Living systems - autonomous unities
Abstract
The question which is never entirely resolved is: what is life? Biology, claims to stand for the study of life and living things, yet we would say that it cannot make a thoroughly clear distinction between living and non living, except in some very obvious cases. There are textbook definitions, of course, based on certain notable properties such as the ability to metabolize or reproduce, but these are arbitrary. If we are familiar with the characteristics of a particular animal or plant, we know enough to be able to pronounce that it is dead when certain internal and external behaviours are no longer evident. Even this has difficulties - such as revealed in the arguments about whether to switch off a human life support system or not. When you find a squishy object on the seashore, can you be sure if it is alive or dead - or never living? The same dilemma confronts medical scientists and microbiologists trying to decide, for example, whether viruses are living, or quasi living, or intermittently living, or what.