Deliberate, large-scale interventions in the Earth’s climate system, collectively known as “geoengineering”, are increasingly being proposed to counteract the worst effects of global warming. Public and scholarly controversies have ensued due to the high risks and high uncertainties that characterise these novel technologies. For all that, geoengineering is currently being evaluated at the highest levels of governance, and a full-scale review by the United Nations is ongoing. To enrich the understanding of geoengineering, the present work reviews the metaphysics behind the main arguments in favour and against geoengineering. Based on the varied conceptions of humans, nature, knowledge, and technical systems, which support their appraisals, proponents and opponents of climate engineering are grouped into four ideal-types: homo naturans, homo faber, homo sapiens, and anthropo-not-seen. In addition to the pro-against geoengineering fissure, a second one is identified: transcendental-instrumental metaphysics.