In this podcast episode, the hosts dive into solipsism, the philosophical notion that only one's own mind is certain to exist. They explore its historical roots in skepticism and discuss various types, such as metaphysical, epistemological, methodological, and ethical solipsism. The conversation delves into the practicality and implications of solipsism, linking it to neuroscience, AI consciousness, and mental health. Ultimately, they conclude that while solipsism is a fascinating idea, it poses significant challenges and remains unprovable. The episode also touches on related concepts like the brain-in-a-vat theory and the simulation hypothesis, making for an engaging and thought-provoking discussion.