How the Universe Really Works
Most of us have heard of the Four Elements - Earth, Water, Air, and Fire - and probably believe that the mediaeval philosophers thought of these as the basis of everything that existed in the material world, in the same way that we think of sub-atomic particles as the basis of our own universe.
But that’s not quite right. Mediaeval philosophers had another level of reality just as modern physicists have quantum theory, which goes deeper than the classic sub-atomic model of reality. Earth, Water, Air, and Fire were produced by combining truly elemental substances, the Four Contraries: Hot, Cold, Moist, and Dry (Hot and Dry for Fire, Hot and Moist for Air, Cold and Moist for Water, Cold and Dry for Earth). Combining these Contraries within the human body produced the four Humours, which in turn created an individual’s basic nature depending on the proportion of each which was present in that person’s make-up.
Most of us probably also believe that people in the Middle Ages thought that the world was flat. This is another myth: they knew that it was a sphere. (The idea that they considered that the earth flat originated in the nineteenth century.) According to mediaeval thinking, the globe of the earth had two polar zones, both uninhabitable due to cold, and two temperate zones, with an equator around the middle, uninhabitable due to heat. This hot zone, in fact, formed an impenetrable barrier, so that no human being could ever reach the southern hemisphere. But that hemisphere was not uninhabited: the Antipodeans (‘those with their feet opposed’) lived there. Nor were they ‘upside-down’, because it was recognised that ‘down’ really means ‘toward the centre of the earth’
According to Cicero’s Republic, in the Northern Hemisphere, where human beings lived, were several great land masses: Europe, Africa, and Asia, divided by four great north-south running rivers.
Mediaeval astronomers also knew that the Earth was larger than the Moon, but smaller than the Sun. The entire universe, however, dwarfed the Earth in size. These notions parallel our own; but whereas we think of Space as empty and infinite, mediaeval thinkers believed it to be a series of concentric spheres: the first seven spheres were those of the seven planets, namely the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn. Beyond Saturn was the sphere of the fixed stars, the Stellatum; outside that was the largest object in the universe, the sphere called the Primum Mobile. Outside that, there was no space at all, just ‘pure light, intellectual light, full of love (Dante, Paradiso, 30.38). As c. S. Lewis explains in his last book, The Discarded Image:
You must go out on a starry night and walk about for half an hour trying to see the sky in terms of the old cosmology. Remember that you now have an absolute Up and Down. The Earth is really the centre, really the lowest place; movement to it from whatever direction is downward movement. As a modern, you locate the stars at a great distance. For distance you must now substitute that very special, and far less abstract, sort of distance which we call height; height, which speaks immediately to our muscles and nerves. The Medieval Model is vertiginous. And… the medieval universe, while unimaginably large, was also unambiguously finite. And one unexpected result of this is to make the smallness of Earth more vividly felt. In our universe she is small, no doubt; but so are the galaxies, so is everything – and so what? But in theirs there was an absolute standard of comparison. The furthest sphere, Dante’s maggior corpo is, quite simply, the largest object in existence. The word ‘small’ applied to Earth thus takes on a far more absolute significance. Again, because the medieval universe is finite, it has a shape, the perfect spherical shape, containing within itself an ordered variety. Hence to look out on the night sky with modern eyes is like looking out over a sea that fades away into mist, or looking about one in a trackless forest – trees forever and no horizon. To look up at the towering medieval universe is much more like looking at a great building. The ‘space’ of modern astronomy may arouse terror, or bewilderment or vague reverie; the spheres of the old present us with an object in which the mind can rest, overwhelming in its greatness but satisfying in its harmony.
In this vast but enclosed cosmos, the main source of light was the Sun: even starlight was reflected sunlight. Shadows created the only darkness. As the Sun rotated around the Earth, the Earth’s shadow stretched out toward the spheres. The night sky was dark, therefore, because we were looking up at it through a shadow.
The really important difference between this universe and ours was what made it move: in modern terms, the motion of the stars and planets stems from an original ‘Big Bang’ and from an invisible force, gravity. But in the Middle Ages it was believed that all the motion of the spheres originated at the outermost edge with the Primum Mobile or ‘First Movable’. What made that move? The Primum Mobile moved because it had sympathy - love - for God.
In fact each celestial sphere moved because of its love for God and by the influence of the other spheres: the Primum Mobile moved rapidly, even though it was huge, and this generated the motion of the Stellatum in which the stars were embedded, thus causing the movement of the sphere of Saturn and so on. Thus implied that the spheres, far from being vast inanimate objects, possessed some kind of living quality - and this is in fact what was believed: each sphere was the abode of an angelic-like being of god-like strength and power called an Intelligence. In fact, these were the Christianized versions of the Pagan planetary gods, Mercury, Venus, Mars and so forth.
Why was this motion considered to be a perfect circle? As Lewis explained, ‘The nearest approach to the divine and perfect ubiquity that the spheres can attain is the swiftest and most regular possible movement, in the most perfect form, which is circular.’
He went on to evoke the imaginative quality of such a cosmos:
When the sun is up he dazzles us and we cannot see. Darkness, our own darkness, draws the veil and we catch a glimpse of the high pomps within; the vast, lighted concavity filled with music and life. And, looking in, we do not see…’the army of unalterable law’, but rather the revelry of insatiable love. We are watching the activity of creatures whose experience we can only lamely compare to that of one in the act of drinking, his thirst delighted yet not quenched.
This wasn’t just an observable dance in the Heavens, though: it had a direct bearing on events upon Earth. The Stellatum had an effect upon Saturn, Saturn upon Jupiter, Jupiter upon Mars and soon - and each had its effect upon the ‘ground’, the Earth. The sphere of the Moon, for example, disturbed the air, causing winds. Air was considered to be the medium by which all of the planets affected human affairs.
These ideas were embraced by the Christian Church rather than rejected: the idea that the planets exerted a physical influence upon events was about as close as the Middle Ages got to what we would consider to be a ‘science’. But when it came to astrological prediction of the future or astrological determinism, or the worship of the planets, the Church objected.
This cosmological system passed all the way down into an understanding of animal life, the soul, the senses and much more.
Lewis gave great weight to this Model as a tool for the imagination, and in The Discarded Image asks us to remember that all models of the universe are just that, models, not definitive realities - any model is a ‘best fit’ for observations made at that time, and, importantly, for belief systems at particular times.
No Model is a catalogue of ultimate realities, and none is a mere fantasy. Each is a serious attempt to get in all the phenomena known at a given period, and each succeeds in getting in a great many. But also, no less surely, each reflects the prevalent psychology of an age almost as much as it reflects the state of that age’s knowledge.
The book hints at a future in which our current model the universe is superseded as we discover more and more about how things really work.