  Although worlds (networks of involvements, what Heidegger sometimes calls Reality) are culturally relative phenomena, Heidegger occasionally seems to suggest that nature, as it is in itself, is not. Thus, on the one hand, nature may be discovered as ready-to-hand equipment: the “wood is a forest of timber, the mountain is a quarry of rock; the river is water-power, the wind is wind ‘in the sails’ ” (Being and Time 15: 100). Under these circumstances, nature is revealed in certain culturally specific forms determined by our socially conditioned patterns of skilled practical activity. On the other hand, when nature is discovered as present-at-hand, by say science, its intelligibility has an essentially cross-cultural character. Indeed, Heidegger often seems to hold the largely commonsense view that there are culture-independent causal properties of nature which explain why it is that you can make missiles out of rocks or branches, but not out of air or water. Science can tell us both what those causal properties are, and how the underlying causal processes work. Such properties and processes are what Heidegger calls the Real, and he comments: “[the] fact that Reality [intelligibility] is ontologically grounded in the Being of Dasein does not signify that only when Dasein exists and as long as Dasein exists can the Real [e.g., nature as revealed by science] be as that which in itself it is” (Being and Time, 43: 255). 