Medieval Lessons for the Modern Science/Religion Debate

I have been asked to write a book chapter on this topic following a workshop in the Ordered Universe interdisciplinary series on medieval science. For some reason I thought that a summary might make a suitable Christmas blog post: it’s a season when we look back (a long way) into the past for strength and guidance in the here and now. 800 years back to the time of Robert Grosseteste does not seem so immense a leap right now.

A 14th century image of Robert Grosseteste as Bishop of Lincoln

A 14th century image of Robert Grosseteste as Bishop of Lincoln

Grosseteste (depicted adjacent) was a deeply scholarly man, a teacher to the Oxford Franciscans in the 1220s, and Bishop of Lincoln from 1235.  During the period from 1225 to 1235 (probably) he wrote a series of about a dozen works on scientific topics: light (De luce), colour (De colore), the rainbow (De iride – he was the first to identify refraction as the driving phenomenon of rainbows).  You can find out much more about Grosseteste and his scientific work at the ‘Ordered Universe’ blog linked above.  This is a project where we bring the skills of medieval scholars, latinists, historians, philosophers, theologians and active scientists today, all to bear on analysing these treatises, their texts, and the scientific logic within them.  It’s fascinating!

It’s also an important exercise for the themes of Faith and Wisdom in Science, because it evidences the theme of the book that science has a much longer history than we usually credit it with.  Perhaps, rather, the activity we now call ‘science’ is the name of the current chapter in a book of human engagement with nature that has many many previous chapters.  The 13th century was certainly an important one.  And not only because of the early science it contains, but also because of the theologically-derived underpinning purpose behind a human attempt to understand the physical world.  As I argue in the book, we just dont have a purpose for science today (apart possibly for a very narrow and instrumental economic one).  So mining more ancient wisdom, while not applicable immediately in our own age, is likley to be a fruitful exercise, and a fascinating one.

I think that there are five chief ways in which this 13th century master, and his intellectual and theological milieu, can assist in escaping our current impasse. I have called these: (1) the disruption of damaging myths, (2) the long history of science, (3) a cultural narrative for science, (4) a unified vision and (5) a relational and incarnational metaphysics. We next discuss each thread in a little more detail.


1 Disruption of Damaging Myths

As has already been noted, a common meta-narrative of the history of science in both public media and (at the least) school education, is that nothing remotely resembling science existed before the early modern period (or the late 16th century). According to this story, before Galileo and Newton any philosophy of the natural world was clouded with magic, alchemy, superstition, and – worse of all – the dogma of theology[1]. There are other sub-narratives that emerge – that the scientific method is entirely modern, that medieval thinkers’ chief goal was in any case to recapitulate the thoughts of the classical philosophers and not to move beyond them, that the medieval church repeatedly suppressed innovative thinking in general, and that ‘theology’ and ‘science’ were indistinguishable in the medieval world of scholasticism. Grosseteste’s scientific corpus serves as an immediate gust of fresh air to remove such flimsy cobwebs of reconstructed history.

The shortest of the scientific treatises, the De colore (on colour) is enough on its own to remove credence in such a fiction. As I and others had explored in depth elsewhere[2], the De colore represents a piece of work that a modern scientist would recognise as being in continuity with, though naturally distant from, questions posed and methods pursued today. Grosseteste does not allegorise or mystify colour; he does not accord any supernatural powers of transformation to it; he writes no explicitly theological material in his treatment at any point. On the contrary he treats colour as a perceived property of the natural world.

Color est lux incoporata in perspicuo – the opening line of the treatise – introduces the conjecture that colour is an emergent property of light and matter. He then identifies the different colours of objects as betraying the activity of different lights (characterised by the variation of two quantities of greatness – multa/pauca – and clarity – clara/obscura within materials characterised along a third dimension of purity – purum/impurum). There is to this day an unsolved problem in cognitive psychology of the apparent ordering, continuity and perceptive proximity of colours [3]. Grosseteste prepares the ground for an approach to this issue by creating an abstract theatre of colour space. He is also working in a highly mathematical way (though this has not always been recognised in the secondary literature on the De colore). The numbers of possible colours and their contingencies are calculated in terms of the combinatorics of his three bipolar qualities. Never explicit, but strikingly obvious to mathematically equipped readers of his and Aristotle’s theories of colour, is that in developing a three-dimensional colour space between the opposing poles of black and white, he is going far beyond the Philosopher.  Grosseteste insists that per experimentum (whether by thought or in action is beside the point here) one only reaches all possible colours by the variation of three independent quantities. The treatise does not represent a mere recapitulation of ancient thought, but goes far beyond it in imaginative theory as well as in mathematical complexity and observational relationship.

