Welcome

This website presents my attempt to make sense of the bewildering subject of bad reasoning. Many philosophers have attempted to name and classify types of fallacies, but no list or classification scheme has so far managed to be comprehensive. This list is also incomplete. In fact, I believe any list of fallacies must necessarily be a work-in-progress, since the use of fallacious reasoning is itself constantly changing. The fallacies that were well-known to the ancient Greeks and Romans were the fallacies used by politicians and orators. We still have politicians and orators today, so those fallacies are still with us; but we also have to keep track of fallacies used by advertisers and the news media. With the advance of science we have had to keep up on the fallacies involved in scientific (and pseudo-scientific) reasoning. As new public institutions emerge, no doubt new forms of fallacious reasoning will arise with them. We logicians need to stay alert.

On this page you will find...

                                                     (Click on the blue letters to go to each part of the page.)

       1.  A DEFINITION of the term "fallacy," and a discussion of the nature of fallacious reasoning.

       2.  A brief HISTORY of the study of fallacies, from the ancient Greeks to the present. (Currently in preparation.)

       3.  An explanation of the PRINCIPLES that I use to classify and organize fallacies.

        4.  A table on which the FALLACIES themselves are organized according to their classification. Click on the class name for a list of fallacies included in that class. Click on each fallacy to see an explanation of that fallacy, a couple pithy examples, a discussion of why we sometimes find that fallacy to be persuasive, and in most cases a source indicating who first described and/or named the fallacy.

        5.  Lots of EXERCISES to give students practice in identifying fallacies, broken into two convenient units.

        6.  A BIBLIOGRAPHY of print sources and websites.

        7.  An INDEX in which fallacy names and other terminology are listed in alphabetical order, with appropriate hyper-links.

About this Site:

This page was created for the use of my General Introduction to Philosophy (PHIL 110), Critical Thinking (PHIL 125), and Logic (PHIL 130) students at Cuyamaca College. Naturally, other visitors are also welcome.

Since it is increasingly important to judge the quality of information on websites, and since one criterion of quality is the credentials of the author, I have attached a copy of my resume.

Another mark of reliability of a website is that the webmaster invites criticisms and corrections. I am pleased to offer that invitation. Anyone who wishes to contact me about the contents of this page is welcome to do so at bruce.thompson@gcccd.net. Indeed, I would like to thank the many people who have contacted me already. As the quality of information on this site improves, it is they who deserve the credit.

FAIR USE OF MATERIAL ON THIS SITE:

The material on this page is not under copyright; and I hereby give permission for this material to be used by others. Note, however, that permission to copy and use material has nothing to do with the concept of plagiarism, which results from failing to adequately cite the source of ones information, or from claiming authorship of material of which one is not the author. As author, I can grant permission for this material to be used by others, but even I cannot grant permission for the material to be plagiarized. No one has that power.

Speaking of plagiarism, some of the examples and exercises may, accidentally, have been taken from other, half-remembered logic books. If so, it is certainly not my intention to claim authorship of material of which I am not the author. It is just that I have used some examples so often over the years that I no longer remember whether I wrote them myself, or borrowed them from another author. Please let me know if you notice any flagrant plagiarisms. I will be glad to remove them, or at least to provide an adequate citation.

A NOTE ON SPELLING:

Alert readers will notice that on this website I use the spelling "premiss" and "premisses" rather than "premise" and "premises." If correctness is to be measured by etymology rather than common practice, these spellings are preferable to the more common spellings. According to Charles S. Peirce (and the Oxford English Dictionary appears to back him up on this), the word "premiss" is derived from a medieval Latin word that refers (just as one would expect) to the portion of an argument in which justification and reasons are offered in support of a conclusion. The word "premise" is derived from a French legal term meaning "aforesaid," and in English has come to be used (usually in the plural) to refer, rather legalistically, to property (and its appurtenances), in such phrases as "to occupy the premises" and "to vacate the premises." I imagine that the custom on legal documents - eviction notices and the like - was to begin with a description of a certain property, and end with a phrase such as "The resident is hereby ordered to vacate the aforesaid." With the French word used regularly in place of "aforesaid," one would soon get the idea that "premises" was a lawyers' term of art meaning "real estate."

It was recently brought to my attention that the two words may actually be etymologically related. The premisses of an argument are traditionally laid down before the conclusion, so they are also "aforesaid," in the same sense as the description of property on a legal document. However, (if Peirce is correct) this etymological connection pre-dates the entry of the two words into English. Hence I still think it is appropriate to consider them to be separate words, sharing only coincidentally the same pronunciation. However confusion over the spelling of the two words is also long-standing. Even a hundred years ago Peirce felt he had to explain his preference for the older (and in his view more correct) spelling, just as I am doing now.

This page last revised 4/29/2008.

Bruce E. R. Thompson
Instructor of Philosophy, Cal State University San Marcos
Instructor of Philosophy and Reference Librarian, Cuyamaca College
Instructor of Philosophy, Southwestern College