Logical Fallacies Are Good, Actually

Have you ever encountered someone who argues by pointing out logical fallacies? Ad hominem this. Appeal to authority that. “You really should learn basic logic, bro”. “In fact, you should pay for my online course in logic where I walk you through brilliant insights like that A = A and that two contradictory things cannot both be true at the same time”. If only it were that easy. While I’ve always intuitively understood that this approach to reasoning is somehow wrong, no one has been able to point out exactly why. Why is the logicbro wrong, and is there any scenario under which logical fallacies are acceptable? I have come to believe that certain logical fallacies have a valid use, and are reasonable tools for discerning the truth in scenarios where we have insufficient information to resolve a problem.

Appeal To Authority

Imagine for a second that you are attending a debate on quantum physics. On stage, two men argue. One is a harvard physics professor with a long, flowing white beard. The other is a cretin dressed in blue jean slacks, buck teeth hurling spittle onto the stage whenever he smacks his lips. The harvard professor claims that “quantum entanglement is caused by vacuum fluctuations in the Higgs Field” (or something or other you don't understand). Cletus then vehemently disagrees with the professor and provides a complicated argument for why the professor must be wrong. Suddenly, a hidden soldier steps out of the shadows, nudges the barrel of a rifle into your back, and forces you to judge who is correct. Who do you pick?

If you have any common sense and want to avoid getting shot, you pick the professor. This is actually a fact of some philosophical depth. Like most people, you probably don't understand the first thing about quantum physics. You are therefore unable to judge this specific controversy on the merits of the case. Moreover, even if you tried to figure out who is correct on the facts, you run a significant risk of misinterpreting something important and choosing wrong. The backup approach is therefore to just choose the man with the more adequate credentials, because he is more likely to be correct on the subject matter of his expertise. So you might reason as follows: "I cannot decide whether quantum entanglement is caused by vacuum fluctuations, since I don't have an adequate knowledge of physics. In this state of ignorance, I have a relatively low probability of figuring out who is correct by attempting to use reason. But if I choose who to trust based on credentials alone, my experience tells me I have a decent probability of being right." In this sense, choosing who to believe on credentials is entirely rational. So, crucially, going with an appeal to authority “fallacy” and judging people based on who they are rather than their arguments themselves may work out well for you in this scenario, or at least better than attempting a purely logical solution.

It’s worth picking apart why exactly this is the case. The critical reason for why the appeal to authority makes sense here is that you cannot understand the subject matter, so are unlikely to be able to logic it out. On the other hand, if you truly were an expert on quantum physics, you could accurately judge whether the professor is right. So it’s a lack of information that advantages the appeal to authority. Specifically, authority serves as a heuristic in this hypothetical. A heuristic is just a shorthand for guessing the answer to a problem (like picking the odd answer out in a multiple choice quiz), in this case, the debater’s credentials are a shorthand way of determining how likely their opinion is to be correct. We’ve discovered the key finding of this essay, which is that in scenarios where we have insufficient information, logical fallacies act like a shorthand approach (a heuristic) for judgement, and can sometimes make it more likely for us to uncover the truth.

At this point the reader will no doubt question whether the hypothetical I created has any relevance to the real world. But consider that almost every opinion you hold comes from consensus rather than logic. Pick some arbitrary controversy like whether plastic is harmful to sea turtles. You probably believe that it is, but you also likely don't have an expert-level understanding of sea turtles or statistical proof of the harm plastic causes them. So, you are ultimately trusting scientific consensus to figure it out. In turn, scientific consensus is just another authority. We believe that plastic is harmful to sea turtles, because a group of very smart and credentialed men agree that it is so, much like we believe that the Harvard physics professor is correct because he is credentialed. The point is ultimately that the process of believing authority figures is a healthy shorthand for forming opinions on topics without having to become an expert on everything. We use this appeal to authority frequently, and there is a definite benefit to doing so because authority often proves to be right. This specific fallacy is not so fallacious after all.

A group of very smart and credentialed men

Ad Hominem

A similar case can be made for rehabilitating the ad hominem. Imagine that your favorite idol (philosopher, influencer, author) turns out to be an evil criminal who steals candy from babies. You might become disillusioned with their ideas, even if those ideas are technically unrelated to their crime. Why? Well, matters of ethics are quite complex and typically lack sufficient information for a logical solution, so heuristic reasoning holds weight. One can reason that a person who engages in evil is unlikely to have correct ethical opinions overall, so while they might have some logical justification for their ideas, their actions provide stronger evidence to the contrary. The same goes for fat fitness trainers, poor wealth-gurus, rich monks and other strip-mall hypocrites who preach one thing but live another. All are worthless because their despondent lifestyle suggests a hole in their logic.

