When Scout falls out of the tire in "To Kill a Mockingbird,"why does she feel that Boo Radley is still alive?

Besides the "audio evidence" of Boo's laughter from inside the house at the end of Chapter 4, we readers are led to believe that Scout has an innate sense of Boo Radley's presence in her vicinity. When the children are playing, she resists saying anything about Radley's existence because she doesn't want to be accused of having "Hot Steams," or believing in apparitions. Along and along, however, readers are shown that Scout has an underlying knowledge of Boo's presence, as she refuses to partake in the play that the children manufacture about the Radleys, among other things.

At the story's end, we witness the culmination of Scout's intangible relationship with Boo Radley when she is mysteriously rescued from the wicked Mr. Ewell.