In Our Time: P v NP

P v. NP is one of the unsolved problems in computer science, essentially the question is: can all problems whose answer can be quickly checked for correctness by a computer also be quickly solved by a computer? At the moment the consensus is “no” but there is a $1million reward for anyone who finds an algorithm that works, and if someone does then current computer security measures are all compromised because encrypted passwords will become trivially crackable. The experts discussing it on In Our Time were Colva Roney-Dougal (University of St Andrews), Timothy Gowers (University of Cambridge) and Leslie Ann Goldberg (University of Oxford).

This was a bit of an odd episode of In Our Time, as it felt like Melvyn Bragg was significantly more out of his depth than usual. Whilst his role is to ask the Everyman type questions, in this one he seemed to be asking for clarification on the wrong things – like wanting to know why algorithms are so-called rather than accepting it as technical jargon. Or repeatedly wanting clarification on why NP problems are hard because he clearly hadn’t grasped the issue – although the experts are partly to blame here because I think they didn’t put enough emphasis on wanting the optimal solution to their example problems rather than the sort of “good enough” answer that we actually use in everyday life. Because of this I didn’t really feel like I learnt anything much from the programme & I don’t consider myself particularly well educated on the subject (just see my clumsy summary at the beginning of this post for evidence of that!).

The programme started with a couple of bits of background information – first the invention of computers (as a theoretical idea) by Alan Turing. He imagined a machine that accepted inputs, generated outputs and at any given point would know what to do based solely on its current state and the symbol it was currently looking at. This is the theoretical underpinning for how all computers work. This segment felt a little detached from the later discussion, but I think the linking idea was that Turing also realised that even with this sort of computing machine (which would do calculations much more rapidly than a person could) there would still be algorithms that would fail to finish in a sensible time (like before the end of the universe).

The other piece of background information was a brief discussion of what algorithms are. In essence an algorithm is a series of instructions, Roney-Dougal used the example of a cooking recipe as an algorithm for making some specific food. It was stressed that algorithms generally aren’t entirely linear – they’ll loop back on themselves to run through several steps multiple times.

The difference between P and NP problems boils down to how the time taken to solve the problem scales when you increase the number of items in the problem (n). As I said above, what wasn’t stressed on the programme was that by “solved” they meant “found the best possible answer”. P problems scale in a polynomial fashion – hence the P nomenclature, although Gowers said you could also think of them as Practical. As n increases the time taken increases by some polynomial amount, for instance n2: i.e. if there’s one item then the algorithm takes 1 unit of time (whatever that might be); if there are 2 items, then it takes 4 units; 3 items = 9 units and so on. So the amount of time taken increases faster than the number of items does, but relatively slowly and given sufficient computing power the algorithm will finish running in a useful timescale for practical applications. Goldberg gave an example of this sort of problem: say you have a group of people and you want them to work together in pairs, but not everyone likes everyone else. As the number of people in the group increases then the number of combinations you have to look through to check whether it’s the optimal solution or not goes up. But it goes up in a polynomial fashion so an algorithm that does that checking of possible combinations will finish in a sensible time.

NP problems are those that are not P. The number of possible solutions increases exponentially rather than polynomially, and as n increases a “dumb” algorithm that just checks every one in turn will very quickly get to the point where it will take billions of years to complete. (And if computing power increases then all you do is push that point just a little further out, but not far enough to make a practical difference.) The P v NP question is concerned with a sub-group of the NP problems that are called “NP complete” – these are the ones where a potential answer can be easily checked for correctness by a computer, but the answer cannot be trivially found. And the question is: can we figure out a clever algorithmic “trick” to turn an NP complete problem into a P problem, hence making it solvable.

They discussed a few examples of NP complete problems – one of the better known variants is the Travelling Salesman problem. In this you have a number of cities (n) linked by roads, and the salesman wants to travel to each one once and only once, and use the shortest possible route to do so. With small n you can figure out the answer by inspecting all the possible solutions and discovering which one’s best. But as n increases the number of routes goes up exponentially and this becomes a non-viable way of attacking the problem. Obviously for this specific scenario we find “good enough” answers for real world purposes (deliveries from central warehouses to local retail outlets, for instance). But if any of those answers is the optimal solution then that’s by chance rather than because the distributor figured it out.

To give another example, Goldberg returned to her example of a P problem – dividing up a large group into pairs of people working together optimising it for most people ending up working with the best possible partner. When it’s pairs, it’s a P problem … but if you’re looking to divide them into groups of three then it’s an NP problem. Another example is seating wedding guests when many of them hate many of the others, and optimising for fewest arguments. And all modern cryptography is based on an NP complete problem – passwords & so on are encrypted using a method involving multiplying together two very large prime numbers. To reverse engineer that (i.e. crack the encryption) you have to find the prime factors of a very very large number, which is an NP complete problem, so a brute force approach won’t complete until long after the lifetime of the person who might find it useful. (Decoding it by the intended recipient is a case of checking an answer you’ve been provided, which is easily done for NP complete problems.)

Although these examples of NP complete problems all sound quite different mathematically speaking they collapse to the same underlying problem. You have a collection of nodes (cities, guests, whatever) which are joined by links of varying lengths (roads, levels of hatred, etc) and you’re looking for the shortest route between them. So if someone figures out an algorithm that turns one NP complete problem into a P problem (i.e. finds that P = NP) then all NP complete problems are solved. Which has both good and bad implications for how our modern world works. On the bad side, all our encryption is broken so no more secure payment sites, no secure online banking (amongst many other effects). But on the other side many products may become cheaper – it’s pretty likely that our “good enough” answers to the Travelling Salesman problem aren’t the optimal one, and once you can move things around optimally then logistics gets a lot more efficient. Circuit design also gets a lot more efficient.

However, most mathematicians think that we won’t find a solution to NP complete problems (i.e. that P != NP). As yet no clever ideas have played out, but there is that $1million reward if someone does find a solution. The experts briefly mentioned that quantum computing had once seemed a promising lead – using quantum entanglement to make the right answer somehow pop out without needing the time to do the calculations. But this was another lead that didn’t go anywhere. (Although cynical me did think that if it had been made to work by some government agency or another, then we’d not know it had …)

In Our Time: The Empire of Mali

The Empire of Mali flourished between 1200 & 1600 CE, in sub-Saharan West Africa. At one point the Empire was so wealthy that when its ruler, Mansa Musa, travelled through Egypt on his Hajj he reduced the value of gold in Egypt with the amount he gave away. Discussing the empire on In Our Time were Amira Bennison (University of Cambridge), Marie Rodet (SOAS) and Kevin MacDonald (University College, London).

The beginnings of the Empire of Mali (c.1200 CE) are only known from an epic which survives in the oral tradition of the region. There was a prophecy that Sundiata Keita’s mother would bear a son who would become a powerful king, and so the ruling king married her (I think despite her ugliness in some versions). Sundiata was crippled at birth, which cast the prophecy into doubt, but he later was miraculously cured. When his father died, his older half-brother took the throne and sent Sundiata and his mother into exile. Sundiata grew up in a neighbouring kingdom and became a renowned warrior. He eventually returned to Mali to liberate the people and take his rightful place as king – founding the empire that would last the next 400 or so years.

