Ad Hominem Circumstantial (Bias Ad Hominem)
Attacking an argument by pointing out the arguer's bias or vested interest, which may undermine credibility but does not automatically refute the argument.
THE IDEA
Example 3
A Monsanto representative argues that the company’s genetically modified seed is perfectly safe because of studies, A, B, and C. Steve responds by saying that what the Monsanto representative says can’t be trusted because it has so much invested in the genetically modified seed and would lose too much if the studies indicated the seed was unsafe.
This case is interesting as Monsanto’s bias is easy to see. However, is the vested interest Monsanto has enough to indicate a problematic bias, one that indicates less credibility or trustworthiness? It is difficult without further information to say for sure. One thing that would be relevant would be the nature of the studies cited by Monsanto. Who paid for them? What journals were they published in? If, for example, Monsanto paid for them and published them in something like Monsanto’s Agri‐Journal, then that may well be reason to think that they have a problematic sort of bias and that, therefore, the representative’s credibility has been impugned. The next question, of course, concerns what exactly the respondent’s conclusion is. If it is that the representative’s argument/position is refuted, then that would be a fallacious inference. What about if the conclusion is that the representative’s position/argument is questionable and in need of further evidence from an unbiased party?
When to use it
Debating corporate claims about product safety where financial interests are involved.
Evaluating political arguments where the speaker's party affiliation may introduce bias.
Assessing scientific studies funded by industry sponsors.
FROM THEORY TO EVERYDAY LIFE
In practice
Monsanto and Safety Studies
A Monsanto representative cites studies A, B, and C to argue that their GMO seed is safe. Steve dismisses the argument because Monsanto has a vested interest in the seed’s safety. The fallacy occurs if Steve concludes the argument is false; it is not fallacious if he questions credibility and calls for unbiased evidence.
A MOMENT TO REFLECT
Put it to work.
When is it legitimate to question an arguer's bias, and when does it become a fallacy?
If you suspect bias, what additional information would you need to evaluate the argument fairly?
How does the conclusion you draw (refutation vs. need for more evidence) affect whether you commit the fallacy?
CONTINUE THE CONVERSATION
Source texts
- Bad Arguments 100 of the Most Important Fallacies in Western Philosophy (Steven Barbone, Michael Bruce)