Proceedings 11        December 1988        the Danson Room, Trinity College, Oxford,

ROBERT GROSSETESTE AND ALL THAT REVISITED: by Dr Crombie, President of the Society


Reflecting on thirty years of work in the history of science Dr Crambie recalled that in his books Augustine to Galileo (1952) and Robert Grosseteste (1953) he had challenged the compartmentalization of history in conventional categories. The ideas of Medieva1, Renaissance, Reformation. the Scientific Revolution and modern philosophy, were products of contemporary propaganda. He saw the history of science as the history of argument. This had its own developmental phases starting with the recovery of ancient forms of argument from about A.D.1000 on with assimilation and development occurring in step in essentially three stages:

1)control of argument - logical, mathematical, experimental

2)control of materials by practitioners of a  variety of arts outside the universities, etc.

3)establishment of rational experiment: combining mind and hand: the rational experimenter = the rational artist of scientific enquiry.

In his books he had challenged conventional historiography at what proved to be its most sensitive point: the development of experimental science in medieval Europe. Refuting the charge of anachronism he stressed the obligation to study development in the history of human thought and action as well as putting ourse1ves in the context of any given moment, awareness of a process of discovery was part of that moment. Scientific philosophers monitored the historical development of science for the purposes of science itself.

Dr Crombie next turned to specific characteristics of medieval scientific argument, particularly differences in styles of quantitative and experimental argument in the different contexts of theoretical learning and natural philosophy of the universities etc. and of the practical arts--a subject particularly appropriate to the title of the Society.

The history of western science being the history of an argument initiated by the ancient Greek philosophers, mathematicians and physicians in their search for principles at once of nature and of argument itself, it has a notable development continuity. Each generation based its work on the study of books by its predecessors. There is a progress equally in scientific knowledge and scientific argument. A subtle question is what continued and what changed through different historical contexts, in the scientific argument and in the cultural vision through which experience is mediated when education and experience itself could furnish options for a different futures. To understand the style of argument of any period or cultural group we have to become intellectual anthropologists: we have to identify the intellectual commitments involved, commitments to the conceptions of nature and of scientific enquiry presupposed: from these we try to identify the problems perceived in any historical text, the question being put to the subject matter and the acceptability of both questions and answers. We may then begin to see how explicit or implicit intellect commitments are established in advance of any inquiry and the kinds explanations that would give satisfaction because the supposedly discoverable had been discovered: how as a result certain routes were opened and others closed.

In the Middle Ages the vision of rational control was conditioned by theological predisposition and practical needs. The logical procedures whereby this habit was organized into a scientific method were drawn from Aristotle and Euclid, starting with Robert Grosseteste. The Aristotelian concept of nature and of scientific argument, and hence of Grossteste's resolution/composition method was taxonomic rather than mathematical and hence led to basic rules for reducing the ostensible causes of an effect to the one actua1 true set. The mathematization of physics was begun through Grosseteste's metaphysics and cosmology of light and geometrical optics. This led to the quantification of primary properties producing the secondary qualities of sensation. One outcome was the subordination of physical to mathematical sciences. The medieval terms experientia, experimentum and scientia experimentalis could be quite ambiguous and they represent programmes as well as realizations. There is. the test of theories and generalities by evidence, but experimental evidence came from both personal observations and from accredited authority: the logic of the argument was the same. The context of experimentation was the mathematical sciences and “natural magic.”

The analysis of the rainbow in the optics of Bacon and Vitelo was by a taxonomic definition of phenomena followed by an explanation of causes by presence:absence and correlation of degrees producing colours from red to blue by increasing refraction. In weakening the light this allowed an increasing incorporation of darkness from the medium.

Theodoric of Freiberg searched by resolution/composition with contrived experiments for the four causes. His experiments were -with models of raindrops, using spherical glass flasks of  water or crystalline balls. There were two problems: (1) the formation of the colours by each raindrop (2) how were they sent back to the eye of the observer in a definite number and in Fm arc at a definite angle. He made two discoveries (1)internal reflection and (2) relation of colours to position of drops (or model). Hence he determined the path of the rays in both primary and secondary rainbow. Comparing Theodric's achievements and limitations with those of Descartes showed that the objects of the enquiry had changed from particular causal conditions to general mathematical laws.

Natural philosophers were in general more concerned with the logic and epistemology of scientific argument than with the isolation of particular physical problems: episteme not techne. They developed a theory of evidence, criteria for causal linkages; a theory of assent and decision. This was the vision of the rational control of thought and practice. The need for the practical control of soul and body led to the further development of historical questions. Creation by God and nature was assimilated to the products of human art; clockwork analogies appear in the 14th century. New concepts of laws of nature associated with that of simulation of nature by art and that of mathematical functions evolved. The quantification in the sciences and the arts threw light on the intentions, needs and opportunities of the later Middle Ages. The use of experiment and measurement depended on the subject matter.

In natural philosophy, the primary" and classical demand was for logical precision but there was incomplete dialogue between theoretical concepts and procedures for measurement - if any at all. The context of quantification was the mathematical scientia media and it was in this context that we should understand the theoretical quantification of motion by the 14th-century schools of Oxford and Paris.

It was in the practical arts that the habit of systematic measurement arose, from practical demands of the technical arts, such as architecture, music, pharmacology, administration and commerce.

Once the true dialogue was opened between measurement and theory Episteme came to be abandoned: techne (empirical, quantified where possible concerned only with correlations) became the only science of nature available to us: this was the essential 17th century Scientific Revolution.

The secretary thanked Dr Crombie for his important paper and the meeting concluded with discussion from the floor.