Rational discussion starts with the question "why?" or "what are your grounds for making that assertion?" Refusal to respond is proof of irrationality. A response is subject to further questioning, until the rational basis of the assertion has been shown either to exist or not to exist. The process is modeled in many of the Platonic dialogues.
Shane Mage
"When we read on a printed page the doctrine of Pythagoras that all things are made of numbers, it seems mystical, mystifying, even downright silly.
When we read on a computer screen the doctrine of Pythagoras that all things are made of numbers, it seems self-evidently true." (N. Weiner)