Philosophic Book Turned Thin

Last night, I made a dream about philosophy:

I couldn’t remember how this dream began but I think it is related with the book “Sophie’s World” by Jostein Gaarder, I am reading it these days. What I can remember after wake up is that I put a heavy philosophic book or some kind of philosophic dictionary into my pocket and went to an open-air street market for inexpensive or secondhand articles with my friends. When I walked in the crowd, suddenly, I felt my arm was hit by a guy walked by me with a smile. I thought that is a thief, and I check my pocket for something been stolen at once. I found my philosophic book turned into thin, which has lost a lot of pages.

At this moment, another old man with wrinkle on his face walked by me and I subconscious realized he is a wise person or even a philosopher. So I asked him why my philosophic book turn thin, but he seemed absence of mind, I looked into his eyes that something else was making him worried. I couldn’t get the answer until his granddaughter came here (a litter girl) with crying. I didn’t heard clearly what they were talking about, but I noticed that their eyes on a shabby house which maybe dismantled, I guess. They were so desperate because they became homeless.

Now, I understand the reason of their pain in heart. But why my philosophic book turned thin and what clues told me that old man is a sage?