CS Lewis is best known for his "Chronicles of Narnia" and his books of Christian apologetics, such as: "Mere Christianity" and "The Screwtape Letters". However, he was also an academic: a fellow and tutor of Magdalen College, Oxford, and professor of Medieval and Renaissance Literature at Cambridge University. This is his last academic book, published the year after he died.
Lewis here outlines (what we would call) the Medieval Geocentric Cosmology and Natural History (especially Human Nature). This is very different from our modern scientific theories of Cosmology and Biology. Lewis' point is that, if we do not understand the worldview of medieval writers, we cannot fully understand their writings.
Two points made by Lewis are worth noting. It is sometimes thought by moderns that the medieval universe was small and closed in. In fact the Earth was, by cosmic standards, a point; it had no measurable size. The Sun and stars were known to be larger than the Earth. The stars were known to be far more than a hundred million miles away. (This is small by modern standards, the Sun being about 93 million miles distant, but can any of us claim that we truly appreciate the difference between a hundred million miles and the six million million miles of a Light Year?)
A second point is that it is often claimed that when Copernicus put the Sun rather than the Earth at the centre of the Universe, this was a demotion for the Earth. The Medievals believed that the Heavens were the place of purity, made of Quintessence, a fifth element not found on Earth. The Earth itself was the "offscourings" of the Universe, the dregs, the "cosmic dust-bin" (p 63). In making the Earth one of the planets, Copernicus could be regarded as promoting the Earth into the Heavens, surrounded by the Aether, the place of purity.
If you have read CS Lewis' novel "Out of the Silent Planet" you will know that in the final chapter (Chapter 22) Lewis refers to a twelfth century writer, Bernardus Silvestris. It turns out that Bernardus was a real person and Lewis refers to his writings on a number of occasions. What is more, Bernardus does use the word "Oyarses" from which Lewis got the "Oyarsa" of Mars (Green and Hooper, "CS Lewis, a Biography" chapter 7)
Lewis says that the Medieval Model of the Universe delights him but he does not recommend a return to the old Model. What we should remember is that our Model of the Universe is still a Model and is likely to be superseded in its turn. In fact our modern Cosmology depends on two theories (Quantum Theory and General Relativity) that are supported by every experimental and observational test and yet are thought to be incompatible with each other. That is why modern cosmologists are trying to supersede our current Model with their search for a Theory of Everything or a Theory of Quantum Gravity.
This is one of Lewis's more difficult-to-find academic works. However, if you find it and read it, you will not be disappointed. I read the book on my own initiative while taking a master's class in Medieval literature. I probably learned as much from his book as I did from the whole class, and it opened up countless delightful possibilities for future enquiry. It also gave me a great idea for my final paper, which I'd been lacking the inspiration to write. What's more, this work is still respected in academia. Recently I was reading a Cambridge thesis on the subject of early printing (The Printing Revolution in Early Modern Europe by Elizabeth L. Eisenstein) and came across a quote from _The Discarded Image_ (an uncited quote, which was annoying, but that's another story). Eisenstein quotes most authors in order to disagree with them, but she didn't disagree with Lewis (added to him, qualified him, but didn't disagree), which was unusual. Lewis was one of the few authors in her field that Eisenstein did not attack! I also passed _The Discarded Image_ along to one of my previous college professors and he decided to include ideas from it in his Survey of English Literature course. If you want to know how medieval men and women saw their world - their belief in supernatural beings intermediate between angels and devils, their admiration for all kinds of organization, their heavy reliance on the snippet of Plato to which they had access-read this book. You will never see the Middle Ages quite the same way again.
I've recently finished the McGrath Biography of C.S. Lewis, and ordered several books to read/re-read: I have to agree with the 'blurb' writer: this is the best book he wrote. In it, he wears his huge learning lightly, distilling his knowledge and wisdom into crystal-clear drops. Having read it the once, I shall soon have to read it again - for information, for understanding, and for delight.
Most people think of C S Lewis as the author of the Narnia books, a science fiction trilogy, and book of popular Christian apologetics. He was also an expert on literature, particularly of the medieval and Elizabethan periods. This book aims to set out the view of the cosmos and of humanity which lies behind much medieval literature. (Despite its subtitle, the book is essentially about the medieval period, not the Renaissance.) It succeeds brilliantly.
The main focus is on cosmology and medieval beliefs about supernatural beings inhabiting the Earth and the universe, and on the constituents which make up the human soul and body. Towards the end there is a discussion of medieval attitudes to history and to originality in literature (with the stress on the way most authors saw themselves as building on their predecessors - just as most medieval cathedrals developed over a long period of time).
The book steers largely clear of considering religion and the influence of Christianity. Instead it emphasises a Model which thinkers and scientists developed for the universe and humans' place in it.
There is much reference to literature, and the book remains extremely useful background material for anyone interested in medieval literature. But it also has much to offer those interested in history and in the development of scientific thought.
C S Lewis does a successful demolition job on the idea that medieval thinkers were flat-earthers - they knew the Earth was a sphere - or unscientific in their approach: they thought scientifically, even if some of their science has proved erroneous; they experimented, and used sophisticated maths; they knew that the universe was vast and people just specks in it; they had a broad grasp of things like gravity; but many of them also took too much on trust statements about strange creatures in some Greek and Roman writings.
If I have a criticism of the book, it is that for the most part it presents a single coherent Model. I question whether medieval thinking was as uniform as C S Lewis tends to imply. I believe that there were some broad features of the Model which most thinkers and writers accepted, but that there was quite a lot of variety in people's beliefs about many aspects of how the universe operated and how humans were constituted (just as today there are, for example, major differences of opinion between cosmologists): and of course thinking evolved over time.
The broad features of the Model C S Lewis presents were widely accepted for centuries, and some aspects lasted well beyond the Copernican revolution and even beyond Newton. That is a salutary lesson for us today. Who knows whether the model of the universe that scientists generally accept now will have to give way to a substantially different model at some point in the future?
The book is meticulously researched and deeply scholarly. It does away with the current PC line that the Christian tradition can be invalidated by a clever question from a boy of 7. This is because it demonstrates that a mystical tradition like Christianity has to be seen within a context which determines the questions you ask and the presuppositions with which you understand the answers. If your reality is determined by a belief in secular materialism and in purely quantitative methods of establishing the truth, the statements of a mystical theology will have absolutely no meaning for you. An understanding of the mediaeval cosmos is a good place to start for anyone wondering which of these two world views are the most exciting, the most life-filled, and the one most likely to lead them to a world they can believe in and delight in.
This book was mentioned by Fred Gettings in his book on the medieval symbolism of the Tarot. It is probably a set book for students of English Language but I would follow Gettings and recommend it to esotericals. He explains subjects like the four humours in relation to personality and how the universe looked to people before Copernicus. He looks at the classics as they were known before the renaissance and how astrology and church doctrine had to rub along together.Anyone who wants to study traditional astrogy or magic will find this a useful way of making the necessary alterations to our modern "rational" worldview.