Informal Fallacies

Dated Sep 6, 2016; last modified on Thu, 02 Sep 2021



How can you be against faith when you take leaps of faith all the time: making investments, trusting friends, and even getting engaged?

No True Scotsman

“But John is a programmer, and he is not socially awkward at all.” Yes, but John isn’t a true programmer.


Not a Cause for a Cause

The hacker took down the railway company’s website, and when I checked the train schedule, what do you know, they were all delayed!

A survey shows that more college graduates are homosexual than those with lesser education; therefore education makes people gay.

Promptly reminded of Alex Jones' theory that the US government put chemicals in the water that turn the frogs gay. To be fair though, the Air Force Wright Laboratory won the 2007 Ig Nobel Peace Prize for instigating research & development on a chemical weapon that will make enemy soldiers become sexually irresistible to each other.

Slippery Slope

We shouldn’t allow people uncontrolled access to the internet. They will be frequenting pornographic websites, and soon enough, our entire moral fabric will disintegrate and we will be reduced to animals.

If we allow abortion in the first weeks of pregany, it’ll be impossible to prevent the killing of a full-term infant. Conversely: If the state prohibits abortion even in the 9th month, it’ll soon be telling us what to do with our bodies at the time of conception.

Noteworthy because of how the slippery slope can be applied in reverse.

Unwarranted Assumption

False Dilemma, or Excluded Middle, or False Dichotomy

In the war on fanaticism, there are no sidelines; you are either with us or with the fanatics.

If you’re not part of the solution you’re part of the problem.

Short-term vs. long-term, e.g. Why explore fundamental science when we have so huge a budget deficit?"

Composition and Division

Each module in this software system has been subjected to a set of unit tests and passed them all. Ergo, no need for integration tests.

Begging the Question

Circular Reasoning

You’re utterly wrong because you’re not making any sense.

Weak Analogies & Unrepresentative Sample

Hasty Generalization

Asking 10 people on the street what they think of the president’s plan to reduce the deficit can in no way be said to gauge the sentiment of the entire nation.

Missing Data

Appeal to Ignorance

There is no compelling evidence that UFOs are not visiting the Earth; therefore, UFOs exist.

Suppressed Evidence, or Half Truths

These government abuses demand a revolution, even if you can’t make an omelette without breaking some eggs. Will more people die in the revolution than under the current regime? Are all revolutions against oppressive regimes desirable and in the interests of the people?


  1. An Illustrated Book of Bad Arguments: Chapter 1. Informal Fallacies. Almossawi, Ali. . Dec 5, 2013. ISBN: 978-0989931205 .
  2. The Fine Art of Baloney Detection. Sagan, Carl. . 1996.
  3. Improbable Research. . 2007.