An increasingly large part of the population in the West identifies as religious Nones. Contrary to what might be assumed, most of them are not outright atheists. They reject traditional religion, but many pursue different forms of spirituality, and many entertain supernatural ideas. This Element concerns the worldview of these 'semi-secular' Nones. When asked about whether they believe in God, they usually provide answers like 'Perhaps not God per se, but I do believe in something'. Belief in 'somethin' is the ontological cornerstone of many Nones' worldviews. The authors reconstruct it as the view 'Somethingism'. They assess Somethingism by inquiring how well it stands up to the epistemic challenge of being true to the demands of reason. They also assess it by exploring how it manages the existential challenge of providing comfort and guidance in this life, and its ability to align us with any transcendent reality there might be. This title is also available as open access on Cambridge Core.