I don't compulsive lying, in and of itself a very negative attribute, can be awarded to any MBTI type. I think all of us have the potential to be either very rational or equally irrational. I do believe however, that some of us are predisposed to certain ways of thinking and visa-versus. Whereas the Enneagram and the MBTI have 9 and 16 options respectively, sx/so/sp are very few to make a broad generalization concerning who is and is not rational. In addition, rationality is not analogous to instinct. They complement each other in certain people and situations, but instincts and intuition are not the mark of rational thought or behavior.