In this paper, I examine the variety of hierarchical structures that biological systems have been able to construe by changing the extension of their borders. By acting as a space/time structure separating the inside from the outside, a border allows one to be distinguished from otherness and to perceive as meaningful any difference from the external environment. Based on these premises, I then discuss the role these borders have played in the course of evolution for allowing both eukaryotic cells to become functionally differentiated and multi-cellular organisms be equipped with a bodily basis for cognition.