Critical Thinking Toolkit: The Ad Hominem Fallacy

This one really should go without saying… and yet we need to say it anyways. So often, public discourse gets bogged down in personal insults of one variety or another. Whether attacks on a person’s morality, integrity, honesty, educational background, or any other aspect of life, our culture – especially the so-called “cancel culture” – is saturated with efforts to discredit people based on perceived wrongs. On the level of intellectual argument, however, this practice is completely unacceptable and has a name.

Some Obvious Ad Hominem Fallacies

Arguments of this sort are called arguments ad hominem, or ad hominem fallacies. To show as clearly as possible the nature of an ad hominem fallacy, I pose the following dilemma to you.

Hitler believed that 2+2=4. Do you really want to agree with Hitler?

Our emotions might repulse here – we know Hitler was an evil man. But, once the emotional reaction clears up, this is completely silly. Hitler’s being evil has nothing at all to do with whether or not he was right when he said that 2+2=4. That is irrelevant. We can construct a similar-but-opposite example. What if someone walked up to you and said:

Martin Luther King, Jr. believed 2+2=5. How dare you disagree with him! Are you racist or something?

Clearly, the issue here is the same. MLK was a great man, but I can completely agree with MLK goals for social reform without agreeing that 2+2=5. This is not to say that MLK actually believed 2+2 was 5, surely he knew better. But this example makes a point – just because someone is virtuous doesn’t mean you should believe everything they say.

Less Obvious Examples of Ad Hominem

After looking at such obvious examples, it would be natural to think that intelligent people never stoop to this level. And yet, it happens more than people think.

Sadly, this is the majority of political discourse I see today. Those on the left generally paint all conservatives as racist, or at least with not caring about issues of racism, and on that basis (and other similar derogatory remarks) dismiss the entire conservative viewpoint. Conservatives quite often use labels of socialism and communism in similar ways. It isn’t that there aren’t racist conservatives or that there aren’t liberals who genuinely do want socialism or communism – there are. But you can’t just call someone a nasty name and then dismiss them altogether. That’s just not how things work. You’d be laughed out of any intelligent discussion if you take that approach. Sadly, this is largely the state of our world now. By and large, humanity does not know how to dialogue without resorting to insults. This is not surprising – we are never taught how to do so. But it is also extremely disappointing.

But ad hominem doesn’t just arise in moral situations. It also arises on the level of intellect. For instance, a statement like “well I don’t have to listen to you because you don’t have a Ph.D” is an ad hominem fallacy. Whether or not the person you are talking to has a Ph.D, they might be right or they might be wrong. That just isn’t relevant. Rational debate must focus not on the people, but on the subject matter. General relativity, whether stated from the mouth of Hitler or Mother Theresa, whether by Einstein or a confused third-grader reading off of a page, is equally true or equally false. None of those factors matter.

You’d think people don’t do this, but they do – I have been in situations where people responded to points I made by accusing me of lying about my credentials, which is a type of ad hominem attack. In fact, accusing someone of lying is always an ad hominem attack. You can’t prove someone is incorrect by accusing them of lying. Rather you must show in an objective way that the person is either intentionally lying or honestly mistaken.


Writing this post at all leaves a bad taste in my mouth. I don’t even want to speak with people who resort to those tactics. The thing to learn from all of this is that we must always be very careful to ensure that, when we are in a debate, we are focused not on the person, but on their words and whether or not the ideas involved are true or false.

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