The treadmill explains why chasing circumstances plateaus — pleasure adapts fast. Flourishing research targets meaning, relationships and functioning, which adapt far less readily. It's the difference between improving your conditions and changing what you're doing with them.
Side by side
Aspect
Hedonic treadmill
Flourishing
Concerns
Pleasure
Functioning and meaning
Adapts
Quickly
Slowly, if at all
Driven by
Circumstances
Engagement, purpose
Ceiling
Returns to baseline
Can genuinely shift
What each one means
Hedonic Treadmill
The hedonic treadmill is the tendency for happiness to drift back toward your personal baseline after good or bad events — so improvements deliver a smaller and shorter-lived lift than you expected.
In positive psychology, flourishing is a state of high wellbeing in which you both feel good and function well — explicitly more than simply not being unwell.