Why does SQ underline the supernatural in in regard to the book given to Zhang Liang by the old wise man?

 In the last paragraph of Ch. 55 about Zhang Liang on p. 114, the SQ remarks that although most scholars deny the existence of ghosts and spirits, they accept that of unusual beings. He says that when Gao Zu found himself in difficulty, Zhang Liang ‘always found a way out” thanks to the book given to him by the unknown old man. On the other hand, the beginning of the chapter (p. 99 through 101) builds a narrative that although not excluding the supernatural, brings the mind into a different, more reflective direction. One reads on p. 100 that the old man gave Z. Liang a book (The Grand Duke’s Art of War), which he studied on his own. That is, the things that he learned from the book imply effort to study, reflect on ideas, and apply them, so later Z. Liang became fit to “foresee the difficult while it was still easy and brought forth great things from small” (p. 99t). On p. 101 t one reads that because Gao Zu admired the book and its strategies, Z. Liang decided to follow him. The baffling part here is that on the one hand, the whole of SQ’s work invites the reader to reflect about the moral lessons offered by the deeds of men who influenced Chine history and their consequences, and to learn from them along the lines of personal instruction and character cultivation. The beginning of the chapter (p. 99 through 101) supports this reflective mood. On the other hand, in his remarks in the last paragraph of the chapter (p. 114) that suggest that the event with the wise old man giving Z. Liang the book was the work of Heaven, this comes in a way as a reflection-inhibiting element, right at the place when the reflective reader would need inspiration to end the chapter, sit back, and reflect on the lessons that can be learned from it. As pointed above, the existence of the supernatural element in the beginning of Z. Liang’s journey does not exclude his personal strive to study and learn from the book on his own, yet the placement of this indication at the end of the chapter seems to inhibit the same type of effort on the part of the reader, supported by SQ so far in his book.