God's Philosophers: the Medieval World - James Hannam

who could evening and welcome to the first of the Iain Ramsey Center seminars are on science and religion for mycommerce term 2012 here at the Sutra room of Trinity College and the speaker this evening is dr. James hanim and the title of tonight's talk is God's philosophers the medieval world and the foundations of modern science that's the official title but you see there's another one here out of the chasm ancient and medieval ideas on creation just give you a bit of background to this talk and particular the light of the forthcoming presidential elections in United States it was a there was a talk that there was a speech about six months ago in which President Obama said the following he said that they laughed at Columbus when he came back and said that the world was round they laughed at Columbus when he sailed back to Europe and said that the world was round and often when I go around to schools or give talks in public I'm surprised at how much this legend that they believed that the word world was flat before Columbus voyage how much this legend has seeped into popular consciousness and so part of a general paradigm in our civilization that before the Renaissance before the voyages of discovery that they were so stupid that they thought the world was flat indeed the term medieval is quite often used as a term of intellectual abuse dr. James Hannam has done a good deal to help rectify this and to give you some of his background yet he has a physics degree from the University of Oxford a PhD in the history and philosophy of science for the University of Cambridge so a nice balance there how to say that following an illustrious tradition which includes Albert Einstein academic work is not his full-time job he's actually an accountant with Ernst and Young but he manages in his small amount of spare time to do considerable writing on pre-modern and early modern history of science and religion his first book got philosophers how the medieval world laid the foundations of modern science was published by icon in 2009 a copy here and it was shortlisted for the war Society prize for science books in 2010 dr. honam's articles have appeared in several publications including The Spectator The Mail on Sunday and history today and he's a contributor to various academic journals I should point out that it's this has been a popular book that's been well received also by academic historians and just a few days ago someone in the South America's was complimenting James remotely on the on the quality of his writing so it is it's a book that's as popular that's also being well received in by scholars so without further ado would you please welcome dr. James Hannam well thank you very much for that warm welcome I'm sorry to have deviated slightly from the official title but what I wanted to do tonight was talk not just about medieval science but also a little bit about ancient Greek science and take the opportunity to perhaps compare the two to see where they differed to see what they had in common so Greek science of course has had a very good press unlike medieval science for instance nobody ever accuses the Greeks of thinking the world was flat although of course they probably did think that prior to around 500 BC the popular image of a Greek philosopher is a guy a gal in the case of capaci oh and a recent film wandering around in togas and thinking great thoughts until all those nasty silly Christians came along and burn them all at the stake and book titles like Eureka the birth of science and a lot of books about Greek science called the first scientist or the first scientists even being written by academics it's not surprising that the belief persists that the Greeks were really very good at science and that also they understood it in much the same sort of that we do in fact in the US my book I think there's a American copy Samoan audience was given a title the genesis of science but with some unfortunate timing another book with exactly that title came out within a month but that unlike mine was singing the praises of ancient Greek science so coupled with the idea that Greece was the beginning of science as we understand it there is of course the myth that the Middle Ages were was a Dark Age for science so in this talk I want to take a critical look at the achievement of Greek science and why I think it failed to explain the world accurately and why it was that it was medieval natural philosophy which actually laid the foundation for modern science which we enjoy today now what I'm not trying to do here is denigrate ancient Greece in the Classical Renaissance sense I am a humanist in the sense that I am really rather obsessed by the ancient world and with Latin and Greek and even though I've written a book about the Middle Ages I have to admit that I very much prefer a nice sunny Greek grew into a damp and chilly medieval castle but what I would like to do is present a more balanced account of the differences and similarities between Greek and medieval science and I think we'll find that in some ways they have quite a lot in common now this is the line from the beginning of his poem Theo Jeanine unlike Homer we know a little bit about he's short he lived in central Greece and his father was a seaman who moved to Mount Helicon and he shot was a farmer probably looked after his farmers sheep and in working days his shield says how he traveled to a poetry competition at a funeral games of a king and won a tripod probably very much like this one almost certainly for the poem that these lines come from now the main source for Theogony is ancient eastern stories such as the Babylonian creation myth which begins in a very similar sort of way here he's yad is talking how out of the chasm came arable said night and from night in turn came bright day whom she bore with shared intimacy with Erebos sex coming right at the start and the Babylonian creation myth begins when the skies were above not yet named nor earth below pronounce my name actually the first one there Bogata and make a time at who bore them all had mixed their waters together then gods were born within them I think the relevance of these creation stories to later Greek science is that they make it extremely clear that the gods which the Greeks were worshipping were not the creators of the world that the Greeks lived in the the God such as Zeus Hades they were third generation gods and in fact he saw doesn't tell us where the world came from at all it just begins out of nothing really itself created there is no creator so for the Greeks creation wasn't really a religious question of course Greek religion wasn't as theological as modern religions of the book tend to be practice was considered to be much more important than exactly what you believed you had to pay the gods their due and impiety could be heavily punished but the lack of theology and a lack of thinking about the religious sources of the world meant that there was space for philosophical discussions about nature and that space was filled initially by the pre-socratic philosophers and here we have a anaxagoras who was a 6th century philosopher giving his take on where the world came from and again it's really nothingness which he imagines was the initial beginning of the world well I'm not going to talk very much about the pre-socratics largely because I'm always getting them confused and I don't even know if I'm pronouncing their names right half at the time but I think that one important idea if I can generalize about them that they had was that the universe is a cosmos a cosmos is a Greek word that simply means order and so a cosmos is an ordered thing and that means that it is in principle something which can be explained so overall the pre-socratic view of nature was that it was ordered it was rational and in the very broadest sense of the word their natural philosophy tended to be materialist now so far that's pretty similar