Closures as a Precondition of Life, Agency, and Semiosis

The goal of this paper is to explain the evolution of life through the evolution of cellular and supra-cellular closures, two distinct ways of strict delimitation against the surroundings. Such closures are a necessary precondition of organisation, semiosis, and agency. We argue that in addition to the basic, first-order, cellular closures, which have been in existence without interruption since the dawn of life, there also exist second-order closures (cell communities), which are dynamic and often formed ad hoc. Moreover, a living entity may belong simultaneously to different kinds of such second-order closures. It is these second-order closures which organise cellular (and higher-order) communities and form the core of the bonds that hold the biosphere together. In second-order closures, there exist countless crisscrossing pathways leading to manifold interpretations of particular situations. We provide examples of such relationships and point to an elaborate network connecting all denizens of the biosphere.