logical fallacies

Logical fallacies – tools to debunk pseudoscience

What are logical fallacies ?

 

Logical fallacies are essentially errors of reasoning in making an argument. When logically fallacious arguments are used, usually based on bad reasoning to support a position (or to try to convince someone to adopt the same position), it is considered a fallacy.

This means that an argument that uses a logical fallacy shouldn’t hold up to those using logic and reason as the source of decision making. Of course, it generally doesn’t stop people, specifically those pushing pseudoscience or an anti-science point of view, from using them or being swayed by them.

There are two forms of a logical fallacy:

  • Formal–These logical fallacies are those fallacies that violate a particular rule of logic. They almost always include non sequitur logic, that is, the conclusion is not connected to the argument.
  • Informal– arguments that, while not violating logic rules, are invalid because of the content of their argument. Informal fallacies are often characterised by the fact that there is a disconnect of some kind between their premises and conclusions.

Deciding between formal and informal logical fallacies is interesting for logic geeks, but I didn’t want to spend time separating between the two. The net effect of either type of logical fallacy is the same–the arguments can be dismissed.

logical-fallacy-meme

List of logical fallacies

 

Below is a list of the most common fallacies that are used by those who push pseudoscience or deny science – it’s not all inclusive, so I’m missing a bunch:

Appeal to Antiquity or Tradition 

Appeal to Popular Belief 

Appeal to Consequences 

Appeal to Nature 

Appeal to Novelty 

Argument from Fallacy 

Argument from False or Misleading Authority 

Argument from Ignorance 

Argumentum Ad Hominem 

Bandwagon Fallacy 

Cherry Picking or Quote Mining 

Confirmation Bias 

Fallacy of Composition 

Fallacy of Division 

False Dichotomy 

False Equivalence 

Fundamental Attribution Error (or Correspondence Bias) 

Galileo Gambit 

Gambler’s Fallacy 

Genetic Fallacy 

Gish Gallop 

Godwin’s Law

Naturalistic Fallacy 

Nirvana Fallacy 

Non Sequitur 

Poisoning the Well 

Post hoc ergo propter hoc 

Precautionary principle

Red herring

Shill Gambit 

Slippery Slope Fallacy 

Special Pleading 

Strawman Argument

Not all of this list are technically logical fallacies. For example, confirmation bias is really a cognitive bias, not a logical fallacy. However, for reference purposes, I include it because it forms the basis of logical fallacies like “cherry picking.”

For example, confirmation bias, the gambler’s fallacy, and bandwagon fallacies are fallatious not because the violate logic, but because they represent ways in which our natural view of the world may lead us to fallacious conclusions.

Editor’s note: This page was originally published in March 2015. It has been updated to fix some SEO issues, clarify some biases that are not logical fallacies per se, and clean up some spelling issues.

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  • transcendentape

    Some of these can be more accurately described as a cognitive bias rather than as a logical fallacy. Both are to be avoided, but cognitive biases arise from the way we perceive the world while logical fallacies are just incorrect logic.

    For example, confirmation bias, the gambler’s fallacy, and bandwagon fallacies are fallatious not because the violate logic, but because they represent ways in which our natural view of the world may lead us to fallacious conclusions.

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  • http://razzwell.blogspot.com/ Razwell

    “THE Scientific Method” is a TOTAL DISGRACE, EXTREMELY DESCEPTIVE AND INACCURATE and an INSULT to researchers EVERYWHERE, PAST AND PRESENT. LOOK UP DR. WILLIAM MCCOMAS AND PHYSICIST JOHN DENKER. THIS IS WELL UNDERSTOOD BY ALL PROFESSIONAL SCIENTISTS. ALSO GOOGLE SEARCH “the scientific method is crap by physicist TAEMAN COOKE .

    IT IS YOU PEOPLE WHO ARE THE TOTALLY MISINFOMED AND UNEDUCATED IDIOTS…. Up your misinformed asses!!!!!!!

    • glorifing

      lol lol
      hillarious

  • http://razzwell.blogspot.com/ Razwell

    You Internet dorks are uninformed amateurs like OJ Mayo thinking he could beat Jordan. Raptor, you would get you ASS KICKED IN THE PROS,FOOL. Einstein,Perlmutter and others wouLd set you straight about science And HOW IT IS DONE. THERE IS NO SUCH THING AS WHAT IS TAUGHT TO 7TH GRADERS.IT IS A DISGRACE.SCIENCE IS DIFFICULT TO DO.THE SCIENTIFIC METHOD IS AN INSULT TO RESEARCHERS PAST AND PR3SENT…..

    LOOK UO JOHN DENKER,CUNT

  • http://razzwell.blogspot.com/ Razwell

    Nature,the universe is NOT logical. That is why we must keep looking to see what it is telling us. Einstein said that we cannot know about Nature by logical means. Galileo was the first to realize this.

    • http://www.skepticalraptor.com/skepticalraptorblog.php Skeptical Raptor

      You have an extremely low rating on Disqus, probably because you spout nonsense. Go post elsewhere.

      • http://razzwell.blogspot.com/ Razwell

        You are UNEDUCATED. My info COMES STRAIGHT FROM FILIPPENKO LECTURES. NO SUCH THING AS THE SCIENTIFIC METHOD. WHY CANNOT YOU INTERNET WEIRDO DORKS GET IT RIGHT FOR ONCE. THIS WHOLE. Blog is full of MISINFORMATION THAT ACTUAL PROFESSIONAL SCIENTISTS DISAGREE WITH.

      • http://razzwell.blogspot.com/ Razwell

        HARD TO VARY EXPLANATIONS WAS THE missing ingredient THAT WAS RESPONSIBLE FOR HUMAN SCIENTIFIC PROGRESS.

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  • http://beginingsinwriting.wordpress.com/ R.w. Foster

    Is there a “Misuse of the Precautionary Principle” fallacy? That’s one the anti-GMO crowd likes to use on occasion.

    How about “Not Understanding Climate Models,” one?

    • http://www.skepticalraptor.com/skepticalraptorblog.php Skeptical Raptor

      I’m actually adding the Precautionary Principle. It’s not exactly a logical fallacy, but close enough.

      I think climate change is too specific for this page. I need to write a bit more about global warming, and I’ve got to find something that is good and snarky.

      • http://beginingsinwriting.wordpress.com/ R.w. Foster

        I look forward to it. Snarky or not, you deliver with great science.

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