to your typical explanations and histories of Greek science they start with the pits pre-socratics and they talk about how jolly rational they were and two excellent examples which are given to show the rational and non-religious tradition of Greek science is Hippocrates here explained to his readers that contrary to what Homer thought epilepsy madness were not Curtis from the gods they were simply any other disease a disease of the mind and also I put an illustration up of the Antikythera mechanism and which is often called a computer I wouldn't say it's really that but it is a calendrical calculating device which was discovered in a wreck off the coast of Greece in the beginning of the 20th century it's dated now to the 1st century BC it may well have powered something an armillary sphere something like this although that's difficult to tell from the remains when I took my wife to the Archaeological Museum in Athens a few years ago absolutely insisted on seeing this thing and I cannot tell you how unimpressed my wife was by it and the Greeks in fact did excel in geometry and in the creation of astronomical models their scientific methodology really typifies by Aristotle was to use a method of observation and deduction and they could be very very fine observers we have some fantastic descriptions of the prognosis of disease from Hippocrates from Galen and from the other Greek medical writers Aristotle is rightly celebrated as to pick one example for his work on embryology where he dissected chickens eggs at different states of the chicks development but there was no tradition of experiment in ancient Greece and our Stoffels method of observation and deduction could not generate useful knowledge and really the most tragic example of that is Greek medicine which was if not useless positively harmful and yet even though they went produced vast tomes of medical works you do not see anything which approaches a orderly and methodological attempt to find out which of their treatments are working the one thing they were good at because it was based on observation was diagnosis they could usually tell you pretty accurately whether or not you were going to die which was very useful for the doctors now in geometry I think they were good because deduction alone is enough in that sense in that subject to decide what is right and what is wrong you don't need an experimental sedition in order to progress in geometry so Theory generation wasn't really a problem for the Greeks they had lots of ideas but they had no method to distinguish the right theories from the wrong ones and that meant that they simply kept on arguing about the same things trees and centuries and centuries here is probably the most famous mistake made by Aristotle from his book of physics it's a fact of experience he says well yeah that the greater the weight or lightness that things have the faster they complete a given journey in accordance of the ratio and magnitudes of one to another he basically thinks that heavy objects will fall faster than light objects in proportion to their weight or David Scott an astronaut on the Apollo 15 rather dramatically Illustrated here had to go to the moon in order to finally convince a generation of schoolchildren that this isn't true when he dropped a hammer and a feather in the airless vacuum of the moon and they both hit the ground at exactly the same time now it's got to be admitted that flying to the moon is rocket science but dropping a light pebble and a big rock from your arms is not yet somehow this never took place it's true that some of our Stoffels followers like starter flam Paskus and Hipparchus did make some progress over his work up until around about 200 BC Strato for instance was able to show that air can be compressed and he was able to show that contrary to what Aristotle said a vacuum is not impossible but unfortunately he did consider continue to believe that nature abhors a vacuum he thought that a vacuum sucks because nature thinks it's such a terrible thing it trying to get rid of it of course a vacuum can't suck a vacuum does nothing because a vacuum is by definition nothing Hipparchus another Rascals followers made some interesting observations on projectile motion which is often being pointed to as one of the weakest parts of Aristotle's physics but thereafter there was very little advance in these topics a vacuum was continued to believe to be an aberration of nature Aristotle's dictum that an object that is moving requires another object to be moving it was never really challenged maggot spontaneously generate just to pick an example from natural history in rotten food Aristotle believed really because never bothered to keep the slides off so it's little a bit unfortunate that these ideas were simply never tested in the most simple sorts of ways we can find in a hundred ad here on of Alexandria collating material into handbooks or simply repeating Aristotle's dictum that heavy objects fall faster than light ones and it of course is the same here on who is so celebrated for having apparently invented the steam engine and he did invent a quite fascinating little steamed hoi but as a scientific thinker he didn't really have very much originality at all even centuries after that in the fifth and sixth century neoplatonist philosophers like simplicious are still discussing the same ideas which have been exercising Aristotle's immediate followers there simply doesn't happen to have been any kind of movement let alone progress now scientists historians of science have to be extremely careful not to be anachronistic because when we think about science today we're not usually thinking about the same subject that people in the past were thinking about but I do think it's quite important also that we don't give the Greeks credit for something which not only they didn't do but they weren't even trying to do I think it's a very important to understand that given everything we know about Greek science during thousand years of that civilization there was never going to be a Greek scientific revolution a required metaphysical experimental and progressive steps just hadn't happened and there was no sign at all that they were going to and in late antiquity Greek natural philosophy was moving further and further away from what we would recognize to be toward modern science with of course a gift a fine sight so what were the Greeks trying to do if they weren't trying to invade invent the iPhone well the Greeks natural philosophy wasn't a subject in its own right in the way that we see it science to be today philosophy as a whole had a much more basic need behind it and the creatures in his on the nature of things is actually really very clear about what he thinks natural philosophy science it's for as far as he's concerned the point of science is to stop mankind being afraid it's fear of the gods he thinks is what prevents men from living men and women from living fulfilled lives science is intended to prevent people from living in fear for Plato going back the key question of philosophy I think and I know I'm getting there's a trouble for generalizing like this was how can I be good and his natural philosophy provides him with a world where good is something which is objectively real the form of good the form of beauty and where evil has an explanation and he can answer his key question how can I be good by saying well you have to live in a world and a society which encourages us to be good and his main main leader works the Republic in the laws he tries to explain what that society would look like now for our STARTTLS keep the key question I think generalizing again is what am i for and his answer conveniently is that he's supposed to life live a life of leisure thinking great thoughts now since his interest is in purpose his natural philosophy is teleological for him nature is full of purposes there is a reason for everything but once again natural philosophy is very much a supporting