Peculiarities and Principles

I'm still reading through Faith in Crisis edited by Andrew Likoudis.   I got up to the two essays in the first part that talk about "Fundamentalism":

• Rigorism in the Early Church: The First “Fundamentalists” (James L. Papandrea)
• Fundamentalism & Americanism: Obstacles to Thinking with the Church (William Masur, MS)

I stopped somewhere near the beginning of the second article because I became curious about the origin of the term as it is used today to describe Catholics.    It was in fairly frequent use in the USA among Catholic progressives in the later part of Pope Francis's reign, for instance.   I don't hear it so much anymore.

But that's not what this post is about, not directly.    Rather, I have been thinking about the fairly frequent current attempts to label one's opponents or pathologize them.   

To what extent is it legitimate to use an ad hominem line of argument?

The term has an interesting history.   Traditionally, its use in argument is best expressed in English by John Locke, though the concept predated him by centuries:

Argumentum ad hominem consists of pressing a man with consequences drawn from his own principles and concessions.

When you find that someone has said something that is contradicted implicitly or explicitly in another part of his discourse, you can point it out legitimately.    

The modern use of the term apparently comes from Richard Whately in the 19th century.  

 the ad hominem argument is "addressed to the peculiar circumstances, character, avowed opinions, or past conduct of the individual"

In this modern sense it is considered a material fallacy because it doesn't address the argument as such -- its intention is to discredit the opponent by an attack on his character or motives rather than on his reasoning.    This site has more details.    

Some modern thinkers such as Charles Taylor have critiqued the idea that ad hominem is irrelevant as such in the reasoning process.   I have only skimmed the article I linked to.    But it looks like he is arguing for a kind of ad hominem that is quite different from the fallacious rhetorical form of injuring the reputation of the other in order to weaken his argument.   He is saying that to bridge moral or cultural differences that seem irreconciliable, it is not enough to argue from abstractions.   Some form of practical "testimony" seems essential.  

My takeaway from this is that the toxic form of the ad hominem is the one used to damage the credibility and sometimes the entire life of the opponent, the form that ignores the argument altogether.