"These types are admittedly one sided demonstrations of Nature, but they are an educational experience for the man who refuses to be blinded by the intellectual mode of the day. In their own way, men with such an attitude are educators and promoters of culture. Their life teaches more than their words. From their lives, and not the least from what is just their greatest fault, viz. their incommunicability, we may understand one of the greatest errors of our civilization, that is, the superstitious belief in statement and presentation, the immoderate overprizing of instruction by means of word and method."
This is in relation to both Si and Ni types, introverted irrationality.