The experts discussed how this is more an origin myth than factual. It’s part of the oral tradition, and is intended for performance and each performance is tailored to a greater or lesser extent to it’s audience. For instance places that are referenced tend to be locally relevant. And there are things that can be picked out as definitely having changed since the original composition. In many versions Sundiata is Muslim, but we know that Islam didn’t make significant inroads into Mali culture until later in its history. In some versions he’s even supposed to be descended from a companion of the Prophet Mohammed’s who was a freed black slave, and other versions don’t give him that sort of genealogy at all.

Another part of the oral tradition surrounding the foundation of the Empire is that Sundiata Keita laid out a constitution for how the Empire should be run. Amongst other things it set down how the justice system should work, and the details of the caste system. In the late 20th Century CE this was written down, it is now categorised as a piece of World Heritage and sometimes referred to as Mali’s Magna Carta. The experts were keen to point out that because it’s an oral tradition you have to exercise care in how you interpret it. As an analogy (which I don’t think they used on the programme) the English Magna Carta survives in a couple of original written documents, and when you compare that to what it’s become in our national mythology you can see that the latter is based on the former but they are definitely not identical.

The Mali Empire covered a large east-west expanse of West Africa, running from the Atlantic coast to Gao. Like most empires it consisted of a core territory that was ruled directly by the Emperor and this was surrounded by client states ruled by client kings. The primary source of Mali’s wealth was gold – they had the largest gold mines in the world at this time. They also traded with the Islamic world across the Sahara Desert – the nomadic Berbers of North Africa traded with Mali for both gold and grain.

Over time the Mali Empire gradually became Islamic. This doesn’t seem to’ve happened as the result of direct efforts to convert them, instead the religion arrived with Berber traders some of whom settled in Mali and practised their religion. Once the emperors became Muslim it spread more quickly through the Empire, mixing as it went with their traditional animist beliefs. As I said in the introduction to this post one of those Emperors, Mansa Musa, went on Hajj. He travelled in state over land via Egypt accompanied by a large number of his court, and took with him plenty of gold for gifts to the places he passed through. He wasn’t just fulfilling his religious obligations, he was also searching for Muslim scholars who would be willing to take employment in his court and travel back to Mali with him. One of these scholars who came back is credited with having founded hundreds of mosques all across Mali – which seems unlikely to’ve actually happened. Some perhaps were state foundations, although they are still unlikely to’ve been founded by this one outsider. And they generally have local architectural styles, rather than Arabic or Spanish designs. It seems much more likely that these are instances of towns trying to gain prestige by claiming a famous origin story for their mosque.

The majority of evidence for the Mali Empire, and its inner workings, is second hand. Much of the written evidence for the empire comes from these Muslim scholars discussed above and others who travelled to Mali. Other evidence comes from the Songhai Empire which replaced the Mali. The Muslim scholars seemed to’ve regarded Mali as somewhere different, but nonetheless civilised. For instance when writing about their justice system it is described as effective, even if it wasn’t what the observer was expecting.

The Mali Empire began to disintegrate in the 17th Century CE. The experts said that this was down to it becoming overstretched “like all empires”. Control of the periphery began to decline, and territories started to break off and become independent. One of these was Songhai, and this ex-vassal would go on to conquer the territory of the Mali piece by piece from the West. Another factor in the decline of the Mali Empire were the destabilising interactions with Europeans on the Atlantic coast of the empire. They noted on the programme that one of the commodities that the Mali traded in was slaves, and the selling of slaves to Europeans began the transatlantic slave trade.

Until relatively recently historians were dismissive of the Mali Empire – for instance it was assumed it was ruled by Muslim Berbers, rather than the people who actually lived in the country. This unthinking rejection of sub-Saharan African civilisation was bolstered by a lack of archaeological evidence to contradict it. However more recently there has been a resurgence of interest in African history in general and the Mali Empire has become something worth researching. This has lead to new information, including archaeological discoveries, particularly in the region where the capital city of the Empire was.

In Our Time: Holbein at the Tudor Court

Hans Holbein the Younger was one of the foremost portrait painters to work in England during the Tudor period (and perhaps ever), and it’s his paintings that shape how we see the court of Henry VIII. Discussing his time at the Tudor court on In Our Time were Susan Foister (the National Gallery), John Guy (Clare College, University of Cambridge) and Maria Hayward (University of Southampton).

They started the programme by setting the scene for the Tudor court of 1526, when Holbein first arrives. At this point Henry VIII has been on the throne for 17 years. Cardinal Wolsey is still his right hand man, and Anne Boleyn has just arrived on the scene. In terms of international politics there has just been a bit of a shake up. Previously Henry VIII was allied with the Spanish against the French – there had been a plan that the two countries would co-ordinate an attack on France, and once successful Henry VIII would get to keep northern France (and be crowned King of France) and the Spanish would claim southern France. However the Spanish had won a victory over the French, but then not divided the spoils with England as Henry VIII thought they’d agreed. So the alliance had broken down, and now Henry VIII was allied with France. Which is another factor in the waning influence of Henry’s Spanish wife, Katharine of Aragon, and in the rising influence of the French educated Anne Boleyn. I don’t think I’d heard anyone explicitly point out this political connection before, the narrative generally focuses on the need for an heir and “true love”.

Hans Holbein’s father was also called Hans Holbein and was also an artist, so generally “the Younger” and “the Elder” are appended to their names to disambiguate them. I don’t think they said on the programme where Hans Holbein the Younger was born, but it was in continental Europe (Germany, if I remember correctly). He was probably educated alongside his brother, by their father, in a wide variety of artistic techniques and media. This included goldsmith designs and techniques, frescos and other sorts of painting, and producing illustrations for printed books. This last was particularly emphasised by the experts on the programme as a new and lucrative market for an artist at the time. In early adulthood Holbein and his brother move to Basel (Switzerland) where they make a living mostly from illustrations and engravings, but also from religious paintings.

Holbein was looking for an opportunity to become a court painter (as it was a lucrative and prestigiuos position to hold). I think they said he had tried to get employment at the French court, but not had much success. In 1526 he moved to London, with a letter of introduction from Erasmus to Thomas More. He had probably sent ahead his portrait of Erasmus as a showcase for what his skills were. Thomas More was apparently not very optimistic about Holbein’s chances of employment in London. He wrote that England was “not fertile ground” – tapestries and theatrical sets where the dominant arts in the country at the time, not portraiture. But the experts suggest that with the benefit of hindsight this may have been because there wasn’t an accomplished portrait artist available until Holbein arrived.

During this first stay in London there doesn’t seem to’ve been much work – he started by being employed to paint theatrical sets, and he also undertook some commissions from Thomas More and from some other members of the elite (although not necessarily the court). Holbein returned to Basel – they weren’t clear on the programme why, nor if he originally intended to stay there. I’m not sure if that’s coz it isn’t known, or if it’s just that the programme was concentrating on his time in Tudor England so they were skipping lightly over the other information.

