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Empty edicts – absence of empirical evidence.

February 29, 2012
If it isn’t supported by evidence from real-world tests, it isn’t science, it’s a red flag.

How to recognise this tactic

This tactic shows up when people make claims in the form of bald statements – “this is the way it is” or “this is true” or “I know/believe this” or “everybody knows this” – without any reference to supporting evidence.

‘I had,’ said he, ‘come to an entirely erroneous conclusion which shows, my dear Watson, how dangerous it always is to reason from insufficient data.’

Sherlock Holmes, 1891

1922 Halloween Colds-Chills-Malaria Card

Why do people use this tactic?

People who use this tactic don’t want to put their ideas through real-world testing, which is one of the hallmarks of real science. They want you to accept their claims on their authority alone. Usually, this is because their claims have no foundation.

What’s wrong with this tactic?

Empirical evidence consists of recorded data, collected from the real world by some kind of measurement technique which is reliable and accurate. Without such evidence, anyone can make any claim they like about the way the world is. And as Sherlock Holmes realized, in most cases the claims will be wrong.

The preferred situation is that any scientific conclusion should be backed up by multiple independent lines of evidence. In a scientific report, the data should be supplied. A non-technical article may not supply the actual evidence, but it should cite sources where you can find the evidence.

Bogus science likes to appeal to authorities instead of supplying evidence. If a claim is not supported by evidence it is worthless, no matter who makes it.

What to do when confronted by this tactic

  • Always be sceptical of claims made without supporting evidence.
  • If possible, ask to see evidence or references to studies containing the evidence. Is the claim based on only one or two studies?

Variations and related tactics

This tactic is related to wishful thinking, in which a person desires something to be true and avoids subjecting it to tests in case they show it is not. Some scammers try to give the impression of supporting evidence by resorting to anecdotes or appealing to ‘common sense’. Neither is acceptable to real science.


  • Climate-change deniers use this tactic repeatedly. In a 2011 address, Cardinal George Pell implied that the percentage of CO2 in the atmosphere is too small to be of concern, and that there is some sort of conspiracy to withhold this data from us:





In reality, the 390 ppm of CO2, small as it may seem, is responsible for the maintenance of the planet’s greenhouse effect. Without it, average global temperature would be 30 degrees Celsius lower than it is now. Both the amount of carbon dioxide in the air and its role in the greenhouse effect are routine aspects of any junior secondary school science course.

  • Many alternative health treatments claim they are able to “boost the immune system”. In fact, the concept of ‘boosting’  the immune system makes no scientific sense.
  • Here’s a video about “earthing” which is full of empty edicts, among them such nonsense statements as:

    When we make direct contact with the surface of the earth, our bodies receive a charge of energy that makes us feel better, fast.

    There’s a good debunking of this video at The Soap Box.

Further reading

“I just know” replaces systematic reviews at top of evidence pyramid at the spudd.


Why People “Fly from Facts” by Troy Campbell and Justin Friesen at Scientific American.

Add to the list of examples by leaving a comment.

Sherlock Holmes’ quote is from ‘The Adventure of the Speckled Band’ in Arthur Conan Doyle’s The Adventures of Sherlock Holmes.
The “Colds during cold days” image is from halloween_guy on Flickr.
The Evidence Pyramid is from the spudd.

  1. When Donald Trump appeared before the Scottish Parliament he was pressed for facts to back up his claims that wind turbines damage tourism, jobs and birds. He famously replied “I am the evidence”.

Trackbacks & Pingbacks

  1. Bad science checklist for GMO opponents | Skeptical Raptor's Blog
  2. Boosting the immune system–sorting science from myth



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