I understood rationality here is used to describe the kind of participating in the discussion which is dedicated to establishing objective truth. Rationalizing,

I understood rationality here is used to describe the kind of participating in the discussion which is dedicated to establishing objective truth. Rationalizing, on the other hand, is something completely different even if it makes sense from the point of view of your interest. An example: a businessman may have a stake in the project and so publicly state to the effect he believes the project will succeed. The project actually is failing but he is to gain from extending the perception of success. He may be rationally taking care for his financials but to the public, he is dishonest, rationalizing and being objectively irrational given the clear facts that oppose his public statements.