Guide to Rhetorical Fallacies

Here is a nice, printable, breakdown of fallacies commonly deployed in argument. Helpfully, the authors have also provided an example of analysis, applying the typology to a published opinion on same-sex marriage penned by Cardinal O’Brien, Britain’s foremost catholic cleric.


  1. This is very nicely done. One may keep in mind as well How to Lie with Statistics by Darrell Huff from 1954, still in print and a good read.

  2. It’s easy to make a strong argument (with examples) that many of the listed fallacies are description of valid modes of argument in law.

  3. I second David. These are only fallacies if we are thinking about strictly deductive arguments. If we think about what might make us update our prior belief about the likelihood of something being true, expert opinion, general opinion, tradition, etc. might be perfectly good reasons to change our minds.

  4. I am inclined to follow David and Gareth: the fact that a proposition is not logically necessary does not mean that it is false. Not all valid arguments are syllogisms.

    However, the guide is useful because it makes us examine our reasons for believing what we believe, and may send us looking for better evidence. “The life of law is not logic but experience.”

  5. As written by Oliver Wendell Holmes in The Common Law (Boston: Little, Brown & Co., 1981) at p. 1:

    “The life of the law has not been logic: it has been experience. The felt necessities of the time, the prevalent moral and political theories, intuitions of public policy, avowed or unconscious, even the prejudices which judges share with their fellow-men, have had a good deal more to do than the syllogism in determining the rules by which men should be governed.”