AD 1500 was a period when Columbus was still considered fairly daring—it was only eight years earlier that he had made his voyage. I don’t think that anybody with any brains thought he was going to fall off the edge. Most educated people in 1492 were not flat earthers, but they did not believe there would be any land mass in the other hemisphere. Perhaps to sail on forever and not finding anything would be worse than falling off the edge and getting it over and done with.
Copernicus suggested that the sun was the center of the solar system. Shortly after Copernicus came, Brahae, the Danish astronomer, the first man since the ancients to get down to really systematic observations. Then Johannes Kepler, the mathematical genius who discovered something about the nature of comets, and later invented a set of five figure log tables to help himself with his calculations on the orbit of Mars. Someone in Britain had also discovered logarithms but Kepler had not heard of that. After 12 years of exacting work Kepler eventually discovered in very great detail the shape of the orbit of the planet Mars. Kepler was also one of the first men to look through a telescope. He sent his idea to Italy, and Galileo, a great publicist and very good propagandist, promptly claimed to have invented the telescope. Before the year 1700, we have Halley identifying Halley’s comet, the notion of the recurring comet, and of course, Newton.
In physics in that same 200 year period, Gilbert began work on magnets, and Torricelli discovered the significance of the vacuum and mercury barometer. A German invented a workable air pump and showed that if you pumped air out of a sphere it was very hard to pull it apart. Every time you put your foot on the brake of the car be thankful that Pascal’s Principle still operates. There was Hooke of England, who first discovered a general law of elasticity, and his friends Harrison, Newton and Christopher Wren. In the 1600s we had the beginnings of modern chemistry, particularly with Robert Boyle, sometimes introduced in textbooks as “the son of the Earle of Court, and the father of Chemistry.” He was the one who discovered one of the basic laws about the relationship of pressure and volume of gases. More than anything else in that period there was the establishment of that area of physics called mechanics—Galileo, Descartes and Newton.
Also the 1600s saw the founding of the great scientific societies. It’s an interesting debate as to which one was founded where first. But by 1661 you have the Royal Society very clearly chartered and established in England; by 1666 you have the French Academy De Sciences and others following a tremendous growth in the realm of what was called natural knowledge. The methods used in all of this hinged on two main things. First of all, this growth in scientific knowledge was dependent on observation. They went and looked at something. However, don’t get too carried away with the idea that all these people went in for observation. There’s a fair suggestion that Copernicus probably did about half an hour of actual astronomical observation in his life. He’s known to have recorded 32 observations, total. Some are pretty grim ones too, e.g. “the moon rose last night.”
Observation was the first factor, and secondly there was calculation. Mathematical calculation, mathematical demonstration. These two things, observation and calculation came to be seen more and more as the “royal road to knowledge.” Meanwhile the theologians were busy tearing each other apart both in word and deed. During that 200 years, the Huguenots wars in France, upheaval after upheaval in England and Scotland, and then the whole thing culminating in that glorious blood bath called the “thirty year war” in Germany. Supposedly something religious when it started, but the religious bit got lost somewhere and thirty years later the population of Germany was about half of what it was when the thing got started. Enthusiasm was gone, the “cause” was forgotten, and everybody called a halt. But it was still generally identified in those days as being a religious war. While that was going on in the realm of so-called religion or so-called Christianity, the scientific persons were using their scientific method to dramatically improve their knowledge. They had reached the stage where “somewhere above this vast and accurate realm of natural knowledge of the arts and sciences was the self decapitated strange aberration called theology.” The top had floated off the knowledge triangle completely.