act of what as a shorthand I might call ethics but by ethics I really mean rather more broadly the whole question of the meaning of life morality theology that sort of thing a good example of the way that Aristotle and Plato view science in a way we see it is their attitude towards astronomy now by the time they were writing it was already clear to Greek astronomers that the heavens were misbehaving that the way that the planets moved in the sky was not the smooth wonderful regular motions that Greeks had generally assumed our sort on Plato both know this and neither doesn't care they both continue to treat the heavens as being something of a philosophical perfection they're not really bothered about the mess of reality in his laws Aristotle in his laws Plato specifically says that you should simply ignore what the planets in the sky appear to be doing if they're going backwards and they're not moving according to the regular way that they're supposed to and you shouldn't said contemplate the perfection of the way that they're supposed to be moving moving forward to the atomists like Epicurious and our friend Lucretius here well for them the answer to the big question is life's what you make it so they're materialist natural philosophy has no purpose no objectives good and evil for them the earth that the universe is simply a dead thing in which humankind can create their own meaning so their natural philosophy is providing them with a setting in which their ethical theories make sense thus I think for almost all these Greek philosophers ethics is the priority and natural philosophy is a supporting act so in summary I don't think Greek science really succeeded according to the brutal test that we moderns might have for science of explaining how nature actually works but he did succeed spectacularly by providing a way to each individual philosophy to develop a science to undergird its own ideas science was not intended to help technology on drive progress science was intended to be just one small part of a philosophy that answered the question what am i for now of course come late antiquity there's a new religion on the Block Christianity and of course I don't think that I need to introduce Augustine or his confessions now a Gutzon I think Kant poises he saw it as a useful place to begin with Christian ideas about creation the Hebrew creation account the course in Genesis chapter one is again quite a late part of the Bible in the same way in fact that he sauces creation account it's quite a late part of Greek mythology although he's one of the earliest poems we have the the gods and heroes like Zeus and Perseus are actually found in the linear b tablets from my scene in civilization 500 years previously it's not really clear whether creation out of nothing which of course it's in Augustine's idea about where the universe came from and how God created it is a particularly Hebrew doctrine you can really interpret the beginning of Genesis in a number of different ways to deciding whether or not it supports the idea that there is something pre-existing matter which God uses to create the world that Augustine is in absolutely no doubt and I think that he's actually deliberately echoing he's got an author he really must have known because it was a very well-educated man when he deliberately places God before the abbot's and the Abbess this is interestingly enough it's the first use of that word in Christian literature so I think Augustine begins I look at Christian ideas of creation by telling us that for Christians God created the world and there was nothing prior at all and that means that for Christians unlike for many Greeks creation is most definitely a religious question now of course what Greek philosophy didn't just finish when Christianity first became the tolerated and then the state religion of the Roman Empire and we see a couple of centuries when there is a dialogue and also something of a conflict between late Greek philosophy which is dominated by an increasingly mystical Neoplatonism which attempts to try and combine Plato and Aristotle into a single philosophy which of course is actually pretty much impossible to do and the beginnings of Christian philosophy in Athens the neoplatonist had a fairly explicitly anti-christian agenda and that led to the infamous closure of the school of athens in 529 AD by the Emperor Justinian the story of the trip to Persia by the exile philosophers left led by Demetrius it's almost certainly nothing but a legend there's this delightful colorful story that the Philosopher's all themselves the persian court where they were welcomed by the great king as quite a coup but they were absolutely appalled by the sensuous and borked ways of the Persians and so as soon as they were decently able to they scampered back to the Roman Empire that's probably not a true story but it is the case that these pagan philosophers ended up in Syria probably in a city of mists abyss where they kept alive a pagan Greek philosophical tradition which lasted long enough to provide one of the roots of the Arab translation movement in the 8th century things in Alexandria weren't always very much happier than that this is a picture of Pompey's pillar in fact it was erected in 297 AD by the Emperor Diocletian in a celebration of his victory over a revolt in Alexandria has nothing to do with Pompeii at all but the reason I've got a picture of it is it stands in the ruins of the Serra p.m. and the sack of the Serapeum is one of the most notorious events in the conversion of the Roman Empire to Christianity it's also even more notorious because in the 18th century Edward Gibbon invented the myth that at the same time the Great Library of Alexandria had been housed in a temple and was lost at that time and to this day the people who don't blame Muslims for destroying a great flag view of Alexandria blame Christians personally I have my doubts that the great library in the sense that people tend to understand it is this wonderful Universal library ever existed at all but despite that event that despite the murder of Hypatia in 415 ad in a dispute of politics which seem to be pretty much par for the course in Alexandria which was certainly a brutal and dangerous place relations between Christian and pagan philosophers didn't appear to be so bad and in fact Christians became prominent members of the Alexandrian schools and the most famous of all of those is john philoponus now he appears to have done something really quite radical if you can tell from this quotation he's actually found out whether or not aristotle is right or wrong about the heavy objects and light objects falling at different speeds thing and he's noted that Aristotle is wrong can I find it absolutely incredible with all respect to the Greeks and what they were actually trying to retrieve from their science that took a thousand years for someone to do this fellow penis also bought several other fresh ideas too late Greek natural philosophy but unfortunately the Alexandrian schools didn't long last very long passed his death the Persian Empire conquered Egypt at the beginning of the seventh century occupied it for several years and no sooner had the Byzantine Romans managed to kick them out the Arabs turned up and they stayed for good and that was the end of the schools in Alexandria the Arabs moving their capital to Cairo of course so it wasn't in fact Christianity which ended the tradition of Greek natural philosophy it was the invasions from the east which led to the Byzantine Empire being under siege for much of the remaining thousand years of its life and in West things weren't looking very much better at the time cutting-edge Greek science the the philosophy is of Aristotle Plato Euclid Ptolemy they weren't available in the West because they were written in Greek and that was a language that nobody actually could read so instead Western Christians as they struggled to rebuild their civilization after the barbarian