Here, at TeensReadToo, is a terrific short review of Headlong that makes the extremely terrific point, to wit: When we say we have changed “because” something else happened, what does that actually mean?

The reviewer notes that a reader “has to wonder if the changes Lily goes through happened because of Hazel or simply coincided with her arrival.”

So, when we jump, are we ever pushed (or invited, or prodded, or whatever) or are we just waiting for the momentum to come along?

In real life, so much of our behavior seems predicated on forces we can’t identify, or can see only with hindsight, sometimes the longer ago, the better.