John March-Russel
Some thoughts about modern science
John March-Russell formerly a CERN theoretical physicist now working at Oxford University, who has been working on theories which question the fundamental nature of space-time.
[disc 3] When I wanted to go to university, my uncle asked me, well, what is it useful for? I was interested in physics and he said can you fix my TV? I said no, I'm sorry, I don't know who to fix your TV. He said, well, after you've gone to university and had all this education, will you be able to fix my TV then? And I said no, sorry, it's not very practical. So I have to admit, what many physicists do, especially my kind of physicists is to be a theorist. So the type of physics that I do is not very practical. It's very removed from every day concerns. Sometimes it addresses some of the issues that Gustav was raising about the fate of the universe or the birth of the universe, things like that. So rather than tell you those direct things, I thought I would tell you a storey and you can draw your own conclusions from this story, and the story concerns Galileo.
As you know, Galileo was probably the creator of modern science, more than just modern physics, but modern science, the scientific method. Early on in his career, he was employed by the Dukes of Florence on a certain project. In Florence at that time, Dante, who was a Tuscan native, had a very high status. And Dante described his idea of what hell was like. This idea of hell actually ad a very long prehistory which went back to the Romans and before, and their idea of hell was that you had the various circles of hell as big chambers, and these big chambers were underground.
[1.46] The idea that people had in Florence at that time is that they were rather like cathedral chambers, the interior of cathedrals, with big arches things like this. And they knew a lot about constructing cathedrals on the size of 50 meters tall and 20 meters across and things like that. But what they wanted to know is whether the descriptions of hell in Dante and the Romans and other people like that, could be real.
[2.14] They wanted to know, and they asked their scientists at the time and one of their best young scientists was Galileo, to calculate. Could it be true that under the surface of the earth there were large arches that would be self supporting. They knew the problem of cathedrals could collapse under their own weight. And so Galileo was set the problem of solving this by the Florentines. And he came up with the answer that yes, you could indeed build an arch that could be that large and some one 7th the size of the earth, made of rock, he knew the strength of rock approximately and things like this.
[2.54] Now it turns out that his answer that yes you could have this structure under the earth, was incorrect. And he discovered this later on in his career when he was at Padova University which is very near Venice. Venice was a very big, major trading and military power at the time, and they were concerned at the time, with building ships. They had both merchant ships and also military craft, and they wanted to know whether they could use the same design but just scale it up to a bigger size. So it's a very similar problem but the Florentines wanted to know could you have a cathedral arch but instead of the size of a cathedral could it be some fraction the size of the earth, and the Venetians wanted to know could you have a ship design, but make it twice as big, have twice as many guns, carry so many more times materials across the Mediterranean.
[3.50] And Galileo at that time introduced 2 techniques:
1. He was the person who really introduced the idea of using mathematics into the description of science.
2. He was the person who both gave modern science its power, partially because of that but also made it obscure for most people.
Before Galileo, the way that most scientist of philosophers would argue was in words.. They would do word problems, I'd give you a story or tell you how something would go and then you would give me a counter story.
[4.18] He was the person who decided mathematics was the language that science should express so if you find science obscure, you should blame him. Partially through this use of mathematics, and partially because the Venetians really cared about this answer. And they could go check. They could build a ship to this same design but just make everything twice as big and they would know whether it would collapse in their dry dock as they were building it. They really cared.
[04:56] Partially through experimental technique and partially through these sort of things, Galileo investigated what he had done before and came to the realisation that he was incorrect, no you couldn't build a cathedral arch some fraction the size of the earth. The reason for this is very simple, it's actually the reason for instance why there's a limit to the size of land animals, why the largest animals are only a few times bigger than the size of elephants, things like brontosauruses and things and that's the reason, that if linear extent, if you make an object twice as big in linear extent, like in height, imagine I increase my dimensions in every way by a factor of 2, how much does my weight go up?
My volume goes up by a factor of 2 times 2 times 2, it's cubic. So my weight goes up by a factor of 8, but hw about the strength of my bones, or the strength of my muscles? Well, they are determined by the area of my bones or the area of my muscles. And they only go up for times as much, 2 by 2. So inevitably, as you get structures bigger and bigger, their bones get relatively weaker and weaker, compared to the weight they have to carry and will break.
