I see this one a lot with Politicians.
Historical archive only. New interaction is disabled.
Original Question
Politician 1 and Politician 2 are in an election competition to look good to win.
Both Politicians have a vested interest in looking good to win.
Politician 2 claims Politician 1 did something bad which makes Politician 1 look bad.
Therefore, Politician 1 says the claim is false because Politician 2 is just trying to make him look bad so that Politician 2 can win.
Answers
2Politician 2 claims that something bad about politician 1 is true
Politician 1 points out that politician 2 has vested interest for what he said to be true
Therefore, what politician 2 said is false.
An exception would be like the following: Holly and Josh are betting on opposing teams to win. Josh had to leave and missed the game. He later then asks Holly who won. Holly says that it was her team. Josh says playfully "you only say that because you want to win."
Although Josh is committing a fallacy, he should be suspicious if the stakes were higher, like having bet a lot of money and Josh barely knows Holly.
Ad Hominem Circumstantial. This is the Appeal to Motive, where you say a claim is wrong because of someone's vested interest. Formally this does not follow, since truth is neutral to the motive of the person making the claim (though they will need evidence), although extreme bias may make us - reasonably - less likely to trust them. However, saying it is outright false is not correct.
Vested interest does not imply falsity.
Master Logical Fallacies Online
Take the Virversity course and sharpen your reasoning skills with structured lessons.
View Online Course