A natural resource is not given, but depends on human knowledge for its exploitation. Thus a 'unit of resource' is, to a significant degree, a 'unit of meaning', and education is potentially important not only for the use of resources but also for their creation. The paper draws on poststructuralism to confirm the intuition that it would be misleading to conceive of 'units' of meaning. However, it is commonly acceptable to conceive of 'units' of resource, as in much discussion around sustainability; but, if the latter concept is suspect, then so is the former. The error seems to arise from the assumption of identifiable points in space-time, already problematised by quantum mechanics and poststructuralism. Conceiving of 'now' as a moving in and with time, rather than as a point in time, human survival is construed as an ongoing process of meaning-making constrained though not determined by the carrying capacity of the planet. The Second Nature conception of John McDowell is critiqued with respect to this.