Within this short text of 400 Latin words we find, in this reading, a recognisably scientific approach to the mathematical modelling of an observed physical phenomenon. Naturally it is of its own time, not of ours – we now understand the origin of the three-dimensionality of colour to have its origins in the three types of photosensitive cone cells in the human retina, not directly in the properties of light or materials. But the core characteristic of science is not to be found in the answers it holds pro tem, but in the questions it poses, the way it goes about answering them and in the direction of intellectual travel. In this sense Grosseteste is in continuity with questions and methods in colour science today. If that were not true, it would be hard to explain why a team of scientists encountering this work in detail, and the related treatise on the rainbow, the De iride, were immediately inspired to create some new science. They recast the physical optics of the rainbow, and the perceptual framework of human colour vision, to show that even in contemporary terms, Grosseteste was correct in asserting that colour space can be both spanned and mapped by ‘the space of all possible rainbows’[5]. Remarkably, this analytic work, required originally to establish whether the colour space of the De colore was indeed equivalent to the perceptual space used today, led to the discovery of a new mapping for the space in which the coordinate system is inspired by the spectral characteristics of rainbows.


2. A long History of Science

A second aspect of our deconstruction of the ‘modern science’ myth requires some comment: it is one thing to show that Grosseteste and his contemporaries were working in a potential logical continuity with science today; to show that this is also an actual historical continuity with it is another. It may never be possible to retrace the full pattern of reception of his scientific corpus. These treatises, remarkable as they are, are not as widely referred to as the Hexaemeron and Psalm commentaries, for example. Yet nearly two generations after their probable first writing, Roger Bacon had grounds to acclaim Grosseteste as the greatest mathematical genius of the century. The conceptual continuity of his geometric optics and work on the rainbow, with those of Bacon, Theodoric of Freiburg, the Prague school of the 15th century, and onwards to Newton’s own Optics, strongly suggests that historical transmission of his science accompanies the conceptual possibility.

But whatever the detail and extent of their later adoption and development, Grosseteste’s scientific works are testament to the longer continuity of a human intellectual story that we now call ‘science’, but which went by other names in earlier ages. It might better be termed ‘natural philosophy’ in the 18th and 19th centuries or even ‘natural wisdom’ in antiquity. A vital thread is that of a developing story – natural philosophers are consciously drawing from ideas of the past, but building on and correcting them. Our evolving understanding of nature has a history, with a more occluded past, a present mixture of partial understanding and of open questions, and a hoped-for future of clearer insight.

If the 13th century is marked by the dawn of the first concepts in experimental method, then in Grosseteste it also represents a clear new departure in the ubiquitous application of mathematical thought to natural science. From our modern perspective, it is hard to imagine an intellectual milieu in which this would not seem natural. But that is because we do not share the same sharp dualism of the perfect and imperfect inherited philosophically from Plato and cosmologically from Aristotle. Grosseteste himself comments on the Posterior Analytics that we are able to do with mathematics that which God is able to do with physics – that is to deduce conclusions from axioms within a closed system. We do have access to the fundamental axioms of mathematics, but only the Creator has that access in regard to nature. Our task is to arrive at those axioms inductively from observations of their consequences. Such human predicament of incompleteness is a consequence of our dwelling in the sublunary world of imperfection. Now, while is it natural that (perfect) mathematics applies to the structure and motion of the (perfected) spheres above that of the moon, it is by no means clear that it will be as commensurate with the (imperfect) realm of the elements. To assay a mathematical analysis of sublunary nature is therefore not only a critical, but a bold, step. Yet it is one that Grosseteste takes in each of his scientific treatises. In spite of the unavailability of advanced algebraic notation of any kind, he is able to compute, for example, abstract vectors combinatorially in his three-dimensional colour space. Perhaps more impressive is the continuation of his discussion of colour in the De iride, in which he considers the conceptual space of all possible rainbows. Though not immediately apparent as such, this high degree of abstract and structured thinking is highly mathematical.  In re-thinking Aristotle in critical ways, and in advancing mathematical tools to conceptualise the structures that lie behind the superficial perception of phenomena such as colour, Grosseteste partakes in both the reception and advancement of a much longer story of science than typically frames discussions of religion and science today.


3. A Cultural Narrative for Science

Perhaps the most striking contrast between Grosseteste’s intellectual world and ours can be found in our differing teleology. Cultural narratives are able to generate purpose, or equally, to proclaim purposelessness. So, while he knows why he is exploring the natural world, and develops a strong sense of purpose in doing so, we have in our own time lost any such propelling meta-narrative. In late modernism a faint echo of a human reason that we do science remained, but only in an instrumental narrative of national economic prosperity. In a post-modern atmosphere of suspicion around all overarching stories, that too (possibly healthily) has withered.

