Читать книгу Your Body - The Fish That Evolved - Dr. Keith Harrison - Страница 6
ОглавлениеI n this book, we are going to explore the history of the human body. As everything we shall meet has been discovered by generations of scientists, it is worth taking a minute or two to consider what exactly this thing science is.
The word ‘science’ is just Latin for ‘knowledge’ but throughout history the way people have decided what they know about the universe hasn’t always been constant. In medieval Europe, scholars would observe the world around them and theorise about why it was the way it was. They would then gather and debate their theories in an attempt to persuade others of their viewpoint. This convention of arguing the way to an agreed explanation eventually went out of fashion to be replaced in the 17th century by the rise of the scientific method.
The scientific method is an approach to understanding which we can visualise as a triangle. First, we observe the universe (or more usually the part that interests us). Next, we devise a theory to explain what we are seeing – a hypothesis. So far, this does not differ from the old approach but now a new step was added. Instead of arguing about the strengths and weaknesses of the theory, we test it in some way, usually by carrying out a form of experiment. When we view the result of the experiment, we are back at the beginning of the triangle, again making an observation.
The Scientific Method
We can go round this triangle as many times at it takes to convince ourselves that we finally understand what is happening, modifying the theory and devising new tests each time.
The scientific method now predominates in most cultures but it was not a new invention. It was simply an extension of how we live our everyday lives. For example, imagine you are walking down the street and see a fist-sized fuzzy brown ball on the path ahead of you. This is an observation (Step 1). You wonder what it is and speculate it might be a small coconut from the nearby market. You now have a theory: ‘It’s a coconut’ (Step 2). You bend down to examine the ball and you roll it over with your foot. You are now conducting an experiment to test the theory (Step 3). As you observe the result of the experiment (Step 1 again), you are startled to see the ball spring to life and scamper off towards some bushes. Your theory was wrong so you devise a new theory: ‘It’s a small animal’ (Step 2 again) and follow it to see if you can find out more. Whether you know it or not you are using the scientific method. You are a scientist. We all use this technique virtually every day. We can’t find our keys but think we left them in the pocket of the jacket we were wearing last night, so we go to look – observation, theory, test. We are all scientists and always were. Today, people tend to reserve the word science for particular academic activities to which they give technical names – astronomy, geology, chemistry, genetics and dozens more – and they call people who are paid to use the scientific method in their jobs ‘scientists’, but in reality we are all scientists.
Since the 17th century, the word science has acquired an aura of mystique but this is a misunderstanding. Science is not at all mysterious; it’s just that triangle. Two things make it seem impenetrable. First, the subjects the professionals study are often very complicated (‘How are stars formed?’ ‘What is inside an atom?’ ‘How can continents drift across the surface of a solid Earth?’) and, second, every branch of science has its own technical jargon which means nothing to us and may leave us feeling excluded and threatened.
When scientists study complicated subjects like star formation, they break the topic down into hundreds of different observations and hundreds of simple theories then test each theory. Sometimes, they need complicated equipment to test their simple theory but ultimately it’s only the technology and the overall subject that are complicated. As for the jargon, virtually every branch of human activity has its own vocabulary. Who can understand what a motor mechanic is talking about or name all the tools used by a carpenter? At least in those cases, other motor mechanics and carpenters stand some chance. Science is such a broad subject (or in truth many broad subjects) that few scientists understand what other scientists are saying even within their own discipline. A biologist studying bird classification and a biologist studying bird physiology may as well come from different planets. Neither will understand the other’s technical terms, and they are both biologists working with the same group of animals. Science should not be seen as a coherent activity with ‘insiders’ and ‘outsiders’. Most professional scientists find out what is happening in most of science from the newspapers and television, just like the rest of us.
What is not science?
Some subjects don’t fall into the category of science because they are impossible to fit into the science triangle. For example, our observations of the world may lead us to theorise that there is a higher spiritual power, a god. We therefore have two limbs of the triangle: an observation and a theory to explain it. The problem arises when we try to devise a test. What experiment would test the theory ‘There is a god’? To date no one has ever thought of one. Religion, therefore, is not science.
It has been argued by some people that science is antagonistic to religion and promotes atheism. This is not true. The results of scientific activity do not, and could not, imply there is no god. That would also require evidence from an experiment. As the old saying goes, ‘Absence of evidence is not evidence of absence.’ Science simply cannot investigate, and hence has nothing to say about, the existence or non-existence of a god. These are matters of faith. A self-professed atheist is just as much a believer as is a bishop. A bishop believes as an act of faith there is a god; an atheist believes as an act of faith there is no god. Science cannot help either of them. Science is necessarily agnostic (from the Greek, ‘without the power of knowing’). The only scientific approach to a god’s existence is to say, ‘I cannot explore that question using the scientific method with any hope of success, therefore I should not try.’ Many scientists believe in a god as an act of faith. There is no contradiction here. Science is only capable of investigating the physical universe, yet scientists are human, and two of the cornerstones of the human condition are our logic and our intuition – parallel approaches in the way we build our view of the universe. Science and religion reflect these two approaches. They can survive and flourish together.
Fossils
Applying the scientific method to an investigation of the natural world is not difficult when we are examining the present, but becomes much harder when we start to explore the past (scientists can’t record the mating calls of dinosaurs). However, that doesn’t mean it’s impossible to explore the past using science. As long as a theory is testable, it can be scientific; and a test need not be a laboratory experiment, it can also be a prediction. For example, if birds evolved from reptiles then somewhere in the rocks should be fossils showing a mixture of reptile and bird characteristics. If palaeontologists look for these, they may eventually find them. ‘Birds evolved from reptiles’ is therefore a testable theory, even though no one knows where to look or how long it may take. In fact, in this example a fossil has already been discovered. Archaeopteryx, found in a German quarry in 1861, shows just such a mixture of characters. However, the finding of fossils may rely more on luck than judgement. Most animals and plants are not fossilised when they die, they are eaten or their bodies are destroyed by scavengers or decomposition. Only unusually are some remains protected from destruction and turned to stone. Even then, most fossils will later be destroyed by erosion of the land over geological time or may lie so deeply underground that no one knows anything about them. Fossils are found only when someone interested in fossils stumbles across rocks in the process of being eroded and notices the telltale signs, or when engineers excavate mines or quarries. The chances of any fossil being discovered in the brief period when it’s visible are therefore very remote and we shall never have a complete and accurate record of all the animals and plants that lived at a particular time or in a particular place. Studying palaeontology is like trying to analyse a game of football when all you can see are the shadows, and clouds keep drifting across the sun.
