Physiological Self-Regulation: The Eighteenth-Century Modernization of the Human Body

Long neglected in the history of ideas, one leading science in the age of Enlightenment was physiology. It was an area for tremendous innovation, not only affecting medical-anthropological knowledge in the narrow sense but also the age’s cognitive and social doctrine. This, in turn, left an influence on the great complex of subject- and system-centered philosophies unfolding in Germany around 1800. For the drastic changes unfolding in the previous decades with regard to doctrines of the human body proceeded on various levels and involved disparate realms, in a modern scientific landscape gaining contour at that time. The following discussion represents an effort to describe some of the main features of this landscape.¹

I. The Turn from Humoral Pathology

Whatever differing notions were at work in individual cases, traditional European medicine generally conceived of the human body as a receptacle filled with fluids: the well-known humors. Corresponding to the body’s common division into three zones (head, torso, and lower body) with three correlative realms of the soul, these fluids were differentiated according to rank. The finest, most noble substances were in the head, where they sustained the body’s intellectual functions; the breast-area was the seat of the vital functions (breathing and circulation) and their spiritual correlatives; in the lower region, carefully separated from the higher zones by the diaphragm, the animal desires ruled, their vehicle being the impure fluids of the liver, digestive tract, and sex. But despite this hierarchy, the relationship between spiritus and humores was marked by active transformation. They could turn into each other and—in case of disease—replace each other as well; they mutually communicated shortage and superfluity, since the corporeal innards were largely conceived amorphously and basically obeyed hydraulic-quantitative laws.

This inner permeability corresponded to an outer openness. Through exhalations and inhalations, the individual body was not only tied to other bodies but to the entire cosmos. This system of cosmological correspondence is most manifest in the doctrine of temperaments, whose classificatory framework brought together the influence of stars, seasons, and elements with the physiological features of each individual corporeal soul.

If we were to anachronistically read the modern opposition between the self and what is alien to it back into pre-modern Europe, then we could describe that period’s prevailing view of the body as heteronomous in a complex way. This is at the very least the case on a level of practical power, for rule was grounded on power of disposition over the body. Juridically liable persons were not considered apart from their naked physical vulnerability—something we see most clearly in the realm of criminal law.² Corporeal punishment was the standard counterpart of a legal offence, hence an integral element of governmental-administrative power.

It is important to note that corporeality was not simply defined by what was “alien” to it in the age’s network of social power-relations, but rather in relation to the basic dimensions of space and time. This was the case for the temporality of human existence in that every individual was perceived as merely a scarcely noticeable link in an eternal genealogical chain, his existence an interim, birth a continuation and transmission of life instead of a new beginning.³ When it came to the spatial dimension, the human body could only exist as one element in a network of sympathetic linkages and dependencies beyond its own borders.⁴ Until far into the early modern period, its place was firmly fixed in the cosmos by magia naturalis. The principle of similitude tied each of its parts with other elements of the spiritual and creaturely world. The doctrine of the humors, of the corporeal fluids, which offered a synoptic view of astral, animalistic, and characterological elemental orders, simply excluded the idea of a subjective identity with oneself.⁵

The same can be said in relation to physiology of the senses. According to antique pneumatology, sensory perception did not take place on the bodily surface (for instance, on the eye’s retina) but rather emerged through the...