invasions had to make do with handbooks and encyclopedias like Pliny the elders natural history which were written in Latin now these are always considered by the Roman to be the sort of thing that you read before you moved on to the Greek difficult stuff so there was always a limit to the amount that Western Christians were able to achieve in natural philosophy without access to the best Greek work they also produced their own encyclopedias such as on the nature of things by Isidore of Seville and Israel here is illustrating what is one of the main purposes of natural philosophy during the early Middle Ages clergymen were very keen on it as a weapon against superstition and we have records of senior churchmen berating the common people for such superstitious behavior as believing in witches believing in demons and panicking during eclipses there are some very colorful accounts of people beating drums and dancing around trying to get the Sun to come back during the clips well one can imagine a local bishop just burying his head in his hands in despair well one advantage with these handbooks was that it meant that Western Christians at least knew what they were missing and they could get make a certain amount of progress by working through them the example of the Astronomy that the court of Charlemagne I think is a very good example because we can actually trace how the scholars and monks working in that Court were moving from the simpler texts to the more advanced texts in astronomy and we do that simply by dating the manuscripts which still survive that we can see them starting with something nice and easy like plenty or maccer basis commentary on a dream of skippy Oh which is a kind of student guide to help you understand slightly dreamy bit of Cicero and then they move on to more advanced works like Marciano's cappellas marriage of mercury and phonology which is a quite highbrow work full of some quite lowbrow jokes which covers the seven liberal arts in a reasonable amount of detail and then finally they move on to kal Sidious his commentary on Plato's Timaeus which is probably the most advanced work of astronomy that was available during the early Middle Ages then the upshot of that was at by thousand ad Western Christians had mastered the Latin literature and they knew what they were missing so they could go in search of it and the place they first found it was here Toledo in Spain which was reconquered or Concord depending on your point of view by the Spanish king the Catalan King Alfonso the fourth in 1085 and when the city was captured it was founded as magnificent libraries had all been left and fairly shortly I am an army almost of Western Christian scholars were settling in toledo toledo and star to translate all these wonderful Arab works because they found that the Arabs themselves had translated all the best ancient Greek mathematics and philosophy and that brought these important works back to light in the medieval West now it wasn't just from Arab sources that these works became available the Greek originals were brought back from Byzantium and Sicily the Fourth Crusade had at least one slightly beneficial effect by giving the Catholics control of Greece so that they could their the churchmen who they sent there to be bishops that were able to gather together a lot of manuscripts translate them and send the translations back home I believe Thomas Aquinas acquired a decent set of Greek manuscripts of translations of Aristotle from the original Greek through this source it's interesting that although we often talk about how Renaissance humanists rediscovered ancient Greek in the field of mathematics in natural philosophy they didn't really bring all that much to the party there were a few works that weren't very well known in the Middle Ages which became more popular during the 15th and 16th centuries but I think it's probably Ptolemies geography which was first translated in the early 15th century which was by far the most important Greek scientific work to be rediscovered if you like in a renaissance and I tend to think of this translation movement as an example of the ancient church Father origins philosophy that you should take gold from the Egyptians you should take useful knowledge from the infidels and it was quite all right for Christians to mine the Muslim libraries for anything which they thought was going to be useful but despite all that translation activity in the 12th century Christian natural philosophy sees a great flowering because essentially platonic rather than our stoat Lin and this I think is one of the times when Christian ideas about nature become much more developed for example we have this wonderful quotation here explaining why it is that the world that we see must have a wise creator and that led to the development of ideas about primary and secondary causes which allowed Christian to split the action of God directly which is the primary cause of everything and the secondary causes which God uses in order to allow the world to function and we also for the first time have the idea of a law of nature which in a 12th century Christian scholars developed from the Platonic idea of the world soul as the kind of guiding principle of the universe so in a 12th century the idea of the transcendence of God as creator over nature it's emphasized and nature is allowed its integrity to run along its own courses now despite the proverbial domination of natural philosophy by Aristotle in the Middle Ages I think that in fact mainstream scholasticism remained something of a hybrid because the Christian platonism of the 12th century remained within the set of assumptions that Christian scholars tended to approach Aristotelian natural philosophy and so I think they were finally able to pick up perhaps where philoponus had left off 600 years before now of course not all scholastics were bringing those platonic Christian assumptions to Aristotle and the ones that weren't are generally called of arists and they took their philosophy from a Muslim Spanish thinker who really emphasized the materialism of Plato's of Aristotle's natural philosophy they were determinists they believed in the Eternity of the world so it didn't have a creator they rejected the afterlife in any meaningful way and they rejected special provenance and short they could really be described as rational in something of the the Greek almost the pre-socratic model but in 1277 there was a condemnation of their ideas by the Bishop of Paris at the University of Paris and that condemnation was really I think riven by the requirement that natural philosophy in the Middle Ages actually were supposed to have the same aim the same purpose that it done in the ancient world because as far as the Bishop of Paris and most Christians were concerned what natural philosophy had to do was provide a model of the universe in which Christianity and Christian ethics in particular made sense and unfortunately the average model simply didn't make sense if it was to provide a world in which Christians could be moral actors so although for Christian natural philosophers the world is created by God it does have its own integrity and John Gurdon who was rector at the University of Paris in the first half of the 14th century emphasizes this in this quotation here where he's explaining how it is that a natural philosopher can understand that God despite having the ability always to intervene in a form of miracle if he wishes to will be usually content to allow nature to run its ordinary course and that is the business of the natural philosopher now again I'd want to emphasize that it's very important when we look at what I consider to be the important parts of medieval science which led us to modern science that we should not be akron istic we shouldn't be patting them on the back for having some ideas but they had absolutely no idea what they were going to lead to I have admittedly said that Greek science was an object of failure