of how the world works, we often neglect to do so. We persist in only remembering facts that jibe with what we already know.

52/ "Daniel Kahneman’s idea of theory-induced blindness is “an adherence to a belief about how the world works that prevents you from seeing how the world really works.”

"When looking for one thing, we completely ignore everything else around us.

53/ "This bug is turned into a feature by magicians, who exploit our change blindness. A magician gets you to concentrate on his left hand, while the right hand is doing all the important sleight-of-hand. This can even fool trained magicians who are trying to learn the illusion.

54/ "We have to go out of our way in order to learn something new. Our blindness is not a failure to see the new fact; it’s a failure to see that the facts in our minds have the potential to be out-of-date at all.

55/ "It’s a lot easier to keep on quoting a fact you learned a few years ago than to decide it’s time to take a closer look at the current ten largest cities in the U.S., for example, and to notice that they are far different from what we learned when we were younger." (p. 179)

56/ "Many medical schools inform their students that within several years, half of what they’ve been taught will be wrong; the teachers just don’t know which half.

"But too often, we don’t really live our lives with the concept that facts are always changing." (p. 208)