Lecture Notes by Christopher Lay

Los Angeles Pierce College

Department of History, Philosophy, and Sociology

Mathew Van Cleave's 2016 Introduction to Logic and Critical Thinking

https://open.umn.edu/opentextbooks/BookDetail.aspx?bookId=457

Chapter 4 "Informal fallacies", § 3 "Fallacies of Relevance," Sub-§ 1 "Ad Hominem"

"In an ad hominem fallacy, instead of responding to (or attacking) the argument a person has made, one attacks the person him or herself." 

"In short, one attacks the person making the argument rather than the argument itself."   

"[W]hen considering an argument that has been given, we don’t have to establish the arguer’s credibility because we can assess the argument they have given on its own merits." 

"The arguer’s personal life is irrelevant."

[(]"'Ad hominem' is a Latin phrase that can be translated into English as the phrase, 'against the man.'"[)]

Hypocrites

"Even if it were true that [an arguer is] a total hypocrite, [the arguer's] argument may nevertheless be rationally compelling." 

"And it is the quality of the argument that we are interested in, not [the arguer's] personal life and whether or not [the arguer] is hypocritical." 

"Whether [the arguer] is or isn’t a hypocrite, is irrelevant to whether the argument [the arguer] has put forward is strong or weak, valid or invalid. The argument stands on its own and it is that argument rather than [the arguer] that we need to assess." 

Being Compelling is Not Enough

"Nonetheless, there is something psychologically compelling about the question: Does [an arguer] practice what [the arguer] preaches?" 

"I think what makes this question seem compelling is that humans are very interested in finding 'cheaters' or hypocrites—those who say one thing and then do another." 

"Evolutionarily, our concern with cheaters makes sense because cheaters can’t be trusted and it is essential for us (as a group) to be able to pick out those who can’t be trusted." 

"That said, whether or not a person giving an argument is a hypocrite is irrelevant to whether that person’s argument is good or bad."

"So, there may be psychological reasons why humans are prone to find certain kinds of ad hominem fallacies psychologically compelling, even though ad hominem fallacies are not rationally compelling." 

Exceptions

"Not every instance in which someone attacks a person’s character is an ad hominem fallacy." 

"Suppose a witness is on the stand testifying against a defendant in a court of law." 

Here, a "witness’s credibility" is a relevant consideration.   

"[B]ringing up things about the witness’s past, [can be] relevant to establishing the witness’s credibility." 

Example

Is this a fallacy?  Either way, explain why or why not. 

That "Nevada" leader's ideas on taxation are bologna!  Distribute tax revenue to benefit the citizens?!?  Do you know what that leader does on the weekends in the bedroom?  Hell, that leader wasn't even born in Nevada! 

Example

Is this a fallacy?  Either way, explain why or why not. 

You shouldn't believe that philosophy professor's argument about validity, he dresses like an archeologist!