BJ Fogg opens Tiny Habits by directly challenging the common assumption that lasting behavior change primarily requires willpower and motivation, presenting instead a behavioral design framework he's developed through years of research at Stanford's Behavior Design Lab.

Fogg's foundational critique of willpower-based approaches:

• Motivation is inherently unstable, fluctuating considerably based on mood, energy, and circumstances, making it an unreliable foundation for consistent behavior change
• Attempting to rely primarily on willpower and motivation for behavior change explains why so many habit change efforts — New Year's resolutions being a classic example — fail relatively quickly once initial motivation naturally fades
• Fogg's alternative approach focuses instead on behavioral design — deliberately structuring behaviors and environment to make desired change easier to sustain regardless of fluctuating motivation levels

This foundational reframe sets up the book's core practical framework: the "Tiny Habits" method, designed specifically to work reliably even during periods of naturally lower motivation, rather than depending on sustained high motivation throughout the change process.