in the sense that it didn't describe the way that the world works in that cruet way but it was fair about it medieval science didn't really do that either a medieval science as I said had exactly the same aims as your typical Greek philosophy for Christians the earth sets the stage for moral actors and so there's a requirement that it's bound by real cause-and-effect and moral actors have to be able to act responsibly and that means that determinism has got to be rejected that's one of the central things that the 1277 condemnations were about and actions have to have real consequences and that means that the world requires integrity it's not God who is doing everything we do things ourselves when we act in this world so Christian our Estonians also I think built their natural philosophy as a way of supporting and defending their ideas about ethics religion the meaning of life they really weren't any different from the Greeks in that respect but I think unlike the Greeks eventually medieval natural philosophy did give rise to modern science science in a way that we understand that science which actually explains the world in a reasonably accurate way and so I'd like to just finish off by looking at what I think are three of the most important achievements of medieval science achievements which led directly to the advances made during a period of the 16th 17th century usually called the Scientific Revolution now it's always very easy to talk in generalizations about what kind of metaphysical background was influencing medieval natural philosophers I'm going to do something that perhaps is a little bit more dangerous now and try and homed in on exactly what it was that allowed medieval natural philosophers taking their assumptions to make the advances that they did but I think at the end of the day we probably have to admit that the fact that medievals did make these important advances and it does involve a little bit of cherry picking on my part really in the grand scheme of things is for them or for us just luck they weren't trying to produce the science that we enjoy today one of the things that happened in the Middle Ages is that the barrier between mathematics and physics was broken down Aristotle is very suspicious about the idea of using mathematics to prove a physical theory at times it sounds like he forbids it altogether but an archbishop of canterbury thomas bradwood i explained as far as he was concerned mathematics was the key that unlocked knowledge of physics and what he tried to do was to develop a mathematical formula which described Aristotle's theory of motion now Brad would Ryan succeeded in coming up with a mathematical formula that did that it didn't describe how anything moved but that wasn't really his fault that was because our Stoffels theory was wrong but at around about the same time William of Hattiesburg working not far from here at Merton College developed what came to be called the mean speed theorem and this is a theory which describes the motion of a uniformly accelerating object and this theorem was then proved geometrically during the second half of the 14th century by the French Bishop Nicole RN probably while he was still working at the University of Paris and the diagram on the left-hand side is from a manuscript which dates quite closely to our ends life which shows his graphical proof of the means B theory for uniform acceleration and in the next picture this is a small segment of a late 15th century printed copy of William of haterz breeze original book which set forth the theory and rather helpfully as you can see the printer has included the geometrical proof now one of the people who read this to have to omit rather forbidding book having had a look at look at it myself was a young man studying in Pisa called Galileo and this is on the far left-hand side a diagram from Galileo's most important scientific book the two new Sciences published in 1638 and he uses exactly the same proof rather more boxes this time to demonstrate the way that a uniformly accelerating object will move now what I think is this shows us is that the medieval mind was quite able to combine mathematical and physical ideas the idea that we also find in some medieval sources that mathematics was a perfect a perfect system than thus reflected the mind of God of doing mass trained people to actually lift their heads lift their minds to the divine meant that they were really quite comfortable using mathematics in order to try and understand God's creation and this as I say is something which we really don't find in Greek natural philosophy which always tends to be really a hundred percent qualitative rather than quantative one of the 1277 condemnations won many of them were aimed at the idea that God could be limited and in fact of course as far as the Bishop of Paris is concerned God could create any kind of university liked not just the one that we happen to be in so although everybody believes for instance that the earth was stationary in the middle of the universe it made sense for people to start asking why they've got a created a universe which didn't have a stationary earth it had a rotating one what would that be like and John Bureau Dan again he realized I think a really rather one of piece of intuition that it's not possible to tell if you're simply looking up at the sky whether it's you or the sky move me now this is an idea which the ancient Greeks do mention it's it's mentioned by Ptolemy in his am aghast simply to dismiss it but what buritan does he adds the idea of relative motion and he uses this illustration of when you are on a ship on a strike we'll see you can't tell whether it is you moving or the shore or another ship now we can probably assume that nicholas copernicus didn't read john bureau daily we probably can assume he did read Nicholls kisses on learning ignorance this was a medieval bestseller in the mid 15th century and although this isn't primarily a work of natural philosophy I think it's probably the closest you're going to get to a piece of avant-garde medieval theology it does contain a lot of quite interesting ideas and in particular he uses the ship argument to show that we cannot be certain that the earth is stationary and exactly the same argument the jews by nicholas copernicus in his revolutions in 1543 but what's absolutely bizarre is he claims have got the idea from virgil goode humanist he can't bear to give the medieval scholars any kind of credit at all and finally impetus i mentioned in but as much right at the beginning it was something which probably begins with Aristotle's follower Hipparchus picked up by john philoponus and finally reaches the stage that it's best known to by historians of science with john bureau time and bunin does something very very interesting without their impetus incidentally is just the idea that if you throw something it has some kind of internal force which will keep it moving it was an attempt to keep with our startles idea that a moving object had to have something moving it whereas it's very obvious that if you throw something once it's left your hand nothing is moving it impetus was that something but john muir down realized that he could take that theory a lot further and especially when he asked himself what was causing the planets to move because once you've started something moving something else has to stop it and this is the law of inertia Newton's first law usually its discovery is credited to Galileo as well but I think Bureau Dan gets very very close here he realizes that the planets up in heavens where there's no resistance can be started moving by God at the beginning of the world and after that they will just keep going because there is nothing to stop them and that is a complete opposite of Aristotle's fundamental theory about motion now I think this idea of Bureau dance requires him to believe that there is a God creating the world that sets it going but it also requires him to believe