"It's also possible that he's just browsing through the contents with his Spiritual Perception and not memorizing anything at all…" Nangong Yuanfeng remarked a short moment later.
Browsing through the content and memorizing them were two entirely different concepts.
The former only required one to scan through the book with one's Spiritual Perception; there was no need to attempt to understand or absorb the contents at all. On the other hand, the latter required one to commit everything that one had seen to memory. Naturally, the level of difficulty for both feats was vastly different.
If it was just browsing through several hundred thousand books at once, he was able to do it as well.
"Let's keep watching. We'll know very soon whether he's faking it or not!" Tantai Zhenqing replied.