In 1532 Holbein returned to London. This is just as Anne Boleyn and Henry VIII finally get married, and there is some evidence that Anne Boleyn is a patron of his. There are no records available to say whether or not she actually paid him for anything, but there are several paintings with links to her. Including one painting of her in her nightgown (for which read “dressing gown” not “nightie”) – so he had access to her in informal settings such as her bedchamber which is a distinct mark of her favour. He is also first recorded on Henry VIII’s payroll during this time – so he has achieved his ambition of becoming a court painter. Although apparently he wasn’t paid as well as he might like – the French court painters received more money and more privileges from their king!

Holbein clearly had a knack for politics, or rather for staying out of politics. He remained in the employ of Henry VIII until his death in 1543, through the downfall of Anne Boleyn, and even weathered the storm surrounding Henry’s brief marriage to Anne of Cleves. When Henry was looking for his fourth wife, Holbein was the man sent to the courts of Europe to paint the potential brides. The two best known paintings are that of Anne of Cleves and that of Christina Duchess of Milan (who turned Henry down). It’s known that Holbein didn’t actually get to paint the whole Christina’s portrait from life – he had one 3 hour sitting with her, and quite probably only brought drawings back to London which he subsequently turned into a painting. It’s really quite remarkable that Holbein didn’t fall into disfavour after Henry’s marriage to Anne of Cleves failed almost before it began. Henry’s complaint was that he found Anne too ugly, but there’s no indication that he blamed Holbein for misrepresenting her (he did blame Cromwell, however). And the experts said that Holbein probably didn’t misrepresent Anne – despite Henry’s distaste she seems to’ve been regarded by contemporaries as a handsome woman. Probably the most Holbein did was minimise the German-ness of her clothing and headdress, so she would look more fashionable to English eyes.

As well as this overview of Holbein’s career in England the experts also discussed some of his better known paintings – you’d think that would be quite hard on a radio programme but I recognised all the works they discussed from having seen them previously, so had the right mental images. One of them was one of my favourite things in the Portrait Gallery when I visited it last year: the surviving half of the cartoon for the Whitehall Mural. The finished piece (which doesn’t survive) was a large dynastic portrait of the Tudors so far. On the left were Henry VIII and his father Henry VII, and on the right were their wives – Elizabeth of York for Henry VII and Jane Seymour for Henry VIII. The timing of this portrait is around or just after the birth of Edward VI, Henry VIII & Jane’s son. The cartoon is the same size as the painting was, so we can see that the viewer would’ve been presented with a lifesize image of the King standing directly in front of them – apparently terrifying for those who saw it. Inspection of the cartoon shows that originally the figure wasn’t full frontal, but Henry apparently wanted that changed so it would have the maximum impact.

Another of the paintings they discussed was the girl with a squirrel that we’d seen in the British Museum’s Germany exhibition in 2014. This portrait combines a clever use of symbols with a warm & touching portrait – the squirrel is not just the girl’s pet, it’s also part of her family’s coat of arms. And they also discussed The Ambassadors, which I think of as “the one with the weird skull in front”. This painting is also not just a portrait of the two men – it also showcases Holbein’s skill at painting many different objects. Including the distorted momento mori motif of the skull, which looks just right if viewed from the side of the painting.

Even at the time of Holbein’s death he was regarded as a particularly good portrait painter, and his reputation has only increased since. As I mentioned at the beginning of this post, Holbein’s portraits are how we see Henry VIII’s court. Those paintings are what shape our mental image of “the Tudors” and are what take them from a collection of dates and facts and turn them into people in our collective imagination.

In Our Time: Perpetual Motion

Perpetual motion would be a wonderful thing, if only it were possible – being able to set some machine going and then it would power itself and just carry on & on without end. Free energy from nothing! Which is, of course, why it is impossible – but this wasn’t provable until relatively recently. Discussing the search for, and disproof of, perpetual motion on In Our Time were Ruth Gregory (Durham University), Frank Close (University of Oxford) and Steven Bramwell (University College London).

Before the modern understanding of physics there didn’t seem to be any reason why perpetual motion should necessarily be impossible. In the Aristotelian view of the universe the stars were in perpetual motion in the heavens – so there must surely be some way to replicate this on earth with earthly machinery. This wasn’t (solely) the province of charlatans – people like Leonardo da Vinci, Robert Boyle and Gottfried Leibniz were all involved in attempts to design machines that could power themselves forever. Various approaches were tried – like trying to design a waterwheel that not only ground corn but also pumped the water back uphill so it could flow down again. Or a bottle that siphoned liquid out of itself in order to refill itself. Or some sort of machine that was constantly over-balancing – like an Escher drawing of a waterwheel with buckets labelled 9 travelling down one side, and when they reach the bottom they flip round to now read 6 so they’re lighter. Which works beautifully in the illusory world of Escher’s art but rather less so in our mundane reality. As well as people genuinely trying to investigate the possibility there were also those who claimed to have achieved success – normally with machines that conveniently couldn’t be inspected to expose their charlatanry.

Once physicists started to gain a greater understanding of how the universe worked it became clear that perpetual motion machines were fundamentally impossible. All proposed perpetual motion machines violate either the first or second law of thermodynamics. Before moving on to explain how these laws affect perpetual motion machines they digressed slightly to explain some of the background to the formulation of the laws of thermodynamics. First they gave us the technical meaning of the word “work” in a physics context – important in understanding the rest of the discussion. Work is the energy that is applied to do something. For instance if you want to move something then work = force x distance. Or if you’re heating something up then work refers to the energy you need to cause the temperature change. Experiments by Joule were key to showing a link between heat and energy. Before his work the prevailing theory was that heat was a thing (called calor) that could be transferred between objects – so a fire heated a pot because calor was transferred from flames to pot. But Joule showed that you could generate heat using energy, and later it was realised that heat was a form of energy. Reception of his work at the time (the mid-19th Century) was mixed – the temperature changes he was study were very small and not everyone believed it was possibly to accurately detect them.

The First Law of Thermodynamics is that energy must be conserved in a closed system. I.e. you don’t get something for nothing. When work is done it all turns into motion or heat or some other form of energy. Many perpetual motion machines violate this law, and they are termed “perpetual motion machines of the first kind”. An example of this is a waterwheel that both grinds corn and pumps the water back up to the top to start over again. In order to pump all the water back up you need to use just as much energy as it generated for you on the way down – so there none left over for your corn grinding, even if your machine is perfectly efficient (see below).

The Second Law of Thermodynamics is that entropy always increases or remains the same, it never decreases. Gregory used the example of a room that’s either tidy (a single ordered state) or untidy (many possible disordered states). In order to move from disordered to ordered you need to do work, otherwise over time the random chance will move objects from their positions in the room and it will become more disordered. The Second Law of Thermodynamics is associated with time – it provides directionality to the universe, if things are getting more disordered then they’re moving forwards. Perpetual motion machines which violate this law are categorised as “perpetual motion machines of the second kind”.