There are both simple and more sophisticated strands within Grosseteste’s motivations to engage in natural science. On a delightfully childlike level, at one point in his commentaries on the Psalms, he reflects that, if the Bible chooses to convey truth to its readers through the illustrations of natural objects (trees, clouds, falling leaves etc.) then it behoves us to discover as much as we are able concerning them, simply in order that we might better understand the scriptures. An application of this very direct thinking appears in an explanatory note accompanying his edition of John Damascene’s De Fide Orthodoxa. Two chapters in the earliest manuscripts at his disposal concerned scientific topics that ostensibly had no contact with the theological substance of the work as a whole. Earlier editors had sometimes omitted them for that reason. But Grosseteste reinstates both, explaining that:

“These two chapters, namely the 24th about seas and the 25th about winds, are omitted in some Greek manuscripts; perhaps because they did not seem to contain a theological subject. But according to truly wise men, every notice of truth is useful in the explanation and understanding of theology.”

We see immediately the impressively connected philosophy of knowledge that drives his studies. Although he is perfectly able to distinguish theology and science (again, there was no age – certainly not the 13th century – in which they were ‘indistinguishable’), he takes the two as mutually dependent in at least illustrative ways. He maintains a clear distinction between theological and scientific writing, but within an implicit and deep connectivity. So although we find no explicit theological introductions or conclusions to the scientific works, this is because their theological task speaks for itself. For an explanation of deeper connection between the silent theological framing of his natural philosophy, and the science itself, we need to turn to the philosophical works. In the Commentary on the Posterior Analytics (of Aristotle) Grosseteste places a more sophisticated theological philosophy of science within the overarching Christian narrative of Creation, Fall and Redemption. Employing a Boethian metaphor for the effect of the Fall on the higher intellectual and spiritual powers (in descending hierarchy those of understanding, memory, imagination) as a ‘lulling to sleep’ by the weight of fallen flesh, he maintains that the lower faculties, including critically the senses, are less affected by fallen human nature than the higher. Human understanding (aspectus) is now inseparable from human emotion and loves (affectus); the inward turning of the latter now dulls the former. However, there is an avenue of hope that the once-fallen higher faculties might be re-awakened: engaging the affectus, through the still-operable lower senses, in the created external things of nature allows it to be met by a remainder (vestigium) of other, outer light. So a process of re-illumination can begin once more with the lowest faculties and successively re-enlighten the higher:

“Since sense perception, the weakest of all human powers, apprehending only corruptible individual things, survives, imagination stands, memory stands, and finally understanding, which is the noblest of human powers capable of apprehending the incorruptible, universal, first essences, stands!”

Human engagement with the external world through the senses, necessary because of our fallen nature, becomes a participation in the theological project of salvation. Furthermore, the reason that this is possible is because this relationship with the created world is also the nexus at which the human seeking is met by divine illumination. As a central example, the ‘physics of light’ grounded in the cosmogony of the De luce informs a ‘metaphysics of light’ as a vehicle to become a ‘theology of light’.  The teleological – purposeful –  employment of scientific investigation as an instrument of human participation in a reversal of the effects of sin in the fall, is an idea that itself reawakens in the early modern period, especially (but by no means exclusively) in Francis Bacon [4].


4. A Unified Vision

Reading Grosseteste from a scientific perspective excites resonances with a class of thinkers for whom a unified map of the world has the highest value. Einstein is perhaps the most celebrated modern example. The prime motivation for his Nobel Prizewinning work on the photoelectric effect was not a central attack on that problem – it is in any case a corollary to the paper [5] – but a desire to develop a thermodynamic account of light. Similarly, relativity arises, not from a direct analysis of time and motion, but from an attempt to overcome an uncomfortable incommensurability between late 19th century electromagnetism and mechanics.

A similar passion for a single vision has already emerged in our examination of the De colore and De iride – taken together with the De luce these works replace a fragmented universe of coloured objects by a unified theory of the activity of light within body to generate the phenomenon of material extension that in turn produces the phenomenon of colour. Furthermore, the abstract geometry of colour itself works as a unifying mathematical framework in all of its occurrences, arising from the product of internal properties of materials and of light.

Perhaps more remarkable is the completely original unification that Grosseteste makes, at least by implication, in the De luce, of the superlunary and sublunary cosmic regions. For Aristotle, as we have seen, the universe contains two incommensurate and separate realms in which, for all time, both nature and physics are different. The imperfect spheres of the elements sustain vertical motion, mixing, disease, while above the moon all matter is perfect, crystalline and all motion circular. There is not even a temporal connection between the two regions, since this separation has been the case for all time. The cosmogony of the De luce is not only a remarkable application of Aristotelian physics taken in a critical vein to overthrow an Aristotelian cosmos without beginning, nor is it just an impressively clever theory of origins. It also demonstrates how the same creative force of light (in its two forms of lux and lumen) and its action of rarefaction and compression on matter, can give rise to both superlunary and sublunary regions within a single process of structure development, itself determined by a uniform set of properties. Grosseteste explains that the inward progression of lumen, together with its successive perfection of the spheres, is eventually weakened through distance from the firmament and through the work it needs to do in passing through all the underlying spheres. Below the orbit of the Moon, there is insufficient power within the field of lumen to form any further perfected spheres, so what materials remain – the elements – are compacted but left unperfected. Today we would term this process a ‘symmetry breaking’: the operations of a uniform physical process on a system that originally possesses a state of symmetry, breaks that symmetry by creating two regions in different states. A detailed computational study of the physics in De luce has confirmed that such a programme can be taken further than the text alone is able to, using tools unavailable before the invention of the calculus [6], but translating only Grosseteste’s own physics into the computational mathematics.