An interesting aside to briefly mention here is that modern science has generated a wealth of evidence that a person’s physical appearance, constitution, and mannerisms are predictive of certain lifestyles, which in turn might impact our judgement of their ideas. Take for example extreme obesity, which is scientifically correlated with a lack of impulse control. Trusting an extremely obese person’s opinion on virtue or abstinence might not make sense given this empirical link between their physical constitution and mindset. Another interesting trait to consider is masculinity, which correlates with testosterone levels, which in turn correlate with several behaviors and thought patterns. One can accurately make predictions about people based on how masculine their face looks, among many other physical characteristics. Obviously this approach of judging people based on what they look like is probabilistic and only has some chance of success. The value of this method is that it gives you some insight into a person when you have none, i.e. another shorthand approach for scenarios with little context or information like the appeal to authority.

Appeal To Nature

Another fallacy that turns out to be reasonable is the appeal to nature. Evolutionary theory teaches us that man has long adapted to very specific natural conditions and that their absence is generally bad for us. Incidentally in creationist philosophy the case is much the same, because God is believed to have created the world in a way that specifically suits our natural existence. It’s therefore quite obvious why unnatural environments or behaviors (e.g. long confinement in prison, social isolation, diets high in processed food, etc) have such a negative impact on us. Essentially, naked chimps are evolved for the African prairie not a concrete jungle.

Some will argue that man in his natural state is violent and does many things we find immoral, hence nature is not so good for us after all. The violence of nature is plainly apparent, but this argument misses our innate drive to return to this sort of existence, despite its warts. In fact, the psychological pressure of modern society is so great that without the nation state holding us at gunpoint some men will form cartels, murder each other, or generally regress to one caveman hitting another over the head with a rock. If high society is so alluring, why does violence return the second our final marine climbs onto the last helicopter out of Kabul? If anything, we seem to crave the violence of nature judging by how hard it is for civilization to beat that tendency out of us. History shows that we’ve had to forcibly drag man out of nature, kicking and screaming, and that even then, this process is barely complete and has a strong tendency to undo itself without careful management.

Here’s another thought: take a wild animal; shove it in a confined space, feed it a processed diet, expose it to the constant gawking of wandering eyes and grubby fists pressed against the glass of its enclosure. Watch it wither and die. Why is this fact so obvious at the zoo but a fallacy when it comes to man? Is man really so unique that torture for animals is bliss for man?

Obviously, the point is not that there is a one to one correspondence between what is natural and what is good. As in the previous examples, I’m talking about what we should assume by default. The correct default assumption is that the unnatural is also likely harmful to us, unless reasonable evidence can be provided to the contrary, because evolution (or God) has created an interdependence between man and nature. As before, an appeal to nature is shorthand reasoning for situations in which the evidence is inconclusive.

Barbarism undefeated (US retreat from Afghanistan)

Conclusion, Limitations Of Fallacious Reasoning

We have now briefly shown how a handful of logical fallacies are not actually fallacious and instead represent a form of logical shorthand for judging complicated matters in the absence of sufficient information. So … should we just trust the experts, judge people based on what they look like, and return to a state of nature? Well no, even fallacious reasoning runs into certain limitations. Specifically, if these fallacies are shorthand for a stronger argument, then we should ditch that shorthand the second compelling information actually becomes available. If we no longer need an expert to explain the basics of a discipline to us, or we find that the experts in a field are misguided and untrustworthy, then we ought to ditch authority and return to reason. If we can determine that someone is making a particularly good point despite the wrinkles on their face or in their personality, we should look past our initial impression and hear them out. And if it can be shown scientifically that a specific practice is not harmful despite being unnatural, then we should trust that proof over our initial skepticism. Shorthand ought to lose to a full proof once one is presented.

This also establishes how and why we should employ these fallacies in our reasoning. We should use them exclusively to make reasonable guesses about topics we cannot yet logic through. For example, we might assume that the scientific consensus on a topic is correct (an appeal to authority) until we learn enough about the discipline to form a reasoned, heterodox view. Remember that intellectual humility nudges us to be realistic about our degree of knowledge on random topics, and particularly on controversial or complex issues. It’s better to acknowledge that you are a novice and own up to a use of shorthand rather than to assume that you, yes you, are the one to instantly solve some thousand-year dilemma via simple logic. Essentially, use these fallacies wisely and only when appropriate, and set them aside when you learn of a genuine argument.

I suppose that this conclusion can be summarized with an analogy to the Dunning-Krueger effect. Stupid people will employ logical fallacies because they don’t know any better. The middling sort will reject these fallacies because they were taught to hate them. However, the truly enlightened will recognize that every fallacy contains a kernel of reason and they will remember that deep down, fallacies are only hated because they speak the truth.