Another way that perpetual motion machines can violate the laws of physics is by being too efficient. I touched on that above – in the real world no machine operates without losing some energy (generally in the form of heat due to friction). And so even if you aren’t trying to do anything useful with the energy other than keep the machine moving you’ll still fail to achieve perpetual motion as you won’t have quite enough energy to return to the starting point.

So perpetual motion is impossible, as it would violate the laws of physics. There are some loopholes at the quantum level (aren’t there always?). Implications of the Heisenberg Uncertainty Principle mean that it’s possible to “borrow” energy temporarily from the future, which means the First Law of Thermodynamics doesn’t quite apply. But at the macro level these laws are inviolable and perpetual motion is impossible. They finished by saying that if a way to make a perpetual motion machine work was found then it wouldn’t just be a case of minor tweaks to physics-as-we-understand-it. Instead it would require a re-writing of pretty much all science we’ve ever conceptualised – the laws of thermodynamics are that fundamental to our understanding of the universe.

In Our Time: The Roman Republic

The Roman Republic was the subject of an In Our Time episode all the way back in 2004 – we listened to it last August while there weren’t any new In Our Times airing. It’s a pretty broad subject for a 45 minute programme – 500 years of history plus its rise and fall – so of necessity it was painting with fairly broad brushstrokes and looking at themes and commonalities across the centuries. Tackling it were Greg Woolf (St Andrews University), Catherine Steel (University of Glasgow) and Tom Holland (historian and author). (NB: Institutions presumably out of date, it being 12 years ago.)

They started by talking about the foundational myths of the Republic as the stories they told themselves shaped how the Republic functioned. This isn’t Romulus and Remus – they are a foundational myth for the city – instead the two key stories are the rape of Lucretia and Horatius on the bridge. Lucretia was raped by the son of the King of Rome, and afterwards she committed suicide whilst calling on her kin to avenge her. This sparked an uprising (led by a man called Brutus) which drove out King Tarquin. Following this the Romans declared they would have no more kings. The second legend follows on directly from this one* – Tarquin didn’t take kindly to losing his kingdom like this, and enlisted the support of one of the nearby Etruscan cities. He returned to Rome at the head of an army and it seemed like the Romans were going to be forced to take their king back. However before this could happen Horatius stepped forward to stand on the bridge the army were marching over. He and two companions held off the army for long enough for the bridge to be destroyed behind them, preventing the army from reaching the city. So you have this ideal that the people will rule themselves (with no kings) and when a hero is needed a citizen will step forward to give his own life for his city.

*Well, that’s the way they told the legend on the programme, when looking it up on wikipedia to check spellings of names I saw that there it’s set much later in the Republic’s history – the point remains the same though.

The Roman Republic was the first constitutional democracy meaning that people were voted into positions of responsibility. (Athens was a direct democracy, where everyone voted on what should be done.) The political structure was based on sharing power around in two different ways. Firstly the many powers that a king had once had were distributed between several people. Secondly any given person only held a particular office for a short term (rather than for life). The ephemerality of power and glory were a key concept for the Republic. A consul was consul for a year. A general who’d won a victory was given a triumph and treated like a god for a day. Theatres and celebratory buildings (like triumphal arches) were temporary structures. Even the permanent infrastructure buildings weren’t built of stone but of more ephemeral materials. Which puts the Emperor Augustus “coming to Rome a city of brick and leaving it a city of marble” (as discussed on the In Our Time about the Augustan Age (post)) in a different light: that’s not just an upgrade to the buildings, that’s a change of ethos.

Clearly the Republic wasn’t static over its 500 years of history – in particular the balance of power between the people and the aristocracy was constantly shifting and evolving. But it was at heart a very conservative society which looked back to a prior Golden Age. Much was written in later days in the Republic about how it had been better in the early days (before whatever the most recent crisis had been) – and this genre includes most of the surviving texts written about how the Republic was founded. Changes were often brought in by announcing that they were returns to the ways things were done in the past – whether or not this was actually true. This continues after the Republic as well – they brought up on the programme that Augustus’s propaganda cast the beginning of the Empire as a restoration of the good old days of the Republic.

The end of the Republic can be thought of as it becoming a victim of its own success. Before they went out and conquered such vast lands it was possible for every key political figure to come back every year to Rome and vote for the new Consuls and so on. And when your campaigns only last a year and are nearby then the army can be based on the idea of farmer-soldier citizens. Every able-bodied land-owning male citizen was supposed to enlist – easily done when he comes back in time for harvest, but what do you do about his farm if he’s on campaign for 5 years at a time? And once the land-owning requirement was abolished where do long term soldiers retire to when they’re done in the army? The Senate generally prevaricated over the provision of awards and recompense to these retired soldiers – which left a gap for the generals of the armies to fill. And if your reward would come from the charismatic general you were serving under, then your loyalty would be to him first rather than to Rome or to the Senate.

The Triumvirate of Pompey, Crassus and Caesar (the first stage in the transition from Republic to Empire) can be seen as having grown out of Pompey not liking his downgrade in status when he returned to Rome. Whilst out campaigning in the East he had been treated like a king, back home in Rome he was only one amongst equals. And not a particularly important one at that – having been away he was out of the loop, politically speaking. The experts said that Caesar’s motivation was probably that he saw there as being only so many “slots” for important people in any new regime and he wanted to make sure he occupied one of them.

The defining point for the end of the Republic was the crossing of the Rubicon by Caesar and his army. The Rubicon is a river between Italy and Gaul, and it marked the boundary between the provinces (where a general could be a king in all but name) and the core territories (where the general was no more important than any other aristocrat). The tradition was that you could not bring your army with you into the core – and so Caesar camps on the other side, which makes the Senate nervous. He’s given the choice between dismissing his army and crossing himself, or taking his army and leaving. But Caesar knows that if he does this then he loses all the power he’s worked for – and so he brings his army across the Rubicon.

I said that was the defining point of the end, but as they discussed on the programme that’s only obvious with hindsight. It probably wasn’t clear to the Romans that the Republic was gone forever until one Emperor inherited from another … and perhaps not even until an Emperor was deposed and yet still the Republic was not not restored.

In Our Time: The Estruscan Civilisation

The Etruscans were one of the other cultures to live in Italy in the 1st Millenium BCE. They are often overlooked in favour of the Romans (who conquered them), but they were a power in their day and even ruled over Rome for a while early in its history. They were the subject of an In Our Time episode from 2011 which we listened to recently, and discussing Etruscan history and culture were Phil Perkins (Open University), David Ridgway (University of London) and Corinna Riva (University College London).

The Etruscan culture began around 800 BCE and lasted for the next 800 or so years. They lived north of Rome in an area roughly the same as modern Tuscany – the similarity of the words Etruscan and Tuscany is not a coincidence. Their origins are obscure, Herodotus said they came from Lydia (in modern Turkey) and there is some controversial DNA evidence that suggests a Middle Eastern origin but as described by Perkins* this is unconvincing. The study only looked at Y chromosome sequences from modern inhabitants of Tuscany, and it’s not clear how (or if) they decided who was likely to’ve been descended from the Etruscans. Nor did their results give any indication of when this Middle Eastern origin was so it’s not clear if it has any bearing on distinguishing the Etruscans from other inhabitants of Italy – after all, most of our ancestors in Europe came via the Middle East on the way out of Africa many 10s of millennia ago! The consensus from the experts on the programme was that this was all rather implausible, and it was more likely that their immediately preceding history was as inhabitants of Italy. Interestingly, however, their language is not an Indo-European language and has no modern relatives.

