I think everyone is mixing up belief with truth, Just because a belief is untrue does not make it irrational. We think, think, feel and express in an artistic manner not a scientific one. One says God and and points to a painting on the wall of an old man with a grey beard. He may believe that is God because of our limited or creative way of thinking and explaining things but it is by no means irrational, the truth may be far from that painting but still hold much of what is meaningful to our experience. What is more a more rational explanation of a chair a drawing, a poem, a mathematical equation or directions to assemble the chair. It depends on your perspective and these are all beliefs none more rational than the other. The truth lies somewhere else beyond . We all draw the line somewhere, if I believe that your building is on fire right now thats irrational because its based on nothing but thats turning the conversation into some existential rubbish.