In defence of the ad hominem ‘fallacy’

An online trend that’s been infuriating me lately is the smug overuse of so-called ‘logical fallacies’. You know the type. Those short-form pseudo-intellectuals who, much to your horror, spout second-hand philosophy behind a ring light in a rented bedroom, sandwiched between your daily dose of ‘brain rot’ content.

They love to ‘call out’ logical fallacies like they’re performing some kind of intellectual execution. And their favourite, by far, is the ad hominem fallacy, wielded like a moral weapon to castigate anyone who dares to speak with a bit of personality or social awareness.

As they have it, any observations you make about someone’s identity or character can have no bearing on whether you accept their opinion or not. This sounds nice and potentially makes debate more ‘egalitarian’. However, in reality, it relies on a false abstraction, as if the argument itself exists in a vacuum, outside the social realities that give it meaning.

No one arrives at a passionately held view in a sterile, scientific vacuum. So, of course, who they are, their motives, insecurities, identity, and background all matter

The ad hominem fallacy, in its strict sense, means undermining someone’s opinion by appealing to something about them instead of their argument. So, saying “you’re wrong about policy X because you’re rich” would count as ad hominem. The person’s wealth shouldn’t, in pure logical terms, affect the truth of their statement. And fine, I’m not about to hand in an essay arguing via personal attacks. But pretending that’s how we should operate in real-world discourse is absurd.

In actual conversation, we rarely ever have expert-level knowledge of what we’re discussing, therefore, we can’t typically evaluate the truth of someone’s claims directly. But what we can assess, and what our species is remarkably good at assessing, is the person making those claims. People are biased. They form opinions that serve their own ego, their own tribe, and their own self-affirming narratives. No one arrives at a passionately held view in a sterile, scientific vacuum. So, of course, who they are, their motives, insecurities, identity, and background all matter.

Therefore, when someone goes ad hominem against an argumentative adversary, what they’re really doing is applying basic social intelligence. They’re not declaring their argument false in the positive sense – they’re noticing that their reasoning might be motivated. There’s a difference between saying ‘you’re wrong because of who you are’ and saying, ‘given who you are, I have reason to doubt your objectivity.’ The first is bad logic. The second is common sense.

Knowledge isn’t just built by the number of hours clocked in the library. More often, it’s shaped by the empirical data people gather through their day-to-day experiences

Take a simple example. You argue that wealth should be taxed more heavily than income. Your friend, who happens to live in a giant house with a huge trust fund, instantly launches into a long monologue about why that’s practically ‘impossible’, citing obscure legislation you neither have the time nor the will to check. Are you ‘committing a logical fallacy’ by noticing that his stance might, just possibly, be influenced by his own financial interests? Of course not, you’re just being psychologically real.

Or suppose your alcoholic mate starts giving you a detailed lecture, complete with ‘studies’ and ‘sources’, about how drinking wine every night has health benefits. My first reaction wouldn’t be to fact-check PubMed – it would be to laugh because it’s obvious what’s going on. Their ‘research’ is being guided by their addiction. Their motives are baked into their conclusion.

Further still, when we decide whether to value someone’s opinion on a topic, we usually do so because we recognise that they possess a certain level of knowledge. But knowledge isn’t just built by the number of hours clocked in the library. More often, it’s shaped by the empirical data people gather through their day-to-day experiences. And who someone is, their background, circumstances, and identity naturally affect what kind of experiences, and therefore what kind of knowledge, they can have.

We can make reasonable and valid assumptions about the quality of knowledge a person has in virtue of their identity and lived experience

To spell this out: imagine a university wants to determine whether its buildings are accessible for disabled students, so it issues a survey to all students. It’s obvious that the university would get a far more accurate answer if the survey responses came primarily from disabled students themselves. Why? Because by being disabled, they have direct, relevant experience – the kind of empirical insight that others simply can’t access. So, as this example shows (and the same logic applies to many socio-economic issues), we can make reasonable and valid assumptions about the quality of knowledge a person has in virtue of their identity and lived experience.

So maybe in the sterile, artificial world of formal logic, ad hominem reasoning doesn’t cut the mustard. But, in the real world, especially as our grasp on truth becomes ever more obscured, I will shamelessly analyse who you are before accepting or rejecting what you have to say.