 Within the category of spiritual substance More includes not just the souls of living creatures and God himself but the main intermediate causal agent of the cosmos, the Spirit of Nature (or ‘Hylarchic Principle’). Conceived as the interface between the divine and the material, the Spirit of Nature is a ‘Superintendant Cause’ which combines efficient and teleological causality to ensure the smooth-running of the universe according to God’s plan. It can also be understood as encapsulating ‘certain general Modes and Lawes of Nature’ (More, A Collection, Preface, p. xvi) since it is the Spirit of Nature that is responsible for uniting individual souls with bodies, and for ensuring the regular operation of non-animate nature. More sought, by this hypothesis, to account for phenomena that apparently defy the laws of mechanical physics (for example the inter-vortical trajectory of comets, the sympathetic vibration of strings and tidal motion). More underpinned his soul-body dualism by his theory of ‘vital congruity’ which explains soul-body interaction as a sympathetic attraction between soul and body engineered by the operation the Spirit of Nature.