Nir Eyal argues that beliefs are tools, not immutable facts, and that we can choose new ones if they don't serve us. He explains that motivation is a triangle of behavior, benefit, and belief, with belief being the crucial element for persistence. The conversation covers how to challenge limiting beliefs through a 'turnaround' exercise, the destructive nature of rumination versus scheduled 'worry time,' and how to rebuild belief after failure by setting checkpoints and ensuring continued learning. Eyal discusses how beliefs can physically affect the body, citing the nocebo effect and cases of neuroplastic pain, and offers a three-step process to overcome it. He also introduces the concept of 'learned hopefulness' as an antidote to the brain's default state of helplessness, and shares his 'placebo prayer' practice as a method for personal change. The key takeaway is that by auditing and intentionally changing our beliefs, we can increase our agency and shape our reality.