Personal Attacks (Ad Hominem Fallacy)
A personal attack (or ad hominem fallacy) is a change from the subject at hand to the person or persons speaking on that subject.
Traditionally, this looks like one person presenting an idea, solution, or issue and another person dismissing it – either publicly or privately – by attacking the person who presented it.
Example of an ad hominem fallacy – or personal attack
In logical form:
Premise 1: Albert has taken a side on the global warming debate.
Premise 2: Albert lives in an energy-sucking mansion.
Premise 3: Albert is a douche nozzle.
Conclusion: We should not believe what Albert says about global warming.
Why it’s erroneous
Albert may be a douche nozzle. He may be a hypocrite. He may even be wrong.
But, if Albert is wrong, it is for a reason, or reasons, besides him being a hypocrite.
To get a better understanding of why, look at it this way. Let’s say that, instead of talking about global warming or something otherwise considered controversial, Albert said, “2 + 2 = 4.”
The statement Albert is making exists completely outside of Albert. He might have ulterior motives for bothering to tell you this. He might also be a horrible person. He could even be a complete idiot he is wrong 99.9% of the time.
But, this equation has existed long before Albert ever came into the picture, and it won’t change simply because Albert has commented on it.
Albert cannot change the truth for simply being an unscrupulous person who has taken a stance on the matter.
At most, Albert’s untrustworthiness suggests that we should not believe what Albert is saying only because it is Albert who said it. We should look to other evidence either in support or contradictory to such claims.