The end of the second chapter (pp. 110-114) is dedicated to the establishment of the validity of whatever has been said by the Buddha through the validity (inferentially established) of what he said in regard to the Four Noble Truths. But how does one know that a reliable speaker of X (=the four noble truths) will be reliable also in a fully different sphere? One does not expect an expert of anatomy to be reliable in regard to codicology! Even the fact that the Buddha must be compassionate, since he communicated to us the four noble truths, is not enough, because he could have been compassionate and willing to help, but still not an expert in a certain area.