In debates there’s a particular logical fallacy that goes something like:
“Person A is bad. Person A thinks X is good. Therefore X is bad.”
“Person A is good. Person A thinks X is good. Therefore X is good.”
Essentially X is judged based on who likes/dislikes it, rather than on its own merits.
I’m wondering if there’s a term for this particular type of logical fallacy? I’m not sure if it counts as ‘ad hominem’, since Person A is not the debater. It’s also not quite ‘Appeal to Authority’ since Person A is not necessarily an important person. Any ideas?
It is guilt by association. Guilt by association is one variant of the association fallacy (as @sumelic mentioned in a comment). The other is honor by association, which consists in arguing that if a group I view positively holds a certain claim to be true, then I should believe that claim too.
For guilt by association, Wikipedia gives an example similar to yours:
Guilt by association can sometimes also be a type of ad hominem fallacy, if the argument attacks a person because of the similarity between the views of someone making an argument and other proponents of the argument.
This form of the argument is as follows:
- Source S makes claim C.
- Group G, which is currently viewed negatively by the recipient, also makes claim C.
- Therefore, source S is viewed by the recipient of the claim as associated to the group G and inherits how negatively viewed it is.
An example of this fallacy would be “My opponent for office just received an endorsement from the Puppy Haters Association. Is that the sort of person you would want to vote for?”
The Nizkor Project has a page about guilt by association as a logical fallacy.