Arguing that because two things share (or are implied to share) some property, they are the same.
Premise: A is a B.
Premise: A is also a C.
Conclusion: Therefore, all Bs are Cs.
- Benny is a con artist. Benny has black hair. Therefore, all people with black hair are con artists.
- Simon, Karl, Jared, and Brett are all friends of Josh, and they are all petty criminals. Jill is a friend of Josh; therefore, Jill is a petty criminal.
Guilt by Association as an Ad Hominem Fallacy
Guilt by association can sometimes also be a type of ad hominem (“to the man”) fallacy.
In this twist of the Guilt by Association fallacy, the argument attacks a person because a specific or singular ideological similarity exists between the person making the argument and another unrelated (and hated) group.
This form of the argument is as follows:
- Source S makes claim C.
- Group G (which is currently viewed negatively by the recipient of source S’s claim) also makes claim C.
- Therefore, source S is viewed as associated with – or similar to – group G, and source S inherits recipient R’s negative perception of group G.
“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?”
In this case, the common interest (similarity) between the Puppy Haters and opponent O is that they both want O to get elected.
Guilt of puppy hating is being assigned to O because O and P.H. have similar political interests. (They may very well have different views on animal cruelty and treatment of puppies.)
Another example of this is when those opposed to “safe spaces” on college campuses – or opposed to the use of recently developed gender-neutral pronouns – are lumped together with white supremacists or the ill-defined alt-right.
While many white supremacists or “alt-righters” may hold similar stances on these issues, this does not mean that everyone who is similarly opposed to “safe spaces” or use of gender-neutral pronouns can be easily classified as a “white supremacist” or a “member of the alt-right”.
The entities in question might share opinions on some issues, but this does not mean that they agree on all issues (e.g. white supremacy, anti-Semitism, misogyny, etc.).
Guilt by Association as an Ad Hominem fallacy is a favorite among proponents of identity politics.
Honor by Association
The logical inverse of “guilt by association” is honor by association, where one claims that someone or something must be reputable, trustworthy, or reliable because of the people or organizations which are related to it or otherwise support it.
Many businesses heavily use the principle of honor by association in their advertisements and marketing. For example, an attractive spokesperson will say that a specific product is good. The attractiveness of the spokesperson gives the product good associations.
Some information and examples taken/adapted from Wikipedia.
Please see disclaimer.