The Ad Hominem Fallacy is not a Fallacy

There are a couple of ways to make this argument. The first, and perhaps least courageous, is through an appeal to epistemic learned helplessness. A skilled sophist can construct a convincing argument for any claim, regardless of its truth value — so unless you’re willing to do a ton of work checking facts and validating syllogisms, you shouldn’t put much weight on how convincing an argument seems at first. You should probably put much more weight on the secret motives and beliefs of the arguer. So if, ad hominem, that person actually is a fascist, or a communist, or an evil lizard person, or whatever — that information is valuable to you as a truth seeker.

A second, related argument, comes from Pareto’s Mind and Society, and goes something like this. (1) People have some set of impulses and intuitions, called “residues”. These non-rational residues are the dominant, driving force in determining their beliefs and behaviors. (2) To justify these beliefs and behaviors, people come up with rationalizations, called “derivations”. The derivations play little to no role in determining beliefs or behaviors, but they are handy in justifying them to others.

If you take the derivations at face value, engaging with them rationally, you’re bound for confusion and frustration. It’s better to see them as the ornamental outgrowth from some underlying residue.

As a specific example: One might find it confusing that the environmental movement was so viciously opposed to nuclear energy, given how safe and environmentally-friendly fission power plants are. “We need to stop polluting the planet,” the environmentalist might argue. “Great! Here’s a power source that will let us cleanly consume as much energy as we want,” the naive engineer might respond, and then be confused by why he sees a scowl.

This is not confusing at all to Pareto, who would say that the engineer is engaging with the derivation without understanding the residue — which, in this case, might be some form of “ergophobia” or even an anti-human sentiment. Quoted from Where is my Flying Car?, Jeremy Rifkin: “The prospect of cheap fusion energy is the worst thing that could happen to the planet.” Paul Ehrlich: “Giving society cheap, abundant energy would be the equivalent of giving an idiot child a machine gun.” Amory Lovins: “It would be little short of disastrous for us to discover a source of clean, cheap, abundant energy, because of what we might do with it.” David Graber: “Until such time as Homo sapiens should decide to rejoin nature, some of us can only hope for the right virus to come along.” If you’re choosing someone to set energy policy, the ad hominem information might be more useful than the arguments.

As a parting thought: consider the AI safety movement through this lens.