*Perkins didn’t explain it terribly well though – I wasn’t clear if he didn’t understand it very well or if he just wasn’t producing a coherent explanation.

There is not much surviving textual evidence from the Etruscans themselves – most of what is written down is by the Romans. There is no surviving Etruscan literature at all, and only a few inscriptions. These are in both temples and tombs and written in a modified Greek alphabet, but they just tend to name people or gods and give genealogies. Why there is no literature is an interesting question with no clear answer. It seems implausible that they didn’t produce any written literature – given the time and place where they lived, and the level of sophistication, wealth and power shown by the archaeological evidence. This implies that the literature was destroyed – and one persistent theory is that there was a purge during the time of the Roman Empire (after Claudius was Emperor, I think they said) to wipe out the memory of their rival civilisation. Nobody on the programme was willing to say that this was true, but they seemed to agree that it was pretty plausible it’s just there’s no evidence for it one way or the other.

In contrast to the paucity of texts from the Etruscans there is a wealth of archaeological evidence. The way they phrased it on the programme was that in Tuscany it’s not the Roman ruins you go to see, it’s the Etruscan ones. Even by the standards of Italy this is an area rich in ancient sites. Tombs and graveyards are the main sources of information about the Etruscans – these sites include grave goods, wall paintings and some inscriptions. A few temples and city buildings have also been excavated.

Thinking of the Etruscans as a state is anachronistic. Like Greek culture of the time they were a group of independent city states which shared a common language, culture and religion. Their religion is only known from what the Romans wrote about it, but it appears to’ve been different in emphasis to the surrounding cultures. The origin story for their religion is someone (a mythical/mystical figure) teaching them how to interpret the omens. The worshipper doesn’t pray to the gods and ask them for help or favours. Instead one’s religious duty is to interpret the messages the gods are sending via signs & portents – a one way route of communication.

The 6th Century BCE was the heyday of the Etruscan culture. The hills of Tuscany have rich mineral deposits including both tin and copper. Together these metals make bronze – and so were much sought after at the time. The Etruscans could not only outfit their own people with weapons and tools, but also traded extensively around the Mediterranean. They were later called a warlike people, but the consensus on the programme was that there’s no evidence of them being worse than anyone else at the time. This was, after all, a warlike period. Their artistic culture is sometimes dismissed as “copying the Greeks but getting it wrong” but the experts were unanimous in declaring this bobbins (rather more politely tho). The Etruscans had a sophisticated artistic and architectural style, which had clearly been influenced by the Greeks but was also uniquely their own. They did often employ imported Greek artists, as they were seen as the best of their day. Ridgway referred to their style as being less bland than the Classical Greek style.

The Etruscans had an influence on Roman art, culture and politics. This is not surprising, as Rome is not very far from Etruscan territory and early in its history it was “just another city state” rather than being the juggernaut of empire that it later became. Early in Roman history they were even ruled by one of the Etruscan city states. Later however the Romans conquered and assimilated the Etruscans. As pointed out above, the Etruscans weren’t one cohesive unit so the Romans could conquer them a bit at a time rather than face all of them en masse. They had influence in the Roman political arena much later than one might expect, given they were conquered by Rome around the 4th Century BCE. The Emperor Augustus was supported during the civil war (preceding him becoming Emperor) by several old Etruscan families. These families were the aristocracy of the old Etruscan city states but had been assimilated into the Roman society and political elite by this point. However they were seen as a distinct and influential cultural bloc, that was necessary to get “on side” if you were making a power play. Later still Claudius was married to the daughter of one of these families (who persuaded him to write a history of the Etruscans, now sadly vanished without trace).

I knew pretty much nothing about the Etruscans before I listened to this programme, beyond the simple fact of their existence. I know the British Museum has a room displaying their culture, and this programme has made me want to have a proper look at it sometime.

In Our Time: The Augustan Age

The Augustan Age is the period between 27BCE and 14CE when the Emperor Augustus ruled the Roman Empire. It was discussed on In Our Time (in 2009) by Catharine Edwards (Birkbeck College, University of London), Duncan Kennedy (University of Bristol) and Mary Beard (Cambridge University). They were primarily considering the politics and arts of the Emperor Augustus’s reign and how these were linked. Politically speaking it’s the beginning of the Roman Empire and a period of peace after the instability of the civil war that marked the end of the Roman Republic. And in terms of the arts this period includes some of the names that one thinks of when one thinks of Roman literature: Virgil, Ovid, Horace.

The Emperor Augustus was called Octavian before he became Emperor and was the adopted son of Julius Caesar (so is sometimes referred to as Caesar). He was named heir in Julius Caesar’s will, but when Julius Caesar was murdered Mark Anthony tried to grab power and civil war broke out. When the dust settled Octavian didn’t restore the Republic, instead he became the Emperor Augustus and inaugurated the Roman Empire. He managed to leave the Senate a sense of dignity and respect (thus heading off the likelihood of an end like Julius Caesar’s) whilst actually retaining sole control himself. For instance he chose a role from the standard Roman Republic’s kit to hold in perpetuity (Tribune) that was actually one of the more junior roles but it was also the one that spoke first in the Senate allowing him to direct the proceedings. He also made a point of knowing all of the Senators, and Beard said that he’s supposed to’ve greeted them all by name at the beginning of each session – which, as she pointed out, must’ve come across as rather fake & tedious to the Senators who weren’t whole-heartedly buying into the cult of Augustus.

His propaganda characterised his reign as a return to the good old fashioned Roman virtues – a bit like the Tory Party narrative of “family values” in modern politics, looking back to an idealised 1950s that never was. Augustus cast the civil war and turmoil as being the result of Rome and the Roman citizens’ fall from virtue over the preceding decades. The bedrock of Roman virtue is the mythos of the farmer-general who leaves his plough to lead the armies of Rome to glory. It’s rooted in rural and agricultural life, and military values; and this is juxtaposed with the sins of decadent urban life where citizens live in luxury. Which I found quite amusing as the way we remember the Roman Empire includes quite a lot of salacious scandal about “my goodness what those Emperors and their families got up to!”. And it seems that Augustus would be horrified by this image of his Empire. He envisaged his family’s role as playing the part of “Good Old Fashioned Roman Family” as an example for everyone else to live up to. For instance his wife spun the cloth that made his clothes, just as a good Roman housewife should. He was not entirely successful in achieving the family image he intended (see below), but he did succeed in successfully re-inventing himself. Which was quite an achievement, as during the civil war Octavian had been somewhat of a young thug. There are multiple stories of his ruthlessness and cruelty, including one tale of him ripping out someone’s eyes with his bare hands! Not quite the good and virtuous first-amongst-equals farmer-general of his later propaganda.

