Abstract and Keywords
This chapter focusses on Roger Bacon’s discourse on experimental science. On 22 June 1266, Bacon received a letter stamped with the papal seal of Clement IV instructing him to send the Pope ‘writings and remedies for current conditions ... not withstanding any prohibitions from his order’. This instruction faced him with the task of summarizing some thirty years of work and thought. Bacon’s response included Opus Majus, ‘the greater work’, and possibly Opus Minus, ‘the lesser work’. In his discourse, Bacon argued that a ‘philosophical chancellor’ could organize science and the pursuit of technology for the benefit of the Christian world. He dispatched the great work to the Pope in 1267, presumably with the hope that Clement might take on this role.
On the 22nd of June 1266 Roger Bacon was sent a letter stamped with the papal seal of Clement IV (a contemporary copy of which still exists in the Vatican archive), instructing him to send the Pope ‘writings and remedies for current conditions . . . not withstanding any prohibitions from his order’. Bacon had appealed to the then cardinal Guy de Foulques three years earlier and had received an encouraging response. This instruction, coming after Guy’s surprise elevation to the papacy, now faced him with the task of summarizing some 30 years of work and thought.
The Great Work
His initial response was the Opus Majus (the greater work), but while this was being copied he seems to have added first the Opus Minus (the lesser work), and then a third, Opus Tertium. At least the first two volumes of this trilogy were sent to the Pope together with two enclosures: a map of the world and a lens.
The significance of these enclosures would not at first have been apparent. The Opus Majus begins with a general consideration of the importance of wisdom in such things as the governance of the Church, the conversion of the heathen, and the repression of evil. In asking why wisdom is hard to obtain, Bacon identifies four causes that obstruct it: subjection to unworthy authority, the influence of habit, popular prejudice, and a false conceit of our own wisdom. ‘Wise men’, he argues, ‘. . . feel they are more lacking than fools’, and for this reason are ‘humbly disposed to receive instruction from another’.1 This, in particular, includes Greek science. After reviewing the history of the Church’s relationship with Greek thinkers Bacon goes on in the second part to a more general consideration of the relationship of philosophy and theology.
His starting point (like that of his predecessors) is that since all wisdom comes from God it cannot be inconsistent with (p.168) itself: ‘truth wherever found is thought to belong to Christ’.2 There may, however, be differences of focus, so that in some instances scripture may describe a phenomenon and reveal its final cause ‘from which the efficient cause can be investigated’.3 An example of this was the rainbow whose significance is described in Scripture, but whose physical cause ‘was not clearly understood by the philosophers’4 and which, like Robert Grosseteste, he was very interested in trying to work out.
It was very helpful to Bacon’s case to argue, as had many Christian authors, that Greek philosophy had ultimately derived (via the Chaldeans and Egyptians) from the Hebrew patriarchs, but this does not lead him to gloss over its distinctive character. His conclusion is rather that ‘philosophy is . . . the unfolding of the divine wisdom by learning and art’.5 ‘There are’, he points out, ‘many common rational truths which any wise man would easily accept from another, although he might be ignorant of them himself’.6 Therefore, Christians ought ‘not only to collect the statements of philosophers in regard to divine truths, but should advance far beyond to a point where the power of philosophy as a whole may be complete’.7 The philosophizing Christian ‘can unite many authorities and various reasons and very many opinions’ and this must be undertaken not merely ‘to complete philosophy’ but because ‘all truth’ is ‘divine truth’.8
With this programme established, Bacon then proceeded to describe two principal tools which were needed to pursue it. The first of these was a knowledge of languages, the second was a knowledge of mathematics (a concept whose full significance would become apparent in future centuries) [Fig. 20.1] (see Chapter Forty-Nine).
The study of language, Bacon argues in Part III, is critical to give us accurate translations both of the Greek and Arabic philosophical texts and of the texts of Scripture (not to mention such practical things as ‘intercourse with foreign nations’). Mathematics, he argues in Part IV, is ‘the gate and key’9 to all other sciences. ‘The fundamental principles of demonstration’ cannot be made clear ‘except in the realm of mathematics . . . Therefore of necessity logic depends on mathematics’.10 The dependence of astronomy on mathematics ‘was obvious’, as was the study of optics [Fig. 20.2]. ‘The things of this world’, he insists, ‘cannot be made known without a knowledge of mathematics’.11 It was necessary for astrology (then considered a science) and for such practical matters in the life of the Church as (p.169) the reform of the calendar. It was also needed for the accurate determination of longitude and latitude that was necessary if the Church was to fulfil its worldwide mission (hence a chapter on geography and the inclusion of a map of the world).
Part V concentrates exclusively on optics, the science with which Bacon was particularly fascinated (hence the inclusion of the lens). He is keen to point out the benefits that might flow from it and argues, like Grosseteste, that it could ‘from an incredible distance’ allow us to ‘see the smallest letters’ and ‘might cause the sun and moon to descend in appearance’.12 Not only this but a new kind of ‘geometrical figuring’ could give such a reality to religious art that ‘the evil of the world would be destroyed in a flood of grace’.13 Giotto’s frescoes in the basilica of St Francis, executed 50 years later, might be considered the first installment of this promise.
His focus nonetheless is on the means by which this science can be advanced. Thus, he starts with a detailed examination of the physical structure of the eye, and goes on to describe some of his own experiments with reflection and refraction. This then leads him in Part VI to a more general reflection on the nature of experimental science.
