The desire machine.

The article examines the "desire machine" thought experiment, which challenges desire satisfactionist theories of well-being by imagining a device that alters a person's desires to perfectly match reality, thereby maximizing desire satisfaction but leading to apathy and diminished motivation. Unlike the "experience machine," which simulates pleasurable experiences without satisfying actual desires, the desire machine satisfies all desires but intuitively does not improve well-being. The author critiques coherence-based approaches to rational desire change and argues that a more plausible solution requires introducing a substantive, fittingness-based standard for desires—where well-being depends on how fitting (appropriate) satisfied desires are—thus necessitating a partial abandonment of pure subjectivism about well-being. This approach maintains that some desires, though satisfied, may not contribute positively to well-being if they are unfitting, explaining why entering the desire machine would not truly enhance one's well-being.