that that God is going to allow the universe to run itself rather than him continuing to have to move every single atom to keep it going so I think Bureau Dan's insight here really is a good example of the sort of idea that Christian natural philosophers of the Middle Ages were having because of the way that they developed the science specifically to support their Christian faith oh it's gone thank you we have a bit of time now for questions but I just like to begin by asking a question on my own because you mention at the beginning of the talk about the failure to develop experimental method among the ancient Greeks we'd like to say something that Roger Bacon's work because having read just recently some of his work on experimental methods I think that's a very very significant was it significant what it was it idea sink rat ik or does it mark a revolution not just by these individual thinkers but the whole way we approach the study of the natural world I have to say not in fact having studied water bacon in depth that his influence was extremely confused if you like his works were I don't think ever quite as popular as the main mainstream scholastic philosophers and by the time you get to the sort of fifteen thirty sixteenth century he's really been transformed into something of a wizard and that did not his his reputation as a scientific thinker no good at all but I think it probably is the case that although he says a great deal about observation he does say things about method I'm not convinced that he does develop what we would consider to be the scientific sort of method of experimentation disproving proving theories really disproving theories and certainly you don't see that developing really at all during the Middle Ages it doesn't appear to arrive really until the 17th century a little bit with Galileo or his methodology is is is not really sort of the classical experiment mental methodology that he's often credited with you maybe you even would say you have to wait until the work by the ignorant Roth society here in here in Oxford and the French equivalents Pascal and alike in the 17th century thank you very much so I think like my colleague dr. Silva will just bring bring the microphone round and I ask you if you have a question just to wait interview you've received the microphone and so your question can be recorded thank you thank you very much you need about the superb book shot some ideas of my own experimentation yes immense intellectual richness in the Middle Ages and the need to completely challenge the nonsense that we have about medieval and things like that but two things strike me first of all experimentation required quantification in a clear sense of nature in measurable units that first yes you had the 360° scale that was inherited from the Greeks from Babylonia and some but unless you have that says something like the telescopic sight in the 17th century you could see nothing smaller than one minute and the measuring rod arcminutes in today's of Hippocrates since it does of Hipparchus so you needed the new data yet of course that say in chemistry or the experimentation that you get to the ARS Magna Baker and some unless you have a concept of a pure substance then you have nothing to measure you know you are dealing with a German earth or a Welsh earth and you heat it and you get this out of it next time you try the experiment you get something different because you don't realize it was a natural product it's a very very complex compound with all sorts of stray bits built in I think one central thing to that idea is what happens after certain 1470 when the voyages of discovery bring a torrent of new information into into the West and these apply to all kinds of things animals astronomical observations what you can see in America you can't see any Engler and things of that kind and the realization that the Greeks are certainly Greek geometry and Ptolemy had been limited in the father they knew nothing of success of America or the Atlantic or the other Pacific they have no idea that for instance that Africa was not joined to the South Pole as a Christian Ptolemy and the sheer flood tide of new data that I think is very very important plus the beginning of new researches into which was beginning the Middle Ages geomagnetism if Peter Peregrine Lestat the 13th century people I think about the first experimentalist it's whether he does work on the nature of how magnets behave but it's his flood-tide of material in geography astronomy optics geomagnetism and so on which present challenges which the the new instrumentation of the telescope the microscope the air pump really then give something that can be measured and tried so I suggest these as ways why in spite of the immense whom richness of the medieval tradition they still in many ways remain deeply philosophical because they needed a new raw data to work on and be better techniques of analysis they were available by the ancestral fingers and Aries well I think it's um one of the most interesting medieval books another one written by Nicholas of kuso's it's a short pamphlet that is urging his readers to measure things away things extremely carefully and that was quite an interesting insight just on on the on the basis that you say I think but I think that one of the interesting things about the first half of what we usually tend to call the Scientific Revolution is that that didn't really represent the creation of new subjects it represented the the final perfection of problems which had been in existence for you know 2,000 years or so and it was only really once those problems have been cracked that science and moves on to conquer new spaces so certainly took a long time to assimilate all that all that all that extra knowledge not significantly important enough that evilly or otherwise thank you I remember learning that one of the medieval explanations of the problem of the the Aristotelian problem of why an arrow continues to fly when not being pushed is that it's compressing the air in the front and creating a vacuum behind which nature abhors so the air rushes round and then proceeds to push the arrow it is that a very what was that a valid explanation which was in the circuit and was accepted do you know I think that explanation appears in not in our shuttle himself you know but quite says that but it does appear I think in some later Greek the sons made two commentaries and it certainly repeated and discussed and quite often rejected by medieval natural philosophers it was it got a name it convenes with P and I can't ever remember how to pronounce it but and I think you also find it in quite a lot of the Arab commentaries on on our Stata lot a state lien I don't think it was ever the orthodoxy but it was certainly something which was discussed played around with and it's one of the things that Bureau Dan uses as a reason for preferring his impetus theory over the our state lien tradition do you have any thoughts about the complementary problem of why why in the Middle Ages there are no new great mathematical ideas compared to great new mathematical ideas of ancient ages great so mathematical ideas yes well I think um I'm not a great expert on the history of math mathematics and I was roundly criticized by one reviewer for not having enough mathematics in my book but I think certainly Nicola REM was quite celebrated and is now quite celebrated as a as a mathematician but a lot of the trouble that people in the Middle Ages had with mathematics was that they had nothing like the kind of notation shorthands that we have today in which were were developed in the arab world and then and perfected in the west things like just as simple as in equal signs and pluses and minuses if you read a piece of medieval mathematics it's all in words and it is extraordinarily difficult to follow for instance you can the the mean speed theory you can write in about four symbols using modern mathematics notation it takes about three