Hans Peter Broedel
By way of conclusion, I would like to offer you a final example of the close interdependence of medieval science, technology and religion: the Cathedral.
Cathedrals are my favorite memorial of medieval Europe—soaring high into the air, their huge vaults seemingly almost weightless upon thin stone pillars, glowing with the radiant light of countless panes of brilliantly colored glass: cathedrals are wonder incarnate, and one of humanity’s enduring artistic masterpieces.
To build these architectural marvels required enormous skill and enormous resources, but build them they did. In France alone, during the high middle ages medieval people constructed more than eighty cathedrals and hundreds of large stone churches in the new “Gothic” style.1 These depended upon three technological innovations.2
- The first, the rib vault, probably arose in Islamic Spain through incremental improvements upon the Roman barrel vault, but where the vault ribs (the arches that support the roof and ceiling) in the old style ran parallel to one another, in a rib vault they run diagonally, crisscrossing, making the structure stronger while at the same time permitting thinner ribs and supporting pillars. (insert a link)
- The second was the pointed arch and also an Islamic invention. In all arches, the force of supported weight is projected both vertically downward and horizontally outwards, but it is the outward push that poses the greatest problem because without the help of the ground the walls and pillars must support the weight of the vault Pointed arches direct a much greater proportion of force vertically, so they can be taller and slimmer, and yet stronger. (insert a link)
- The final innovation was the flying buttress, perhaps adapted from buttresses used in the walls of fortresses. The flying buttress was an external brace that supported the pillars upon which the arches of the vault rested. This meant that the walls between the pillars supported almost no load at all and could be quite thin, or even replaced entirely with windows of glass. (insert a link)
These technologies enabled the Gothic cathedral’s construction, but do not explain why they were built in the first place. For that, we need to understand the meaning of light in the middle ages.
Light has long been a metaphor for the divine, as, for example, it appears in the writing of St. Augustine and John the Evangelist (see John 1.5 ). Yet due to the influence of a late antique theologian, now known to scholars by the tongue-twisting name of Dionysius the Pseudo-Areopagite, light was much more than a metaphor to medieval scholars. Dionysius argued that physical light was a visible expression of God, a reflection of that divine light that bound the cosmos together and joined it with the being of God.3 To medieval theologians, steeped in Aristotle, this was an appealing notion, because it meant that their earthly senses were capable of experiencing the divine, not through some singular mir