Common Fallacies in Reasoning

Philosophy 150, Spring 1977

Prof. Kielkopf, The Ohio State University

By Stephen M Golden, Copyright © 17 September 2014

 

I. False or Inaccurate Assumptions: 1

II. Inaccurate Principles. 3

III. Taken in by a Question’s Complexity: 4

IV. Begging the Question (petitio principii). 4

V. Avoiding the Argument. 6

 

I. False or Inaccurate Assumptions:

A. The Appeal to Force (ad baculum): If the falsity of a proposition would make

me suffer; it is not false.

{It will be too bad for me if not-P. Therefore, P is true.}

 

B. The Appeal to Pity (ad misericordiam): If the falsity of a proposition would make another party suffer, it is not false.

{It would be too bad for so-and-so if not-P. Therefore, P is true.}

 

C. The Genetic Fallacy (ad hominem abusive): What a bad person says is false.

{X says P, and X is a bad person. Therefore, P is not true.}

 

D. The Circumstantial Fallacy (ad himinem circumstatial): If X asserts proposition P and it is in X’s interest that P be true, then P is not true.

{X says P. X would benefit by P being true. Therefore, P is not true.}

{X says P. We can predict that someone in X’s position would say P.

Therefore, P is not true.}

{X says P. P is inconsistent with what X says elsewhere. Therefore, P is not true.}

{X says P. P is inconsistent with X’s practice. Therefore, P is not true.}

 

E. The Appeal to Ignorance (ad ignoratium): If a proposition has not been shown to be false, it is true.

{P has not been proven false. Therefore, P is true.}

 

F. The Appeal to Popular belief (ad populum): If a proposition is believed by a vast majority of people, it is true.

{Many, many people say that P is true. Therefore, P is true.}

 

II. Inaccurate Principles.

A. Reliance on cliche’s: “Truth lies in the middle.” “Haste makes waste.” “All people are created equal.” “Justice will triumph in the end.”

 

B. Fixed ideas: “The U.S. cannot have another great depression.”

“Environmental purity can be attained without great cost; it only requires goodwill.”

 

C. Stereotypes of groups: “All of his kind of people are lazy.” “We could never win a land war in Asia because “Asiatics” do not care about their lives and they will let us kill them at a ratio of 10 to 1 until we’re all gone.”

 

 

III. Taken in by a Question’s Complexity:

E.g., Why don’t people who favor legalized abortion think that the unborn have any rights?

It can easily be seen that there is more than one assertion being presented that has

not been proven.

 

 

IV. Begging the Question (petitio principii).

A. A question is answered with a near synonymous statement of what is asked.

E.g., Q: Why do you say I failed? A: You didn’t measure up to minimum performance levels.

 

B. A statement is made as though a claim which is yet to be proven has been proven.

E.g., “The bond issue has to be passed to provide new jobs.” The presupposition here is that the question, “Will the bond issue provide new jobs” has already been asked, and answered affirmatively.

E.g., “Christmas displays on city, state, or federally owned property (Including school grounds) violate the constitutional guarantee of

church-state separation” presupposes the question “Does the constitution guarantee church-state separation?” in the affirmative.

 

C. The justification for a premise is the conclusion.

E.g., “Suicide is wrong. I’ll tell you why it’s wrong. It is wrong because it is against human nature. Now even if people do kill themselves,

we can still say that suicide is against human nature because ‘nature’ can be used in a normative sense. We do not have to mean

by ‘nature’ whatever happens in nature. In the normative sense ‘to be against nature’ means to be contrary to what that thing ought to do. Thus, since humans ought not to kill themselves, suicide is unnatural.”

 

 

V. Avoiding the Argument.

A. Considering a claim, suggestion, or argument only as a candidate for criticism, not as a possible candidate for acceptance.

For example: If someone criticizes our moral behavior, we shift the topic to the difficulties of supporting any moral claim.

 

We could also:

1. Pay attention to the form of the message when the content counts.

E.g., criticize the grammar of an unfavorable evaluation.

2. Pay attention to the content when the form counts.

E.g., defense of bad art because it has a good message.

3. Raise a practical problem when a theoretical issue is in question.

E.g., raise questions about how a theory may be taught when the issue is the truth of the theory.

4. Raise theoretical issues when a practical question is at issue.

 

B. Substitute acceptable reasons for our actions when in fact, we had poor reasons for acting.

1. What I failed to attain was not good; so my failure was not bad.

2. My bad result has these compensating features; so, my choice was not

too bad.