A Christmas Tale…
Last Christmas, my six year old son came up with a brilliant plan.
If you can’t buy something in the shops… ask Father Christmas for it!
Some time ago, one of the major supermarkets made chocolate orange spread – spreadable chocolate orange! It became an instant favourite and we stockpiled a few jars.
Excited to be allowed to spread it on his toast one morning, our son was a little too hasty and dropped the last jar, cracking the bottle, spreading sticky chocolate everywhere. Trusting Mummy and Daddy completely, he was reassured that we would get a new jar and settled on something else for breakfast.
Alas, the supermarket had stopped producing it and we could not find anything like it anywhere else we looked. Over the next few weeks it became a minor obsession – a few other shops taunted us by making space for it on their shelves or listing it on their websites but the shelves were always empty and the websites always said that it was temporarily out of stock.
We told our son that the shops would bring it back soon and secretly hoped that his taste would fade away and be forgotten.
Then came the day when he wrote his letter to Father Christmas. Top of the list, ‘Chocolate Orange Spread’.
When we asked about it, his logic was impeccable. Father Christmas does not use local shops, supermarkets or the internet. He has secret factories of magic elves at the North Pole who can make anything whenever he wants!
Let’s think about that logic for a moment…
Traditional, Inductive Science
Francis Bacon (1561–1626) was the first person to set out a systematic procedure that scientists should use to develop accurate theories of how the world works.
In his opinion, scientists should start by making as many observations as possible and while making these observations, they should simply record what they see without imposing any of our own ideas or giving any opinions on what they record. In time, when enough observations have emerged, patterns should emerge in the observations and from these it should be able to infer – i.e. make an educated guess about – the general laws that are at work. Of course, it is always possible that more than one possible interpretation of the patterns might be possible, so at this point scientists might need to do an experiment to test which interpretation is correct. To do this, they should make a prediction based on one of the interpretations (a hypothesis) and if the evidence supports the hypothesis, then they can infer that the interpretation is correct and ignore others. At this point, they have developed a theory and it should stand as a tried and tested fact about the way the world works.
This is now known as the inductive method of science 1.
This is what my son was trying to do with Father Christmas. In the past, whenever he had asked Father Christmas for something, it had appeared, so he could presume that Father Christmas could provide anything.
The problem is that this inductive method is open to errors at several points. Firstly, it is almost impossible to make objective observations because our existing beliefs will affect what we choose to observe. Second, it is very hard not to allow our biases to impact on the generalisations we make. Third, no matter how much evidence we gather to support a hypothesis, it is always possible that some further evidence will disprove it and consequently disprove the theory.
In this way, my son was similar to the superstitious mystic who finds that one dream that they have had comes true, so believes that all dreams tell the future. Or to Sigmund Freud who presumed that his observations of his first case studies were objective when they were actually heavily influenced by his assumption that everything was powered by the libido, built a theory that was almost impossible to test, and then always looked for evidence to support his theory in any later case studies. For anyone studying cognition and development, it is also the flaw that Jean Piaget made when he created his ingenious experiments to support his theory, but did not look for alternative explanations for the results.
Curiously, it is also the method that Sherlock Holmes used.
The modern, hypothetico-deductive Science
Until the middle of the twentieth century, everyone seems to have been happy with the idea that scientists were more objective than everyone else and once a theory had been tested then it was fact. The problem was that flaws were found in many of the great theories at the beginning of the twentieth century. Even though many of them had centuries of evidence accumulated to support them, it could no longer be assumed that the theories were correct and if the theories were flawed, then perhaps the systematic inductive approach that lead to their creation might also be flawed.
In 1934, Popper’s ‘Logic of Scientific Discovery’ provided an entirely new view of how science works.
In this view, it was wrong to assume that scientific theories could ever be true facts. Instead, theories should be viewed as the best available statement of how scientists think the world works. Even before any evidence has been gathered, scientists should state a theory, if only because the theory makes clear what assumptions they are making before they start. From the Theory, the scientists should be able to make precise predictions about what will happen in specific situations in the world. Most importantly, Popper did not think that evidence should be used to support these hypotheses; instead, scientists should try to find evidence to disprove them. The logic is that if you try to support a hypothesis, you are likely to ignore evidence that does not support it or you might jump to conclusions then find that others later disprove it. On the other hand, if you set out to disprove a hypothesis and can’t, then you are forced to assume that it is likely to be true even though you have to remain a little cautious 2. Over time, theories that are disproved lose value, while those that are hard to disprove emerge and are refined.
