Don't underestimate the tremendous motivational force of challenging someone to produce facts to try and prove you wrong. Most people like to be right and will expend at least some effort to support their point.
If you can get someone to do this, you'll benefit in multiple ways:
- You'll better understand counter arguments against your point of view.
- There's the opportunity to learn more about your topic from a different perspective.
- You might discover you are actually wrong and be able to correct your own misunderstanding of the issue in a lower risk situation.