Inner cleansing … the senses … training and adaptation … care of the body surfaces … place, space and order … pollution … tools, adornments and body-art … water, springs and stoves.

Dirt is only matter out-of-place and is neither ‘good’ nor ‘bad’. Nature does not care what we think, or how we respond, to matter in all its forms. But as a species we do care, very deeply, about our own survival. A dense mass of human history clusters around the belief that dirt is ‘bad’, and that dirt-removal (cleansing) is always ‘good’. The old Anglo-Saxon word ‘clean’ was used in a wide variety of situations: it was often blatantly human-centred or self-serving in a way we might call ‘moral’; but it was also used more objectively as a technical term, to measure or judge material things relative to other things. It was thoroughly comprehensive, and unquestioned.

Preceding all human cultural history however – certainly before any human history of personal hygiene – were billions of years of wholly a-moral species development. The exact date one enters this endless time-line is almost irrelevant; what we are really looking for are the time-spans or periods when things speed up, which in the case of homo sapiens was somewhere between c.100,000-25,0000 BCE, followed by another burst of development after c.5000 BCE. Throughout this long period of animal species development, all of our persistent, over-riding, and highly demanding bio-physical needs were evolving and adapting, and providing the basic infrastructure for the later, very human-centred, psychology, technology and sociology of cleanliness.

It is difficult not to use ancient language when describing the egotistical processes of human physiology – routinely described as the ‘fight’ for life – and in particular, our endless battle against poisonous dirt. Much of this battle is carried out below the level of consciousness. Most of the time our old animal bodies are in a constant state of defence and renewal, but we feel or know nothing about it; and the processes are virtually unstoppable. We can no more stop evacuating than we can stop eating or breathing – stale breath, of course, is also an expellation of waste matter. Ancient scientists were strongly focussed on the detailed technology of these supposedly poisonous bodily ‘evacuations’ and modern science also uses similarly careful technical terminology when describing bodily ‘variation’, ‘elimination’, ‘toxicity’ or ‘waste products’. In either language, old or new, inner (and outer) bodily ‘cleansing’ is ultimately connected to the more profound principle of ‘wholesomeness’ within the general system of homeostasis that balances and sustains all bodily functions.