5. A Relational and Incarnational Metaphysics

There is another purpose evident in Grosseteste’s thought behind the re-engagement of the human mind with the inner structures of the cosmos, one that is independent from the post-lapsarian invitation to re-awaken fallen minds. This second strand is important to him, for one of his great theological questions concerns an alternative history – one in which there is no Fall from grace. In the De cessation legalium he asks famously An Deus esset homo etiam si non esset lapsus homo? The question of the incarnation in such an unfallen world has corollaries – in particular would we be doing ‘science’ in such a world? Is there, in other words, a motivation for natural philosophy that goes beyond the restoration of a mind once perceiving nature clearly, but now clouded and dulled? Although the text does not address this question directly, it points in very strong directions that parallel Grosseteste’s conclusion that there would indeed have been an incarnation of God in an unfallen world, and that his relationship with human and non-human creation maintains a directional narrative even without its disastrous first turn.

Grosseteste points out, once again driven by the primacy of his unifying principle of light, that the human body communicates with all corporeal natures (‘communicat in natura’) because of the way light is incorporated into all elements by its reflection from the heavenly bodies. All of the rational soul of humans, the sensitive souls of animals and the vegetative souls of plants share both the same indwelling of constitutive light, and the composition of the elements. He entertains a very early insight into the material way in which humankind is, literally, earthed into creation. An even more impressive account of such material connectedness across the cosmos is found towards the end of the De luce, and is worth quoting in full:


And it is clear that every higher body in respect of the luminosity begotten from it is the species and perfection of the following body. And just as unity is potentially every following number, so the first body by the multiplication of its luminosity is every following body. Earth, in contrast, is all higher bodies by the collection in it of the higher luminosities. Thus, the poets call it “Pan” (that is,“All”) and it is named Cybele as if cubele from the cube (that is, from solidity); because it is the most compressed and dense of all bodies, it is Cybele and mother of all the gods, for although all higher luminosities are brought together [in earth], they have not come forth in it through their operations, but it is possible that the luminosity of any celestial sphere you please be drawn out from earth into act and operation, and so from earth, as if from a kind of mother, any god will be procreated.

A modern version of this sentiment was made famous by the scientist and communicator Carl Sagan, drawing a material communication between human and cosmic materiality not from light, but from the atomic generative properties of stars:

“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star-stuff.”

For both writers there are real, material reasons that connect us to even the most distant objects in the universe. The difference is in the material detail: Grosseteste deduces them from the structuring properties of light, Sagan from the unique environments within the cores of stars, where alone heavy elements can be manufactured. In spite of the efforts of thinking such as this, almost poetic in the connective and emotive force of its idea, the deeply relational cultural context that it suggests for science has not taken root.


The Lessons

Transforming these themes into needful narratives for a healthy science today needs the refractive process of theology in context.  But there are living themes that do offer a healing path to the current troubled story of science. The long story of natural wisdom, a high expectation of human ability and responsibility, a balance of practical an intellectual wisdom, the enduring of difficulty, an accommodation with uncertainly, a celebration of the question, and the exercise of love – these are some of the lessons we can begin to draw from a deep engagement with medieval science. They are far from irrelevant to our time. Very much more than a fascinating period in the early history of science, the 13th century and its thinkers, of whom Grosseteste is the prime example, speak with wisdom we urgently need to rediscover.


[1] R Numbers (ed) Galileo Goes to Jail and other Myths about Science and Religion (2010) Harvard University Press

[2] Greti Dinkova-Bruun, Giles E.M. Gasper, Michael Huxtable, Tom C.B. McLeish, Cecilia Panti and Hannah Smithson, “Dimensions of Colour: Robert Grosseteste’s De Colore; Edition, Translation and Interdisciplinary Analysis, (2013) Durham Medieval and Renaissance Texts

[3] Wuerger, SM , Maloney, LT and Krauskopf, J (1995) Vision Research, 35 827-835.

[4] Peter Harrison, (2007) The Fall of Man and the Foundations of Science, Cambridge

[5] A. Einstein (1905) Annalen der Physik 17 (6): 132–148.

[6] R G Bower et al., (2014) Proc Roy Soc A, 470, 20140025

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