Experience, Bacon suggests, comes in two kinds. There is the internal experience of things spiritual which ‘comes from grace’, and there is that which ‘is gained through our external senses’. We gain our experience of things that are in the heavens ‘by instruments made for the purpose’, and of things that do not belong in our part of the world ‘through other scientists who have had experience of them’.14 It is with the latter that he is principally concerned. The distinguishing characteristic of what he calls ‘the science of experiment’—De Scientia Experimentali—is that ‘it investigates by experiment the . . . conclusions’ of other sciences.15 To illustrate this he returns to the example of the rainbow.
While the natural philosopher, he argues, comes up with theories or ‘judgements’ about phenomena like rainbows and haloes, ‘experimental science attests them’.16 He first of all looks for visible objects in which the colours of the rainbow appear in the same order, and finds ‘this same peculiarity in crystalline stones correctly shaped and in other transparent stones’17 as well as when ‘the solar rays penetrate drops . . . in water falling from the wheels of a mill and likewise when one sees on a summer morning the drops of dew on the grass in the meadow’.18 Armed with these ‘terrestrial facts’ the experimenter looks at ‘those phenomena that occur in the heavens’ using ‘the recquired instrument’.19
Bacon then proceeds to describe how using his own measurements (made presumably with an astrolabe) ‘the experimenter . . . taking the altitude of the sun and of the rainbow above the horizon will find that the final altitude at which the rainbow can appear above the horizon is 42 degrees and this is the maximum elevation of the rainbow’.20
Bacon was the first person to discover this. He went on to argue that each raindrop in the bow worked as a spherical mirror, producing because of their proximity a continuous image. He was aware that his account of how the rainbow was produced was far from satisfactory ‘because I have not yet made all the experiments that are necessary’21 and was convinced that ‘experiments on a large scale and by various necessary means are recquired’22 (this was, in fact, achieved some 50 years later by a Dominican friar, Theodric of Freiburg, who demonstrated using spherical globes filled with water how primary and (p.171) secondary rainbows are produced by double refraction within a raindrop). His point is that he is ‘proceeding . . . not by the method of compiling what has been written on the subject’ because ‘experiment not reasoning determines the conclusion in these matters’ and he ends with ‘a plea for the study of science’.23
Bacon concludes his discourse on experimental science by arguing that a ‘philosophical chancellor’ could organize science and the pursuit of technology for the benefit of the Christian world. He dispatched the great work to the Pope in 1267, presumably with the hope that Clement might take on this role. It was not to be. By the end of 1268 news had spread throughout Europe that Clement had died in November.
Bacon’s fate after the death of his patron is unclear. He wrote a ‘collected study of philosophy’ which contains a bitter attack on the corruption of every aspect of church and society. This may explain why in The Chronicle of the 24 ministers general of the Franciscans written a century later, he is named as a master of theology imprisoned for ‘suspect novelties’.
In 1274 Bonaventura was succeeded as head of the Franciscans by Girolam D’Ascoli, who is known to have imprisoned a group of suspect friars who remained in confinement until released by his more merciful successor, Raymond de Gaufredi, in 1290. There is no direct contemporary evidence that Bacon was imprisoned, but given that he seems to have written nothing further until 1292 when he appears to have been back in the Franciscan abbey in Oxford, it would fit with the facts.
While Bacon’s larger plans for the development of what he called experimental science may have failed, two of his ideas found strong echoes among his successors in both Oxford and Paris. The first of these was his emphasis on the role of mathematics as the key to all other sciences. The second was his conviction that the laws of reflection and refraction were a part of what he describes as leges communes nature—the universal laws of nature.
(1) R. Bacon, The Opus Majus of Roger Bacon (1928), Part I, Chapter X, 25.
(2) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter V, 43.
(3) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter VIII, 51.
(4) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter VIII, 51.
(5) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter XIV, 65.
(6) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter XIX, 73.
(7) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter XIX, 73.
(8) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter XIX, 74.
(9) R. Bacon, The Opus Majus of Roger Bacon, Part IV, Chapter I, 116.
(10) R. Bacon, The Opus Majus of Roger Bacon, Part IV, Chapter II, 120.
(11) R. Bacon, The Opus Majus of Roger Bacon, Part IV, Chapter III, 128.
(12) R. Bacon, The Opus Majus of Roger Bacon, Part V, Chapter IV, 582.
(13) R. Bacon, The Opus Majus of Roger Bacon (1897), 219.
(14) R. Bacon, The Opus Majus of Roger Bacon, Part VI, Chapter I, 585.
(15) R. Bacon, The Opus Majus of Roger Bacon, Part VI, Chapter II, 587.
(16) R. Bacon, The Opus Majus of Roger Bacon, Part VI, Chapter II, 588.
(17) R. Bacon, The Opus Majus of Roger Bacon, Part VI, Chapter II, 588.
(18) R. Bacon, The Opus Majus of Roger Bacon, Part VI, Chapter IV, 589.
(19) R. Bacon, The Opus Majus of Roger Bacon, Part VI, Chapter IV, 590.
(20) R. Bacon, The Opus Majus of Roger Bacon, Part VI, Chapter IV, 592.
(21) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter XII, 615.
(22) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter XII, 615.
(23) R. Bacon, The Opus Majus of Roger Bacon, Part II, Chapter XII, 615.