Naturalism, as exemplified in the podcast episodes provided, is a perspective that emphasizes the understanding of the natural world through scientific inquiry and empirical observation, rather than appealing to supernatural or religious explanations.

The episodes touch on various aspects of naturalism, such as John Muir's journey and environmental challenges, the implications of a naturalistic worldview for consciousness and our place in the universe, and the spiritual connection between humans and the natural world.

Naturalism as a philosophical and literary movement is also highlighted, with episodes discussing topics like the political use of time and narratives of progress, as well as the broader environmental literature and naturalism in the arts.