One of the things Augustus does to return virtue to Rome is to pass new laws enforcing proper moral behaviour. Notably these included laws against adultery. This was the area in which his family fell short of the image he was hoping they’d convey. Augustus’s daughter Julia had been married off “advantageously” but clearly not to her tastes – she committed adultery in a particularly noticeable and notorious fashion. Augustus was forced to take action using his own laws, and she was exiled and some of her lovers executed. Then a decade later Julia’s daughter (also called Julia) went on to do much the same thing as her mother – with much the same consequences. So much for the Good & Virtuous first family!

Augustus poured money into the city of Rome – he is said to’ve come to Rome as a city of brick and left it a city of marble. His building projects were wide-ranging and numerous, and many of the buildings we think of as Ancient Rome come from his infrastructure overhaul. This is notably not a return to the “Good Old Days” – we listened to an In Our Time episode about the Roman Republic about three weeks after we listened to this one, and it made the point that the ephemerality of power was a key concept in the Republic. So building infrastructure out of ostentatious and permanent marble was a change of paradigm, reflecting the difference between Republic and Empire as governmental systems.

The flowering of literature and poetry during the Augustan Age is tied into Augustus’s propaganda machinery. It’s a part of the return to the old virtues and of the idea of making Rome great again. Augustus was definitely a patron of the arts – it’s not known how much he paid the writers, but there’s evidence that he did pay them, and pay them well. He also writes some of his own poetry, but there’s no evidence one way or the other about whether or not he also “collaborated” on the others’ poetry. Some of the well known works that survive to the present also have Augustan propaganda as part of their subject matter. For instance Virgil’s Aeneid has a section early on where Jupiter prophesies the future of the city Aeneas has founded (which is Rome). This details the future of Rome through to Augustus as the necessary, pivotal and inevitable Emperor, after whom Rome will rule the world forever. It situates everything Augustus did to gain power and how he is now ruling as the things that are necessary for the future glory of Rome (rather than self-serving). Augustus also traces his ancestry to Aeneas (just like medieval English kings will later link themselves to Brutus and/or King Arthur).

Horace’s poetry is also a part of the propaganda machinery (on the family values side of it) but Ovid is less obviously a part of this. His work is lighter and more comedic than the other two poets, and much more about sex than the new morality of the Augustan Age is really comfortable with. There’s also evidence that Ovid himself didn’t sit comfortably in this new morality – he was perhaps a part of the Younger Julia’s disgrace, and was exiled from Rome. He missed Rome while in exile, considering it the only place worth living – even if his work was more light-hearted than the tone of the age, he was still very emotionally invested in the new Rome that Augustus had built.

Near the beginning of the programme they mentioned the Elizabethan Age (of Elizabeth I of England) as a way of explaining the term “Augustan Age”, and once one’s mind has been drawn to it there are some coincidences in more than the terminology we use for the era. Both are periods of calm after a period of chaos and disunity, the leadership of each country is presented as benign yet is actually pretty tyrannical, both have a flowering of literature which is state-controlled propaganda as well as art. And Elizabeth I was crowned on nearly the same day as Augustus took power (only 1585 years and 1 day later…).

In Our Time: Frederick the Great

I’d heard of Frederick the Great before I listened to this In Our Time programme about him – I knew he was an 18th Century ruler of Prussia, and I knew he was a flautist (having seen a painting of him playing the flute). What I wasn’t aware of before was that he was obsessed with being famous, and had quite serious Daddy issues. The experts who discussed him on the programme were Tim Blanning (University of Cambridge), Katrin Kohl (University of Oxford) and Thomas Biskup (University of Hull).

Frederick was born in 1712 and had what sounds like a rather appalling childhood. The first part, until the age of 7, when he lived in his mother’s court was the better part. It was during this time that he acquired his interest in and love of literature, philosophy and the arts. He also forged a strong bond with one of his sisters in particular – so much so that in later life he built a temple to friendship for her with a statue of her in it. But the court was full of intrigue and he and his siblings were frequently pawns in the schemes of various factions. So as well as the arts he also learnt to live his life on display and to cultivate an image that he wished to present to the rest of the world.

His later childhood and early adulthood were spent at his father’s court. Frederick Wilhelm I was a parsimonious Calvinist, a pious, frugal man who was also keenly interested in military matters. He had spent his reign building up Prussia’s military and treasury. His son shared none of his interests nor his Calvinist virtues and resented the pressure to become a chip off the old block. Frederick Sr would abuse his son both in private and in public, by beatings and by humiliating the young man. During his teenage years Frederick once attempted to escape his father’s court. He and some friends concocted a plan to escape from their military assignment and flee to Britain – the experts described this as a fiasco that failed almost before it began. Frederick and one of his friends were captured and locked up. For some time Frederick was allowed to believe he would be executed for desertion – this (obviously) did not happen, but his friend was executed. Frederick was forced to watch this execution which left him somewhat traumatised – the friend was someone Frederick was very close to, perhaps even his boyfriend.

Summing up this section the experts all agreed that a childhood such as Frederick had has the potential to be psychologically damaging – and that in Frederick’s later behaviour there is evidence that he was indeed damaged by it.

When his father died in 1740 Frederick inherited the throne of Prussia. At the time Prussia was too big to count as a minor European state, but too small to be a major power. It did, however, have a fantastic military and a large treasury – due to Frederick Wilhelm I’s frugal military obsessiveness. However the military hadn’t actually been used – and so practically the first thing Frederick did on coming to the throne was invade Silesia, in part to prove himself a mightier man than his father. It wasn’t just a response to his Daddy issues – it was also an astute political move. At the time the Hapsburg dynasty was undergoing a crisis so it was a good time to try and snap up a few territories whilst they were otherwise occupied. Silesia was near Prussia, and rich, so a good choice for Frederick. The initial campaign went very well, and this was the beginning of several military campaigns. By one point Frederick’s Prussia stood almost alone against all the other powers of Europe who had allied against him – his only ally was Britain. Despite being vastly outnumbered Prussia had the advantage that Frederick was the sole decision maker and was actually on the scene. The other countries all had different aims, which hampered co-ordination between them, and they had to send communications long distances between the commanders on the field and the decision makers at home. Although of course this advantage for Prussia could also backfire if Frederick’s decisions were unwise!

Napoleon regarded Frederick as a great strategist – I imagine he saw Frederick’s standing alone against the other European powers as mirroring his own situation. However the experts were firm in their disagreement with this assessment – one of them (I forget who) dismissed it with the words “Napoleon was wrong about a lot of things”! The consensus was that Frederick was a great warlord – charismatic and capable of leading his troops – but not a particularly good general. Frederick’s brother was a better general, and never lost a battle – however he would’ve lost Silesia in the first campaign by (sensibly, based on the situation at the time) taking the peace deal that involved handing the territory back. Frederick had the drive and desire to win at all costs, and because of his charisma the army would follow him and he lead them to greater gains.

One key success was the capture of West Prussia. The kingdom that Frederick inherited was made up of two geographically separated territories and annexing West Prussia made his country contiguous. In retrospect this was the beginning of the partition of the territories making up Poland between the surrounding countries until there was no Poland left.

