Henry of Hesse (1325–1397) was one of the schoolmen of 14th Century Paris who, together with those of Merton at Oxford, began seriously—albeit by stealth—to challenge Aristotelian doctrine. As Pierre Duhem has shown, in questions such as the latitude of forms which proposed quantitative and comparative treatment of ‘virtues’ or ‘forms’ such as heat, brightness, etc. many of the concepts of early modern science developed ‘under cover’ of scholasticism. They are difficult to recognise as such since they often appear in the guise of horrendously convoluted and apparently fatuous debates on Christian virtues: Does a person’s charity increase by one charity being added to another, or by a single charity increasing, or by an infinite series of charities each of which disappears to make way for a greater?
Henry of Hesse advocated the view that the indwelling ‘occult virtues’ of things must be dispensed with altogether and that an infinite number of variations in form (intensity), combination and variable proportions of four primary qualities could account for all things in nature; thus each part of a body would have its degree of heat or cold, dryness and wetness, etc. and the whole could be described as a complex (complexio) of measurable elements in certain ratios with each other.
This not only anticipated a science for which meaning and proper place would be subordinated to position and measure (just as the mathematical treatment of movement by ‘The Calculator’ (Suisset) at Merton challenged the Aristotelian idea of moving objects having inbuilt tendencies) but also opened the possibility of infinite new, unknown combinations occuring within nature: Nature would thus no longer be a bounded, taxonomically-delimitable field but a combinatorial pool itself composed of sub-individual elements varying continuously along multiple parameters.
According to this incipient substitution (anticipative of the violence of scientific reason) of ‘functional’ criteria for the Aristotelian categories descended from banal intuition, rather than being explained by indwelling properties the nature of an object or creature would be referred to its characteristic complexio or proportional combination of elements each with a certain latitude of form (i.e. the range of heat and cold, or wet and dry, that it could withstand without being corrupted). Medicine would be the ‘art of latitudes’, the art of knowing the range (latitude) of forms (qualities) that each organ of the body could tolerate: and different creatures would be defined by their particular complexio of such latitudes:
If this doesn’t yet disabuse you of the notion that scholasticism is so much arguing about angels, read on: for this new conception had even greater psychedelic horrors to unveil…