lines of quite crap latin for william of haters blue to express the same mathematical relationship using the equipment that he's got so I think it was a huge disadvantage and the development of modern mathematical notation was one of the essential steps that enabled mathematicians to start working I mean it was the tools that they that they needed to start to start developing and we do as you say see quite rapid progress from my round about 1600 and not a huge amount before that could you say something more I'm Helena Cruz could you say something more about the development of the distinction between primary and secondary causes and as far as I know in in Islamic natural philosophy that never happened right so why didn't it or did it but if it didn't why didn't it sir well the the idea is is most commonly associated with her with the 12th century philosopher William of course and it he basically says that he's not going to take anything away from God God is responsible for everything that happens in the world and God is the cause but he is despite being the primary cause he he delegates some causes further down the chain and those are the secondary causes which nowadays we were dim to think of as being the laws of nature and this is expressed if I can just turn to something which I didn't read out by one of one of Williams contemporaries and Gilbert della paura who says all things have been made by God as their author and certain things are called God's work just as they are mainly the things that he makes by himself other things are called works of nature subject the secondary causes and they are created by God but they're created after some natural semblance as a seed is from other seeds and horses are made from horses and similar things come from similar things so the secondary cause is they do give I think we're like two pizzas they give nature and integrity I wouldn't necessarily say that that idea isn't found in Islamic philosophy because the one thing that I have learnt about Islamic philosophy certainly in the Golden Age is just how little agreement there is between early Muslim scholars the variety of Islamic theology is absolutely incredible which goes from the ultra rationalistic to the ultra mystical and absolutely everything in between so you can't really I think generalize about Islamic philosophy and I know that dude does tend to be this this feeling that they were used a philosophy I think of something called occasional ism the idea that God recreates every single moment the entire world so every single second is is God's creation but I mean that is an idea you find in Islamic philosophy but you find a whole lot more as well and I'm simply not anything like well-read enough to sort of give any kind of indication of what was the the dominant idea of doing during any particular period I'm afraid yes very stimulating and take me quite some time too there was a there was a sort of and there was those fragments of history in my education very important people in 17 world people get get parenting us and seventeenth-century and Newton of course and then I think there was some respect for Euclid and perhaps if they're very sophisticated Polonius and but in between there was nothing and I mean why is that you see that the Middle Ages contributed significantly to science in the 17th century and I think it did but it's very hard to pin it down of course you've given the means but I wonder if the the developments were were so deep conceptually so deep that there is very very difficult to articulate because you didn't actually make a case that modern signs gave rise that the medieval science had gave rise to modern science I felt you didn't make that case or did you I probably didn't this evening but that's why I'm concerned modern science means something that started in the 19th century rather than the 17th century I don't think that science as we understand it existed really before the early 19th century so the story between medieval natural philosophy and what I regard as modern science is a long one and it's it's longer than the story is for people who think that science had had a heerd by say the late 17th century I think however that the metaphysical foundation rich medieval Christians laid down for the study of nature and which they did in order to ensure that nature was a suitable foundation in itself for their ethical and religious ideas became totally taken for granted by pretty much everybody in Western Europe until the 18th century and really most people until well into the 19th century the idea is that God created the world but that the world has its own natural laws the idea that the world is not a homogeneous whole that it is it is a creation rather than a thing in itself the underlying assumptions which mean that science makes sense as something to do I think are developed during the Middle Ages and they are essentially continue to believed until science itself becomes so successful that it no longer needs them it doesn't need its own foundations anymore science today doesn't really have in my view very much of an intellectual and philosophical foundation it simply is its own justification its success is its own justification which is why you will find I I find that an awful lot of scientists are what what philosophers call naive positivists in the way in the thing they look at the world but this the case for Christian philosophy the Middle Ages being one of the foundation for science I think is it's not one we can make it a talking about put it that way yes but but I do think it needs to be articulated more clearly and more convincing because yes lots of people say that but it hasn't gone into the mindset of same physics so it's it's almost it's it's true because again I don't think the case has been made strongly I think the case that Galileo's key idea to develop in the 14th century is pretty watertight oh yes oh yes of course and the case that Copernicus had arguments were also developed in 14th centuries it's pretty watertight and that you don't have there's no bright line between the Renaissance and Middle Ages and that medieval science is a it's a continuity which continues to run into the 16th and 17th centuries I think that case is pretty well made by something I mean not by me but by by by historians of science and pretty convincingly made by them thank you very much as I really very clear in fascinating talk and you focus mostly on the understanding of order in the cosmos and in both Greek and medieval philosophy I wonder if you could say a little bit about the place of disorder and and I'm not sure I knew if I much survived it but I think it's true that some of the early Greek philosophers accepted the ideas of randomness as being responsible for the evolution of strange animals that were half man half horse or a dog with wings and stuff like that that could just spontaneously arise by mixing things up randomly and I wonder if the medieval philosophers gave this idea any thought at all or was there any consideration of chance processes in nature of a randomness or a chance in nature I think the idea that something was happening for no reason would have been fairly alien to our Christian philosopher of really for two reasons firstly because you do have the idea of God being here watching courts of everything but also there are estate lien inheritance which did emphasize that when you looked at nature if you look at animals all animals have a reason a purpose his natural history is is highly teleological so I think that although you have a lot of you have popular literature which talks about monsters and that sort of thing and you have actually quite learned disquisitions on questions like whether the dog headed men really exist and what they might be like and whether or not they can be converted to Christianity and all that sort of thing but what might perhaps have originally started off being some kind of marvelous monster by the time it gets to the Middle Ages