Fallacies in Disagreement

In practice, you do not need to memorize every Latin label for bad arguments. Most fallacies fit into a few stereotypical classes.

First are relevance fallacies: arguments that distract from the claim instead of addressing it. This includes ad hominem (“you only think that because…”), appeals to authority or popularity (“the staff engineer said it” or “everyone agrees”), and whataboutism. These usually signal that the conversation has shifted from truth-seeking to status, tribe, or self-protection.

Second are evidence fallacies: weak support presented as strong support. Think hasty generalization, cherry-picking, anecdotal proof, and survivorship bias. In engineering terms, this is drawing a platform-level conclusion from one incident, one customer, or one successful rollout while ignoring the full data set.

Third are causality fallacies: mistakes about why something happened. False cause, post hoc reasoning, slippery slope, and false analogy live here. These show up when people confuse correlation with causation or assume one decision inevitably leads to disaster without intermediate reasoning.

Fourth are framing fallacies: the problem is distorted before it is even debated. Straw man, false dilemma, loaded question, equivocation, and moving the goalposts are common examples. These are especially damaging because they make smart people argue past each other while thinking they are debating the same thing.

What does this mean in real disagreements? A fallacy usually does not mean the person is stupid or malicious. It usually means they are under pressure, attached to an outcome, or reasoning too quickly. Your job is not to “win” by naming the fallacy. Your job is to restore clarity.

A good response sounds like this: “Let’s separate the claim from the person.” “What evidence would change our mind?” “Are we arguing data, causality, or tradeoffs?” “Can we restate the opposing view in a way they would agree with?”

The most useful leadership principle is simple: treat fallacies as failures of argument quality, not failures of character. When disagreements get sharper, lower the temperature and raise the standard of reasoning. That is how teams keep trust while still making hard decisions.