But what about this scientific method? To see how this method works, let us look at Isaac Newton, the so-called discoverer of gravity. He didn’t really discover gravity. The first person to trip over a stone discovered gravity. What Newton did, however, was to show that a number of quite apparently different phenomena could be explained by showing they had one common factor. They were all special cases of the one sort of principle in operation. Newton didn’t just sit under an apple tree and say, “Apples fall off trees—I’ll call it gravity!” But rather, “Apples fall off trees for much the same reason as the moon goes around the earth, for much the same reason as the tides rise and fall and the comets travel in elliptical or parabolical orbits.” Now that was the clever bit. Who on earth would have thought that apples falling off a tree had anything to do with bright lights in the sky with funny tails on them? Whoever would have thought that apples falling off a tree in a garden in Wolfsburg had anything to do with the rise and fall of the tide in the Thames! We are indebted to Newton for showing how these different things were somehow related. Newton’s method was basically this—How can we explain what we know about X in the light of what we already know about some other things called Y and Z? All of this raises the interesting question as to what counts as an explanation.
A scientist does not just explain how things happen.
Most people think a scientist’s job is to explain things and to find why something happens. This common belief is so simple that it’s mistaken—fundamentally mistaken. A scientist does not just explain how things happen. The explanation, if you are working in Newton’s terms, is an explanation limited in many ways. It must relate a known observable to some other already known observables. This is what we have come to call a “scientific explanation.”
Now this is not the only type of explanation there is, but it became the basic style of the explanation the scientists used, and still use. It is quite interesting to read the early minutes of the Royal Society. The first few meetings were rather scientific as we would understand them, and then a few people started to want to talk philosophically and debate abstract concepts. To cope with this, the Society passed a rule which said that no one could read a paper in anything unless it was based on either calculations or demonstration. If they couldn’t demonstrate a fact or a calculation they were not to present a paper. They didn’t say it, but presumably any other type of paper was waffle and any other sort of evidence didn’t count.
Suppose there is a car accident on the street corner. A young constable gets sent out from the office and the sarge says to him, “Now look, when you go out to look at an accident, you’ve got to try and get the facts, get the evidence; get your notebook out and collect the facts.” So he does. He arrives at the street corner and begins to write. “It’s two days after Australia lost the Fourth Test. Two doors down the street there are three poppies blooming. Somebody thought they heard a lark singing that morning but they weren’t quite sure. Four doors the other way there is an office that always closes for lunch between 1 and 2:30. The little old lady on the corner didn’t get her mail delivered yesterday.” Now what would you think of him if he came back with all that as part of his information? You’d say, “Look, you’ve missed the point; you’re supposed to go out and look at things like whether the drivers were sober or drunk, whether their cars have balding tires or not, or their brakes work, or whether there were traffic lights, or whether someone was looking into the setting sun.”
But the constable might have been on the right track. The office closes between 1 and 2:30, and the accident occurred at two o’clock. The girl in the office had a row with her boyfriend because he was still grumpy after Australia losing the Fourth Test. So she went for a walk down the street and there at the corner she met a little old lady who was out looking in her mailbox for the umpteenth time because her mail didn’t come yesterday. She told the girl about the three beautiful poppies down the road and the girl bent down to look at the poppies as the driver went past, and that is how the accident happened!
What counts as relevant evidence in science? Well, by and large, I think we decide that by common sense, careful common sense. Nine out of ten car accidents are caused by brakes or drunk drivers or the setting sun. We would say that we know the usual factors that cause accidents, but the interesting question to ask about science is who decides that we know, and why we know?