by the time it has been sanctified by sort of 2,000 years of history it ceases to be something monstrous it become part of nature and something that they want to talk about is the same kind of way that they would talk about ordinary animals and plants and people that we we wouldn't consider to be monstrous at all so could you expand a bit apart on the theme of the of nature being alive its freedom to operate under secondary causes as a way of as it we're preventing determinism from controlling every aspect of life but was it to simply allowed freedom as long as it stayed within the rules the laws of nature um what determinism the kind of determinism which was being attacked in the 1277 condom Nations was the determinism that human beings essentially weren't responsible for their own actions the kind of extreme astrology that said that you know everything is determined by our stars where we're born whether we're good or bad is not up to us so the kind of determinist and it really makes a Christian morality philosophically impossible but I think that Christian scholars were concerned to ensure that when people did things they had real consequences and the doctrine of second two causes of the integrity of the universe allowed them to say that so that you know you you can't if I do a deed and I've done it's not something which either has been determined by my stars or to the fact that Automation or by thought and I think also you know in in in in in popular Muslim thought and indeed in some popular Christian thinking you you do have the tradition of people even blaming you know misdeeds and on that sort of thing on on on God and he's fine not in Christianity as well on uh on a large scale like you know the Turkish invasion of by that by the Turks was was the scourge of God but on an individual basis I don't think you see that so much just on the you mentioned that sort of Plato when he saw something that didn't quite fit with his sort of worldview or his cosmology he saw the wandering planets he said sort of just ignore them because it basically the that was sort of subservient to his ethics and and that's what was sort of most important so when we make new discoveries they might have some effect on our ethics and there might be and there has been resistance to that so also in the in the in the medieval ages you've got wonderful things like architecture amazing cathedrals are being built and which perhaps as a technology which we've lost so that there had understandings about things that's that's we don't know how we've got we're sort of lost there so right now how can I fix and sort of science and how can they sort of is there a method that they can follow to be more articulate so I'm not very articulate well I think I think I think that the interaction between ethics and modern science is an absolutely key problem for the modern world because science doesn't give us a grounding in ethics anymore we have unlike in the Greek and medieval worlds we have an almost complete divorce of science from dicks and scientists quite like it that way the spot was I can tell in general so how you you inject some kind of ethical meaning into science so that science is not treated as just having some kind of a moral right to investigate anything it likes and to have with the consequences I think it's terribly important but but anyone as far as I can tell her who suggests that science should exercise some kind of self-restraint is I'm promptly accused of being well medieval want a better word okay thank you actually it was I was asking actually it's ethical question about the contribution of Christian thought in the middle medieval philosophy and the fact that also you say that science philosophy as the question what I am for and I was I was the question my question is whether or not science now in our 21st century is losing his wings by not asking this question actually by not asking this question what I am for and also the fact that paradoxically philosophy have a huge contribution on Christian thought like Aristotle in the emergence of people thinking more and better about doctrinal theology at the same time we have the lost of Christian thought in science how could you spend that now thank you the sizes and shoe size may be asking what with yes I mean yes whether or not sounds way better if he actually did what the middle-aged people were doing by actually having kind of Christian foundation like decart for instance you have a kind of Christian God in his mathematic philosophy today could we learn something from the Middle Ages well I certainly think we can learn something from the way that the Middle Ages was able to combine patterns of thought which for us are are separated and ethics and science were really the whole whole idea of the world as being a big homogeneous whole although Han I'm not a romantic for the Middle Ages I have to admit I'm very pleased I don't have to live in the Middle Ages and I think we need to be quite careful as even as we try and give the Middle Ages a fair crack at the width as historians and not privileged other areas of history which might initially appear to be more appealing I think we also need to be careful not to fall into the trap of romanticizing it and imagining actually we haven't made really quite substantial progress in in all sorts of areas not just in science but in political Liberty personal liberty I don't think we would want to go back to living in the kind of world of the Middle Ages were really the amount of intellectual space that most people were able to move in was was I think quite limited thank you that was very assessment I actually wonder what final comment because I was at a meeting with some very senior physicists earlier this week and what was interesting was the contrast between the extreme sophistication of the science and the simplicity of the philosophical questions such as what is truth what is knowledge these questions kept coming up so I think the basic conclusion is that physicists today probably could do just studying a little bit of the humanities as well maybe the hyper specialization is is inhibiting us in certain ways but I have a final quick question for you James now as you were talking I was thinking of other things as other connections you might try to make like the contribution of the measurement of time how that affected science or perhaps the growth of the body of other body of law and how a notion of jurisprudence how that affected science if you had more time what other topics would you choose to talk about I think one thing which I do consider to be terribly more much I didn't really touch on at all is that the intellectual world of the Middle Ages was was united and you have this this wonderful combination of a shared intellectual culture inside a fragmented political unit and that meant that I think there was lots and lots of potential for cross pollenization it was almost impossible to completely stifle any particular ideas people were always able to move if they found a particular home to being conducive and that I think is an advantage which Europe has has had ever since then and have to has to this day that there is the sense that European culture is is one but it's also many and I think that that has been enormous benefit to the development of science and a great deal else well thank you very much indeed just before I conclude and a thank you to thank let's bake a brief over spent for our next Ian Ramsey Center seminar and I will be talking on the ambiguity of cosmic purpose and the challenge of wisdoms parable the parable in question being written a famous account by a philosopher John wisdom also used by Antony flew does the universe show signs of purpose or not and the ambiguity of it so that'll be in two weeks time two weeks time at the same time here at Trinity College so the include would you join me now in thanking dr. Jane's hanim

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Published: Sat Oct 20 2012