Adaptation is the “simplest and gentlest of all laws” (GA12:248/OWL 128), which governs how entities become manifest as what they are – namely, it ordains that something’s essence is disclosed in terms of that to which it is adapted or well-suited. The German word “Ereignis,” translated here as “adaptation,” is built on the root verb eignen sich – to be apt or suitable for something (see section 3 below). That to which things are adapted need not itself be an entity – indeed, the principal cases of interest to Heidegger are Dasein’s adaptation to being, the nothing, to death and the world (none of which, of course, are entities).