A very interesting field of research today is a field perhaps best called the sociology of science. This is the study of why it is that scientists come to accept some things as relevant evidence and some things as irrelevant, some arguments as good ones and some as bad. The answers which have come to light suggest it is nothing to do with any conspiracies, neither has it anything to do with the fantastic or the odd. At least part of the explanation is this. Scientists have grown up in a certain kind of environment where they have been taught certain things and learned certain tricks of argument. Because they have developed in this sort of way they think along certain lines and they think along those lines very successfully. There is no more socializing experience in the world than attempting to write an honest paper on a Ph.D. thesis. You know that you’ve got to play the game out in a certain way, otherwise somebody will put the red line in the wrong spot. It’s a fact. It’s a fact of life, not because anybody is being malicious, but rather, being fallible human beings, they are a bit limited and when the young constable comes back with his report about poppies and little old lady’s mailbox, they laugh at him. In the same way, if you come up with something that’s too odd it is very hard to get it accepted. One of the great electrochemists of the late nineteenth century, Svante Arrhenius, spent literally years trotting around Northern Europe trying to find somebody who would accept his Ph.D. thesis, because he claimed there were positively and negatively charged particles in salt solutions all the time. As soon as you dissolved salt in water it broke up into positively and negatively charged pieces. It broke into sodium and chloride ions. Everybody looked at him and said, “Well it didn’t go green so there’s no chlorine in there, is there?” Finish; failed him. Literally, that’s what happened.
Do you see what is happening? Now to come back to the point. The scientific community in the sixteenth and seventeenth centuries began to become so very successful. In the hands of somebody like Newton it was supremely successful at explaining a whole lot of things, and it tended from that point on to informally enforce its own rules and at the same time give an impression, intentionally or unintentionally, that this was the royal road to truth. That “our” limited questions were the only ones that could be asked. That limited explanations and limited types of evidences were the only evidence or explanation that should be accepted. The Scientific Paradigm had arrived!
What do I mean by paradigm? Very briefly, a paradigm is best thought of as a very successful piece of work of some kind which has become a standard model against which all future work becomes measured. It becomes the standard. Newton’s Principia, his great work in physics became a standard, a model against which anybody else’s research was somehow measured. It is interesting to notice in the eighteenth century, in the hundred years after Newton, in a large number of different fields, people started to get enthusiastic about trying to explain other things in the same way as Newton had explained the tides and the apple and the sun and moon. For example, in France in the 1730s a young French author, a fellow called Lametrie, had to depart for the Netherlands in great haste. He did so because he had just published a book under the title L’Homme Machine’—Man, the Machine. It was an attempt to explain what a human being was in terms of ordinary mechanics. Man had a crunching device that crunched up food, a rippling device that somehow shook it up and presumably provided the little bit that went through the body, a bellows that sucked air in and out, warmth from some sort of slow combustion, levers and pulleys and an optical system. Man, the machine, argued Lametrie, was no more or less. He could explain a man in terms of simple mechanics. Just as Newton explained a whole lot of complex things in terms of his theory of gravity now here we can explain a human being in terms of mechanics. Not very successful, but it was an interesting try. It was successful enough to make the French authorities encourage his rapid departure to lesser regions.
The eighteenth century saw the beginning of modern economics, with Adam Smith and Company and their attempts to calculate economic flow. Maybe society could be reduced to a set of figures. The meaning of a social system could be understood in terms of observation and calculation a la Newton. Maybe ethics could be made scientific. Jeremy Bentham, the English reformer, believed it. What man needed, claimed Bentham, was a happiness calculator. “As long as we’ve got a happiness index we will be right!” All we have to do is figure out how many happiness points a certain legislation needs to make people happy, and then politics is successful. If it makes this number of people happy by five points, this small number unhappy by ten points, add it up, and conclude that it is worth doing because it increases the sum total of human happiness. Mind you, it was not a bad way of attacking the English Parliaments of William Pitt, the younger, which were defending the rights of five thousand landowning aristocrats against the other 15 million inhabitants of the land. But still, it became a theory, Utilitarian Ethics. Man could calculate how much happiness something produces. Everything can be calculated.
