Fact: The glass is half full.
Which is the same as half empty.
The more relevant question is what conclusions do we draw from the fact?
These can be rather different depending on your take regarding half empty or half full, e.g. because they imply a different sense of urgency.
The thing is that arguing rationally based on facts can be just as frustrating as arguing emotionally when we don’t agree on the meaning of the facts. Even more so … because everyone is so deeply convinced that their take is right. After all, the facts prove them right. It really is a factual argument: “But the glass is half empty! You can’t deny that!”
Why then does the other party, based on the facts, arrive at a different conclusion? And how come they are just as convinced of their conclusion?
The problem is that facts are just facts and the argument is not about the facts. It’s about what the facts mean. It’s informed by our experiences and expectations. It’s influenced by our values and principles.
And this means, that it only masks as a rational discussion unless we agree on these things. It’s a rational discussion relative to our values and principles. Only when we agree about these will a rational argument lead to the same conclusion for all participants.
Are you clear about the values that influence the meaning of a fact to you?