This approach to conducting research is known as the hypothetico-deductive method 3.
You can see this process in action if you study Memory. At one point, people thought that memory was one big store where everything you knew was held. Once research on memory started, this model was fairly easily disproved and the Multi-Store Model emerged that recognized there were three stores – Sensory Register, Short Term Memory and Long Term Memory. Efforts to test this theory showed that it was also flawed, and models that recognised different types of long term memory and that it was better to perceive short term memory as a Working Memory processing system rather than a store emerged. Even today, considerable work is still going on to test the Working Memory Model and find areas where it could be refined.
You may also recognise the hypothetic-deductive method when you use inferential statistics. The underlying logic of all the statistical tests you use is that there is no effect of the independent variable in a test of difference or that there is no correlation between variables in a test of relationship, then try to disprove it. If the evidence shows that any observed effect is unlikely to have happened by chance, then the null has been disproved and the alternative hypothesis has to be accepted.
If my son were a modern scientist who wanted to test whether Father Christmas existed, they could start from the assumption that Father Christmas can’t deliver the chocolate orange spread and try to disprove that. Then, even if evidence suggested that he did exist, they would have to hold in mind that his existence is only the best available theory and further evidence might still disprove them. Alternatively, they might seek evidence that Father Christmas did not exist. Then they would be forced to hold the theory that Father Christmas does exist until they were able to find any evidence to the contrary.
In the Classroom
So how could you use this in the classroom?
First, of course, you could direct any students who are interested in the difference between inductive and deductive science to read this blog.
Second, you might create a Christmas challenge for them. Tell them my son’s story, then ask them to design a study to test whether Father Christmas exists. Once they have created their own ideas, you could explain the difference between inductive and deductive science, and ask them to identify which one they have used. To end the lesson, you could ask them to discuss which is better.
I find this sort of abstract research task makes a great “Friday Afternoon” task. The students can learn to apply research methods in a topic that is completely detached from anything they might cover on the course and reflect on how the principles can be applied more generally.
A Christmas Tale revisited…
In case any of you are still wondering, Father Christmas and his elves did deliver a jar of the chocolate orange spread on Christmas morning.
Dr George Smith teaches at Clayesmore School in Dorset. After his degree, he combined his love of technology and language by conducting research into computer-mediated communication. He moved into teaching when he discovered that he enjoyed the daily excitement of dealing with the challenging questions asked by A Level students more than sitting in a lab by himself writing software.
- Lewens, T., 2015, The Meaning of Science, Pelican
- Clearly written, but probably best as extension reading for A Level students who are thinking about a course that involves some philosophy.
- Magee, B., 1998, The Story of Philosophy, Dorling Kindersley
- Very clearly written and as attractively laid out as any other DK book. Covers a lot more philosophy than is needed in the Psychology A Level, but you can easily dip in and out.
- Okasha, S., 2016, The Philosophy of Science: A Very Short Introduction, Oxford University Press
- In Our Time, 2012, The Scientific Method, http://www.bbc.co.uk/programmes/b01b1ljm
- Before I teach the scientific approach, I always listen to this on my drive to work – it seems to clear up all the little errors in my memory of the two approaches to science that re-appear from year to year.
There are several other relevant In Our Time episodes, but none that covers everything we need to teach so succinctly. You may find these interesting:
In Our Time, 2009, Baconian Science, http://www.bbc.co.uk/programmes/b00jdb6c
In Our Time, 2007, Popper, http://www.bbc.co.uk/programmes/b00773y4
In Our Time, 1998, Science in the 20th Century, http://www.bbc.co.uk/programmes/p005457h
1. It is called the inductive method in science because it is similar to a philosophical method called inductive reasoning that bases conclusions that are probably true on specific statements that are certain to be true, but does not absolutely guarantee that the conclusion is true
– All my teachers believe in Father Christmas.
– It is likely that any other teacher I meet will believe in Father Christmas.
3. It is called the hypothetico-deductive method in science because it is similar to a philosophical method called deductive reasoning that is concerned with working from statements to a logically certain conclusion.
– All elves are magical.
– Father Christmas is an elf.
– Father Christmas is magical.