Frederick was obsessed with gaining fame and status – he wanted to be remembered himself, and he also wanted Prussia to be a major player in European politics. After the successful campaign in Silesia he instructed the media to refer to him as Frederick the Great (which was a successful PR move as we still refer to him like that today). He carefully crafted other aspects of his image to gain recognition. His patronage and participation in the arts was partly driven by this. He wrote poetry in French which was rather conventional, and whilst not bad it was also not good either. He also, as I mentioned before, played the flute. But art was not just a matter of image for Frederick, it was also his spiritual core. He was not religious himself, and was scathing about religious belief. Art and music were his ways of connecting with a sense of transcendence. He wasn’t, however, particularly interested in German language literature – and the experts said his primary influence in this area was ignoring it enough for independent thinkers to flourish.

His court was renowned for its tolerance and for being a centre of learning. Of course that’s tolerance in a very 18th Century sense – in this case in particular it meant that philosophers who spoke against religion were welcome there after their own countries had hounded them out. Courtier for a while at Frederick’s court was Voltaire – one of the most famous philosophers of the age. He corresponded with Frederick for decades – he was older and something of a mentor to Frederick, including correcting his French (including his poetry). Like Frederick, Voltaire was keen to gain fame and be remembered, and the two collaborated on polishing each other’s images. Despite the long running correspondence Voltaire was only at Frederick’s court for a few years. In person the two big egos did not get along as well as they hoped. Frederick didn’t treat Voltaire with enough respect for Voltaire’s tastes. And Voltaire got mixed up in shady business dealings that embarrassed his host. After 3 years he moved on, but they kept corresponding.

Frederick was almost certainly gay. As I alluded to above his father executed a man who was perhaps his boyfriend whilst Frederick was a teenager. Frederick did marry – a match arranged by his father, and initially it was probably welcome to him. It meant that as a young adult he was able to set up his own court (as a married man) rather than continuing to live in his father’s court. However once Frederick’s father died he had no incentive to continue the charade – the two never lived together again. I don’t think they talked on the programme about what Frederick’s wife thought this (it would be a bit off-topic). She kept court in Berlin after they separated – which was the capital of Prussia, so needed a royal presence. Frederick hated the city (his Daddy issues rearing their head again) and so he had no inclination to live there himself. The experts felt reasonably sure that people at the time were aware of Frederick’s sexuality. The terms “gay” and “homosexual” didn’t exist in their modern sense, but his favourites were referred to as being “like a royal mistress” which implies awareness of his intimacy with them.

Ultimately Frederick was successful in his search for lasting fame. He has been remembered since his death in 1786 as the man who put Prussia on the map. Over the years various groups have held him up as an icon or hero – for his tolerance, for his military successes, for the arts, for the sciences, for pushing on at all costs, etc. After the Second World War (and Hitler’s appropriation of his image for the Third Reich’s propaganda) his star dimmed somewhat, but there has been a more modern resurgence of interest in him. The programme ended with the note that whilst he’s nowadays held up as a proto-Bismarck and pre-figurer of a united Germany, he regarded himself as a Prussian nationalist not a German one.

In Our Time: Extremophiles

“Extremophiles” is a bit of a parochial term – this is the name for organisms that live happily in environments that we consider extreme. Too cold, too hot, too acid, too something to support life, in our terms. Studying the lifeforms that disagree with us on what is a good place to live has started a new field of astrobiology and a new appreciation of the possibility of life existing in the wider universe. Discussing this on In Our Time were Monica Grady (Open University), Ian Crawford (Birkbeck University of London) and Nick Lane (University College London).

The study of extremophiles started with the discovery of a rich ecosystem based on extremophiles living at hydrothermal vents in the sea floor near the Galapagos Islands (an amusing coincidence that it’s these islands in particular). The discovery was made by the scientific crew of a submersible called Alvin in 1977, and was a revelation as although extremophiles were known to exist this was the first evidence that there were more than a few outlier species. Previous assumptions about the requirements for life were shaken up by this discovery. The experts emphasised that we (and organisms like us) live in the “extreme” environments when compared to the universe as a whole – we require conditions that generally don’t exist. So the discovery that life could exist in more “usual” conditions meant that it’s more plausible that life might exist somewhere other than on Earth.

The science of astrobiology was started by these discoveries – this is a multidisciplinary field, which the experts positioned as being part of a trend in modern science. The 20th Century was in many ways about increasing specialisation in the sciences, but now there is a move towards seeing the bigger picture with more collaborations between groups with different specialities. Astrobiology is not exobiology – that would be the study of alien lifeforms and we haven’t found any (yet). Instead astrobiology is the search for life elsewhere.

One of the assumptions that was overturned by the extremophiles found by Alvin was that sunlight was critical for life. Knowing that it’s possible for life to cope with no sun* opens up the possibility that life might exist on Jupiter’s moon Europa, for instance. Europa has a hot core (due to the friction generated by the various gravitational forces exerted on it) and an icy shell, with liquid in between. It also probably has hydrothermal vents. It just wouldn’t have sunlight under the shell, but that might not matter after all.

*They did mention in passing later in the programme that parts of the ecosystem at those vents makes use of the oxygen dissolved in the sea, which wouldn’t be there without sunlight (as it’s a by-product of photosynthesis, which uses the sun for energy). So the current population is evolved to handle a post-photosynthesis world. But I think the idea is that if there wasn’t any dissolved oxygen then it’d just be a different ecosystem of extremophiles rather than no ecosystem at all.

Another foundational insight for the field of astrobiology was the work of Carl Woese in the 1970s on developing a Tree of Life based on genetic data. The traditional view of the high level groupings of organisms is five kingdoms: animals, plants, fungi, protists, bacteria. But Woese’s work showed that the real high level division is into 3 kingdoms: bacteria, archaebacteria and eukaryotes. Eukaryotes include all multicellular organisms (plus some single celled ones). Archaebacteria include the extremophiles and were once thought to be just a subset of bacteria – but the genetic data shows that they are as unrelated to bacteria as we are. They also arose first – bacteria and eukaryotes diverged from them later.

Astrobiology is not the same as SETI – the latter is searching for signs of intelligent life elsewhere in the universe, but astrobiologists will be overjoyed to discover a single celled organism existing somewhere other than Earth. The experts spent a bit of time discussing the Drake Equation and how astrobiology fits within that framework. The Drake Equation is an answer (of sorts) to the question of how many extraterrestrial civilisations we might be able to communicate with. I say “of sorts” because, as Bragg pointed out on the programme, the terms of the equation started out as all unknowns. What the equation is useful for is breaking down the question into manageable chunks that can then be investigated. So one term is “how many stars have planets”, and since Drake formulated his equation it’s been found that pretty much all stars have planets – so clearly that’s not a limiting factor. The question that astrobiologists are working on is “how common is life of any sort?” – which is a couple of the terms in the Drake Equation: the average number of planets that are capable of supporting life per star that has planets and the number of these capable planets that actually develop life.

