Asymmetric Weapons are weapons that are inherently more powerful to one side of a conflict than another - Unlike a symmetric weapon, which can used as effectively by both sides. The term was originally introduced by Scott Alexander in his essay Guided By The Beauty Of Our Weapons, where he argued that truth, facts, and logic are asymmetric weapons for "the good guys":
Logical debate has one advantage over narrative, rhetoric, and violence: it’s an asymmetric weapon. That is, it’s a weapon which is stronger in the hands of the good guys than in the hands of the bad guys. In ideal conditions (which may or may not ever happen in real life) – the kind of conditions where everyone is charitable and intelligent and wise – the good guys will be able to present stronger evidence, cite more experts, and invoke more compelling moral principles. The whole point of logic is that, when done right, it can only prove things that are true.
In the same essay he gave rhetoric and violence as examples of symmetric weapons....