How the Sagan standard can help you make better decisions

The noted astronomer and author Carl Sagan came up with a famous dictum acronymed ECREE.

  • Carl Sagan famously shared the aphorism "Extraordinary Claims Require Extraordinary Evidence."
  • This approach can help us fight off fake information.
  • Scientific thinkers in centuries before Carl Sagan also expressed similar sentiment.


Is there an omnipotent all-knowing entity, otherwise known as "God", ruling our daily affairs and caring enough to judge our behaviors on an individual basis? Or is our life ruled by an invisible supercomputer that pre-ordains most of our actions, ensuring an impenetrable veil between us and reality, preventing all knowledge of the true nature of things? Or maybe there are advanced aliens out there, either responsible for guiding our meager attempts at civilizing or simply using us as guinea pigs in some incomprehensible experiment? Whatever it is that is really going on, the late astronomer Carl Sagan coined an aphorism to deal with just such grand proposals. "Extraordinary Claims Require Extraordinary Evidence," asserted Sagan in what has become known as the Sagan Standard. The same can also be referred to by the aphorism's acronym "ECREE".

While Sagan made the statement popular on his "Cosmos" shows of the 1980s, he wasn't necessarily the one who came up with the idea entirely on his own. Historians have pointed to a similar thought expressed in 1899 by the Swiss psychologist Théodore Flournoy who stated that "the weight of evidence for an extraordinary claim must be proportioned to its strangeness". Flournoy, in his turn, actually based his idea on an 1814 saying by the French scientist and philosopher Pierre-Simon Laplace, who said "we ought to examine [seemingly inexplicable phenomena] with an attention all the more scrupulous as it appears more difficult to admit them".

Pierre-Simon, marquis de Laplace

19th century portrait

Other historians even go farther back, seeing the roots of this kind of thinking in 18-century critiques of magic by people like the Scottish philosopher David Hume, who wrote in 1748: "A wise man ... proportions his belief to the evidence", and "No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish."

Certainly, while there are large amounts of humans who still believe in actual miracles, we are also constantly bombarded by claims of both scientific and unscientific nature that beggar belief. ECREE can be a useful tool to keep in mind next time you encounter an outlandish political statement, a deepfake video, or an unprovable claim of a cure for cancer or alien sighting. Don't take outlandish statements for granted and ask for evidence. The greater the claim, the greater the amount of evidence required to prove it.

It’s Getting Harder to Spot a Deep Fake Video

While the idea behind the Sagan standard seems intuitively clear at first glance, to our science-minding modern brains, it has been the subject of criticism. Some, like the geologist and geophysicist David Deming, have argued that Sagan's dictum doesn't really define "extraordinary". After all, what is extraordinary to someone depends on their level of knowledge and their beliefs. Someone who knows very little would find many things beyond ordinary. It is also true that much of what is known scientifically today was not known even a hundred years ago, so certainly many claims which we generally agree upon now could be considered "extraordinary" by previous generations.

What this results in is that the popular concept has been used to bolster up orthodoxy and discredit innovation and research into science anomalies or even mainstream hypotheses which have much empirical evidence.

Still, keep that in mind, it can be a useful tool in these extraordinary times.

Carl Sagan's most important lesson about science

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Photo: Luisa Conlon , Lacy Roberts and Hanna Miller / Global Oneness Project
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Experts are already predicting an 'active' 2020 hurricane season

It looks like a busy hurricane season ahead. Probably.

Image source: Shashank Sahay/unsplash
Surprising Science
  • Before the hurricane season even started in 2020, Arthur and Bertha had already blown through, and Cristobal may be brewing right now.
  • Weather forecasters see signs of a rough season ahead, with just a couple of reasons why maybe not.
  • Where's an El Niño when you need one?

Welcome to Hurricane Season 2020. 2020, of course, scoffs at this calendric event much as it has everything else that's normal — meteorologists have already used up the year's A and B storm names before we even got here. And while early storms don't necessarily mean a bruising season ahead, forecasters expect an active season this year. Maybe storms will blow away the murder hornets and 13-year locusts we had planned.

NOAA expects a busy season

According to NOAA's Climate Prediction Center, an agency of the National Weather Service, there's a 60 percent chance that we're embarking upon a season with more storms than normal. There does, however, remain a 30 percent it'll be normal. Better than usual? Unlikely: Just a 10 percent chance.

Where a normal hurricane season has an average of 12 named storms, 6 of which become hurricanes and 3 of which are major hurricanes, the Climate Prediction Center reckons we're on track for 13 to 29 storms, 6 to 10 of which will become hurricanes, and 3 to 6 of these will be category 3, 4, or 5, packing winds of 111 mph or higher.

What has forecasters concerned are two factors in particular.

This year's El Niño ("Little Boy") looks to be more of a La Niña ("Little Girl"). The two conditions are part of what's called the El Niño-Southern Oscillation (ENSO) cycle, which describes temperature fluctuations between the ocean and atmosphere in the east-central Equatorial Pacific. With an El Niño, waters in the Pacific are unusually warm, whereas a La Niña means unusually cool waters. NOAA says that an El Niño can suppress hurricane formation in the Atlantic, and this year that mitigating effect is unlikely to be present.

Second, current conditions in the Atlantic and Caribbean suggest a fertile hurricane environment:

  • The ocean there is warmer than usual.
  • There's reduced vertical wind shear.
  • Atlantic tropical trade winds are weak.
  • There have been strong West African monsoons this year.

Here's NOAA's video laying out their forecast:

But wait.

ArsTechnica spoke to hurricane scientist Phil Klotzbach, who agrees generally with NOAA, saying, "All in all, signs are certainly pointing towards an active season." Still, he notes a couple of signals that contradict that worrying outlook.

First off, Klotzbach notes that the surest sign of a rough hurricane season is when its earliest storms form in the deep tropics south of 25°N and east of the Lesser Antilles. "When you get storm formations here prior to June 1, it's typically a harbinger of an extremely active season." Fortunately, this year's hurricanes Arthur and Bertha, as well as the maybe-imminent Cristobal, formed outside this region. So there's that.

Second, Klotzbach notes that the correlation between early storm activity and a season's number of storms and intensities, is actually slightly negative. So while statistical connections aren't strongly predictive, there's at least some reason to think these early storms may augur an easy season ahead.

Image source: NOAA

Batten down the hatches early

If 2020's taught us anything, it's how to juggle multiple crises at once, and layering an active hurricane season on top of SARS-CoV-2 — not to mention everything else — poses a special challenge. Warns Treasury Secretary Wilbur Ross, "As Americans focus their attention on a safe and healthy reopening of our country, it remains critically important that we also remember to make the necessary preparations for the upcoming hurricane season." If, as many medical experts expect, we're forced back into quarantine by additional coronavirus waves, the oceanic waves slamming against our shores will best be met by storm preparations put in place in a less last-minute fashion than usual.

Ross adds, "Just as in years past, NOAA experts will stay ahead of developing hurricanes and tropical storms and provide the forecasts and warnings we depend on to stay safe."

Let's hope this, at least, can be counted on in this crazy year.

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