There’s still only one example of a life-bearing planet, so it’s hard to extrapolate much about the origins of life and how common an occurrence it might be. One thing that might have bearing on the problem is that life only arose once on Earth – all organisms share a common ancestor. I did wonder, although they didn’t discuss it, if we can be sure it only arose once – is it possible to disambiguate that from multiple origins only one of which survived? But even if we are sure that it was a one-off event on Earth this may not be because it’s hard to do per se. It might be that once life gets going once it uses up the raw materials that it arose from, preventing subsequent developments of life. This is an idea that goes back even to Darwin although other parts of his “small warm pond” concept of the origin of life are no longer thought plausible.

The origins of life aren’t the only thing that we only have one example of on Earth (with relevance to the Drake Equation). The jump from the simpler cells of archaebacteria and bacteria to the more complex cells of eukaryotes has only occurred once. Multicellular organisms have also only evolved once, ditto intelligence capable of building a technological civilisation. So even if it turns out that there are many planets supporting life of a sort out there in the universe, intelligence may still be very rare or even unique.

Panspermia is another hypothesis about how life got to Earth – or conversely how it may have got/will get to other places. This is the idea that life is spread through the universe via meteors etc, and so life may not’ve originated on Earth. There are several things that suggest that this is possible, even if we don’t know if it actually happened. For instance we do find bits of rocks on Earth that originated on other planets (the Manchester Museum has a small piece of the Moon and a small piece of Mars that got to Earth as meteorites). There are also micro-organisms on Earth that can live within rocks. And we know from experiments done on space missions that some micro-organisms can live through the heat of entry into the Earth’s atmosphere. At this point in the discussion Bragg mentioned Fred Hoyle had been laughed out of the scientific community for proposing something similar many decades ago. Grady pointed out that one reason this sort of theory is looked down is that all it does is shift the question up one level: What’s the origin of life on Earth? Space! What’s the origin of life in space? Dunno. The modern concept of panspermia is also not the same as Hoyle’s – which involved free-floating life seeds travelling over large distances, rather than accidental transfer between planets via meteorite. (This whole section of the discussion made me think of the start of the film Prometheus, which of course is another reason people raise their eyebrows at panspermia – all too often it comes with a side order of “and that’s how the aliens made us”.)

Finding life on other planets is made more difficult because we don’t entirely know what we’re looking for. There was a meteorite discovered in Australia that was thought might have fossil micro-organisms in it that hadn’t originated on Earth. Eventually it was decided that these weren’t the first signs of extraterrestrial life, but it was controversial for a long time. Grady noted that it was easier to figure out in that particular case because it was a rock that had landed on Earth – the task gets much more difficult when another sample means another round trip to Mars. However the only way we’re likely to find out if there’s life elsewhere is by going and looking – whether that’s with robotic explorers or human explorers.

As the Australian meteorite case shows there is a high level of proof required before astrobiologists will be willing to agree that they have found signs of life that are definitely of non-Earth origin. However the experts felt that they (as a field) are getting better at figuring out what to look for. The essential requirements for life are now thought to be water and carbon, but even with those requirements in common with Earth life extraterrestrial life might look very different. The experts emphasised how much chance is involved in evolution – even if you could re-run the history of the Earth it would look completely different despite starting with the same conditions.

This programme felt oddly mis-named – not often the case for In Our Time episodes which generally stay on topic rather well. But this wasn’t really about extremophiles, it was about the search for non-Earth life.

In Our Time: Aesop

Aesop’s Fables are so deeply embedded into our culture that references to them are common parts of the language – “sour grapes”, “crying wolf” and so on. But we don’t often think about who Aesop was, where these stories originated or what the point of them is – or at least, I certainly didn’t! Discussing Aesop and the fables attributed to him on In Our Time were Pavlos Avlamis (Trinity College, University of Oxford), Simon Goldhill (University of Cambridge), and Lucy Grig (University of Edinburgh).

Aesop almost certainly didn’t really exist. He’s a myth or archetype in a similar fashion to Robin Hood – there’s a general shape to the myth but the other details often vary. What Aesop has in common across all references is that he’s ugly, he’s a slave, he’s clever and he speaks truth to power. Even the earliest mentions of Aesop say he’s been dead for a century – he’s a mythic figure from the past whenever you are. One of the most complete stories about Aesop himself that we have is a story from the 1st Century AD called the Romance of Aesop. In this narrative Aesop is an ugly slave whose master is a philosopher – but he frequently outwits his master. For instance his master goes to the baths, and asks Aesop to bring the oil flask. When Aesop does, his master asks why there’s no oil in it … and Aesop replies that he wasn’t asked to bring any oil! This sort of quickwitted trickery is the reverse of audience expectations for the story – after all, isn’t the master a philosopher who should be both clever and quick thinking? And outward appearances were expected to mirror the internal qualities of a man – so who would expect an ugly man to be clever? It’s also pretty subversive – lots of acts of petty rebellion which make the master’s life a misery.

Given that Aesop is probably a mythic character it’s unlikely that he actually wrote the fables he’s credited as the author of! They are most likely an oral tradition dating back to at least the 5th Century BC in Greece. It’s possible that they originated in Mesopotamia before that and if there was a historical Aesop then he was perhaps a slave from that region who told their fables to Greeks. The fables were written down later, but the repertoire changes over the centuries so there’s still an oral tradition running alongside the written one. During antiquity the fables spread from Greece to the Roman world and throughout the Roman controlled territories. They even got as far as the edge of China – there’s a version known that was written down in a Turkic language from Chinese controlled territory. In the Renaissance Aesop’s Fables were rediscovered and translated into many European languges, where they’ve remained current since. This rediscovery wasn’t limited to Europe – the new translations of the Fables spread to Japan as well.

Fables are a specific genre of stories – they are short, generally told with animal or stock characters with a moral attached. The moral doesn’t necessarily come at the end, it can be at the beginning or even in the middle. Different tellings of the same story can have different morals attached. And interestingly the moral doesn’t necessarily have to match the scenario in the story – the cognitive dissonance this causes can be part of what makes the fable memorable and/or useful. You do find the stories from fables turning up without morals, in joke compilations, but I think the experts were saying they don’t count as fables then. So what’s the point of these fables? They’re not just entertainment (although obviously that’s part of the point) – in modern times they’re children’s stories and that was always part of their use. They teach lessons about how the world works, in bite-sized and amusing chunks. The stories and morals are often about power relationships, approached from a bottom up perspective (and the Romance of Aesop is a sort of meta-fable fitting into this category). So they teach children (and adults) how to navigate a hierarchial society like the Roman one. In antiquity they might also be used by adults as a subtler and politer way of getting a point across to someone more powerful than oneself.

The programme finished up by considering the wider connections of fables – mostly this section was about how there are interesting similarities between Aesop & his fables and Jesus’s parables. The stories themselves are not the same, but they’re the same genre – short tales, with a moral, about power and told with a bottom up perspective. While I was writing up this blog post I also wondered if Br’er Rabbit fits into this genre – I can’t remember enough of any Br’er Rabbit story to be sure it fits the genre, tho.