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.

How the Sagan standard can help you make better decisions
  • 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.

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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

A new study says it's okay to eat red meat. An immediate uproar follows.

Even before publication, health agencies were asking the journal not to publish the research.

Photo by Isa Terli/Anadolu Agency/Getty Images

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  • A new study in the Annals of Internal Medicine found little correlation between red meat consumption and health problems.
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CRISPR therapy cures first genetic disorder inside the body

It marks a breakthrough in using gene editing to treat diseases.

Credit: National Cancer Institute via Unsplash
Technology & Innovation

This article was originally published by our sister site, Freethink.

For the first time, researchers appear to have effectively treated a genetic disorder by directly injecting a CRISPR therapy into patients' bloodstreams — overcoming one of the biggest hurdles to curing diseases with the gene editing technology.

The therapy appears to be astonishingly effective, editing nearly every cell in the liver to stop a disease-causing mutation.

The challenge: CRISPR gives us the ability to correct genetic mutations, and given that such mutations are responsible for more than 6,000 human diseases, the tech has the potential to dramatically improve human health.

One way to use CRISPR to treat diseases is to remove affected cells from a patient, edit out the mutation in the lab, and place the cells back in the body to replicate — that's how one team functionally cured people with the blood disorder sickle cell anemia, editing and then infusing bone marrow cells.

Bone marrow is a special case, though, and many mutations cause disease in organs that are harder to fix.

Another option is to insert the CRISPR system itself into the body so that it can make edits directly in the affected organs (that's only been attempted once, in an ongoing study in which people had a CRISPR therapy injected into their eyes to treat a rare vision disorder).

Injecting a CRISPR therapy right into the bloodstream has been a problem, though, because the therapy has to find the right cells to edit. An inherited mutation will be in the DNA of every cell of your body, but if it only causes disease in the liver, you don't want your therapy being used up in the pancreas or kidneys.

A new CRISPR therapy: Now, researchers from Intellia Therapeutics and Regeneron Pharmaceuticals have demonstrated for the first time that a CRISPR therapy delivered into the bloodstream can travel to desired tissues to make edits.

We can overcome one of the biggest challenges with applying CRISPR clinically.

—JENNIFER DOUDNA

"This is a major milestone for patients," Jennifer Doudna, co-developer of CRISPR, who wasn't involved in the trial, told NPR.

"While these are early data, they show us that we can overcome one of the biggest challenges with applying CRISPR clinically so far, which is being able to deliver it systemically and get it to the right place," she continued.

What they did: During a phase 1 clinical trial, Intellia researchers injected a CRISPR therapy dubbed NTLA-2001 into the bloodstreams of six people with a rare, potentially fatal genetic disorder called transthyretin amyloidosis.

The livers of people with transthyretin amyloidosis produce a destructive protein, and the CRISPR therapy was designed to target the gene that makes the protein and halt its production. After just one injection of NTLA-2001, the three patients given a higher dose saw their levels of the protein drop by 80% to 96%.

A better option: The CRISPR therapy produced only mild adverse effects and did lower the protein levels, but we don't know yet if the effect will be permanent. It'll also be a few months before we know if the therapy can alleviate the symptoms of transthyretin amyloidosis.

This is a wonderful day for the future of gene-editing as a medicine.

—FYODOR URNOV

If everything goes as hoped, though, NTLA-2001 could one day offer a better treatment option for transthyretin amyloidosis than a currently approved medication, patisiran, which only reduces toxic protein levels by 81% and must be injected regularly.

Looking ahead: Even more exciting than NTLA-2001's potential impact on transthyretin amyloidosis, though, is the knowledge that we may be able to use CRISPR injections to treat other genetic disorders that are difficult to target directly, such as heart or brain diseases.

"This is a wonderful day for the future of gene-editing as a medicine," Fyodor Urnov, a UC Berkeley professor of genetics, who wasn't involved in the trial, told NPR. "We as a species are watching this remarkable new show called: our gene-edited future."

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A new government report describes 144 sightings of unidentified aerial phenomena.

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