[05:49] That's why land animals, or at least land animals that have to move and actually really carry their weight on their legs and things like this, are limited to the size of only a few times bigger than elephants. It also explains why you can't have very large cathedral arches, they would fall under their own weight and explains why when you build up a ship you have to use a different design. And he realised this.
[06:19] Now, there are some interesting morals. This was a study and he was the first person to realise or think of the idea of how the physics, or the engineering of the situation change as you change the size of an object. And that is actually very important to modern physics and to modern science. Everything from atomic sizes to the size of the universe, and it may it may interest you that the theory you described, atoms, is also our best theory for the universe, the birth of the universe, the future of he universe, things like that. It's the influence of his ideas on modern science.
[6.59] But there's a second thing, which is that, why did the Florentines want to have this answer? And what answer did they want? Well, they wanted it because Dante was a Tuscan, he was considered one of the greatest Italian writers of the modern age, meaning the post Roman age, they wanted his views verified. They wanted to believe that it was not just a story but a reality.
[7.31] They wanted the answer 'yes' and Galileo was at a young, early stage in his career. So there was a lot of pressure on him. They didn't really care what the answer was, they just wanted some expert to come along and say yes, you're quite right, you should believe in Dante.
[7.45] That's one thing you should think about. The Venetians on the other hand, had a very practical interest. Could their ships survive storms, could you build them in the dry docks. So it's only later on, under that practical influence, that you come to the right answer. So, the first thing is that it's very easy to get the wrong answer or to be persuaded of the wrong answer, even if you're a very bright and very good person as Galileo was, and Galileo you should know from history was willing to stick his neck out, willing to risk torture from the inquisition, not that he really suffered that, but certainly imprisonment, loss of privileges, equivalent to what maybe Sacrolov underwent in the Soviet Union. He had high status and he was wiling to loose it later on in his career.
[8.30] Nevertheless, he was persuaded of the wrong answer, he persuaded himself of the wrong answer and others of the wrong answer. Another thing is that there has been a strong and valid to think about criticism, of science in general in the last 20 or 30 years, saying that science is very culturally specific, gender specific - most scientists are as you know, at least in Anglo Saxon countries, are male. That's actually not true in Italy or Spain interestingly enough, it's about 50-50 there. That's an interesting fact in itself. Anyway, there has been a big criticism of science that it's culturally specific. And I think the answer that scientist would give is the following:
[9.14] That the answers you get, given a question in the end if you pursue it enough, and pursuing enough is very important because you can get the wrong answers initially for all these cultural reasons, financial reasons, etc. in the end you'll get the same answer. But the questions you ask may be different. So indeed the questions that were asked of Galileo were determined by cultural prestige, artistic interest in many ways, and then later on financial interest and military interest. But it could have been a very different set of things, he could have grown up in a very different society.
Let me give you an example of a different type of question. The medieval philosophers you may have heard, cared about this question of how many angles can fit on the head of a pin. And this was always given as a typical stupid question, why did those stupid people even think about those things? They weren't stupid people at all, what does that question mean? That question is a question about the nature of the infinitesimal, which is a very important question in mathematics. That was really only investigated deeply in the 19th century and the 20th centuries. But it's a very different type of question from can you build materials of a certain strength, can you double them up?
[10.24] So at different periods, in medieval times they asked one type of question, in post renascence period they asked a different type of question. So the science you can get out, does depend on those cultural issues, which I think is an interesting thing.
[10.42] The type of science that we do now, hopefully the good scientist, or many good scientists working against each other or competing in some way will get to the "correct answer" or a good approximate answer in the end. Because time is short, I'll finish there, I won't go into more details, this is a sort of summary of what the thing is. I'd like to give you some time, just like Gustav did, which I think is a good format, of asking questions or discussing or whatever. I hope that was slightly interesting. So are there any questions?
[11.20] Questions not recorded
[19.15] At which point, the audience spontaneously and voluntarily moved their chairs into a circle and multiple open discussions occurred. It is deeply regrettable that the recording equipment was not set up to record these discussion. However, it is vastly more positive that a little bit of organisational prowess can and did trigger such extensive open discussion between people of different disciplines. We only hope that this series of talks might inspire more people to organise such open minded symposia.
Last updated on 18th February 2007
