Abstract

A physiological function can be described as a cycle based on a cusp bifurcation set in catastrophe theory. This cycle involves four phases that are successively developed along a functional potential, which is used to perform a given physiological act. The work we present is firstly based on a detailed study of the global function of vision, which covers a vast field extending from the molecular to cerebral scale. We then present other examples of generalised functions by expanding the frame of reference, from the scale of an organ to the scale of a whole organism with predation function, and to the scale of a social group with crisis management. We observed that the criteria remain the same, whether the function is considered on the scale of a cell membrane or a group of individuals organised into a cohort. Moreover, a so-called generalised function can be broken down into simpler sub-functions, each phase of the initial function containing the physiological act of each sub-function. It seems thus that a fractal extension may characterise the four-cusp spiral. This spiral is increasingly large as the types of sub-functions are multiplied. In functions relative to sociological science, such as crisis management, which are not natural but built and designed by humans, close attention must be paid to following the rules of these generalised biological functions