Question of the Strange and Queerness That I Cannot Understand (Wk)

In The Strangeness of Science by Richard Dawkins, is found: .

When the narrator reads aloud about the recall an experience of ones childhood. Ones able to see, smell, heard, or feel; as if ones were once really there. "The bombshell," then gets dropped into our ears, exclaims "you weren't there, not a single atom that is in your body today was there when that even took place; matter flows from place to place and momentarily comes together to be you; whatever you are there for you were not the stuff of which you were made." This concept is "important" for us understand says the reader.
-Question: How does the matter of energy takes turns or be exactly us? And how is it that feel that familiarity? Does this relate to time transporting, if there is really such thing as time transporting? Does this mean it is possible for us to be at two or more places at once and can possibly take different forms all at the same time?

In the lecture it also mentions that the middle world; us, that resides in this world has a solid brain so we can define solids and not walk through walls. Yet, next line, he mentions, "insects are reverse."
-Questions: Does it mean insects does not have a solid brain? Come on. It can't be implying that insects can pass through solids; if I am missing out, someone can tell me that they actually witness them passing through rocks and the walls?