How can you tell if someone is trying to defend an untenable position (e.g., the necessity of a vaccine for a flu-like virus)? They will not try to debate rationally what they think. I remember that line from the Gladiator, where a senator challenged the "emperor" by saying: "is your position so weak that it cannot stand debate?" This triggered the other guy who went on to go full-blown tyrant afterward. Funny how many people today are like this, even if they don't have the power to impose their (untenable) position...