One of my favorite examples occurred towards the end of the eighteenth century. A French astronomer and mathematician, Pierre Laplace, worked out the so-called nebular hypothesis. In this theory the solar system began as a mass of hot gas which by rotating spun off the planets, leaving the sun in the middle. He also worked out the mathematics to show that it was possible. Laplace was granted the opportunity of an interview with Napoleon. Bonaparte was also very interested in mathematics. After all he had been an artillery officer, so presumably he had some sort of a flair for maths. Napoleon listened to Laplace’s theory and said, “It’s a magnificent hypothesis, but where does God fit into it?” Said Laplace, “Sire, I have no need of that additional hypothesis.” Well, that is an interesting piece of atheism. The funny thing was, Laplace was a good Catholic who went to Mass every Sunday. Two worlds! Between Monday morning and Saturday evening before confession, Laplace was the man of natural knowledge, the good mathematician. Saturday night, Sunday morning, dealing with the church he moved into the realm of faith. Two different worlds that didn’t meet. I venture to suggest that most of us tend to accept this view a lot of the time, even if we are not really conscious of it. We tend to work in a two-world system whereby we do not ask and we do not expect that what we label as religious questions or questions of revealed truth have anything to do with about 90% of everyday life. We tend to assume that in the real world of everyday things these are somehow divorced.
“Oh boy, here is a madman! The next time his car breaks down he’ll be flicking desperately through Exodus to try to find out where the spark plugs are.” Is that what you are thinking? I want to make very clear the point that because this does sound terribly mad to us, that because we think we can see very clearly the separation between spark plugs and Exodus, that we probably can’t see quite clearly what is wrong with this separation of natural and revealed truth. But where does this get us?
In the nineteenth century what were the range of scientific interests? By about 1800 it would be true to say that in the area of physics and chemistry there was a feeling that while it might be interesting for a physicist or a chemist to believe that there was a creating God, it certainly wasn’t essential and it had nothing to do with what he was doing as a physicist or a chemist. The Christian chemist and the atheist chemist could meet and discuss their points of view on chemistry with total neutrality and no real problems. There was still a problem area when it came to living things because living things were not quite so susceptible to simple explanations at that point in time, despite the attempts of Lametrie and others. But during the first half of the nineteenth century, a rapid spread of new discoveries threw some sort of light on the nature of living things. Not entirely but enough to get on the way, for instance, some of the chemists began to have some success. Justus van Liebig in Germany, got to the point of being able to roughly calculate how many different chemical elements made up the human body. He was the fellow who first worked out what a human being was worth if you broke him down to the constituent elements.
Another German physicist and physiologist, Helmholtz did some work on nerve conduction speeds. It used to be believed that nerve fibers transmitted information instantaneously. Helmholtz showed that there was a distinct delay in time. It took a measurable fraction of a second for information to travel along a nerve fiber. Now that meant maybe, the difference between people who are quick in their actions and slow in their actions isn’t something to do with their innate minds or whatever, it is just something to do with the fact that their nerve fibers are different.
By the 1840s in Germany, at least some people were quite confident that human beings could be explained almost entirely, or entirely, in terms of basic physics and chemistry. Let me give you two examples of the extreme sort of views. One chap was called Carl Bogt, and he came up with this immortal statement: “The liver secretes bile, and the brain secretes thought.” Fairly hard-nosed materialistic explanation, isn’t it! There was another chap called Buchner, Ludwig Buchner. His great effort was a book called Graft und Stoff, Force and Matter, the argument that everything consists of either energy or matter, and he wrote edition after edition after edition in the second half of the nineteenth century. Everything consists of energy and matter, that’s all! Why was it that these people were coming up with these sort of advances? I suggest the major reason why this was done was that the answers they wanted to the questions they were asking were a very special kind. Go back to Pierre Laplace in the eighteenth century, the man who said, “Sire, I have no need of that additional hypothesis.” Basically, what Laplace said was this: “How can we explain the solar system in terms of the physics and the mathematics that we presently understand without any assumption of supernatural intervention? How can we explain the world in natural terms only?” On those terms his nebular hypothesis can fit very nicely. In the nineteenth century the scientists were doing much the same thing without being anywhere near as honest. They were really saving, “Given that the natural is what we can know, how can we explain everything in terms of it?” This outlook has become basic to what is called the scientific explanation.