If you believe you can, you probably can. If you believe you won't, you most assuredly won't. Belief is the ignition switch that gets you off the launching pad.

The quote argues that belief functions as a practical catalyst: confidence does not guarantee success, but disbelief reliably prevents it by discouraging effort, persistence, and risk-taking. Waitley’s contrast (“probably can” vs. “most assuredly won’t”) highlights asymmetry—optimistic belief increases the odds by enabling action, while pessimistic belief becomes self-fulfilling through avoidance and premature quitting. The “ignition switch” metaphor suggests belief is not the whole engine (skills, planning, opportunity still matter) but the initiating condition that allows those resources to be used. In this sense, the statement is less about magical thinking than about the psychology of agency: what you expect shapes what you attempt, and what you attempt shapes what becomes possible.