How do scientists do science?

Rules of the game

Scientists try to figure out the rules behind natural phenomena. We simulated this in our "dice experiment" during the lesson. The interesting thing about this experiment was that we came up with different rules to explain the same phenomenon. This often happens in science.

Of course doing real science is more complicated and involves laboratory experiments, measuring devices and teamwork with other scientists. Science is very much a social endeavour.

Bit like trying to figure out the rules for the “dice experiment”, some philosophers have tried to figure out the rules for doing science. They have asked how do scientists think when they do science?

Inductive thinking

The first answer to this question was that scientists think inductively. They observe phenomena and produce generalisations regarding how things seem to work. These generalisations could be called laws of nature.

This theory of science has some problems however. Imagine what you would say if your biology teacher set you this homework “Go to the Khao Sok national park and observe!” Your first question would probably be, “What are we supposed to observe?” It seems therefore that there is no pure observation, but we always think of our observations through some kind of theory. The theory precedes observation.

If you look at this picture you may observe and interpret it according to female face theory or saxophone theory. The mind is actively interprets all our sense perceptions.

There are other problems too. No matter how many observations we have of a particular phenomenon, we can never draw certain conclusions. Inductive thinking never gives us certainty. Even if all swans we have seen were white, it is possible there are black swans, and indeed there are, in Australia!

Hypothetico-deductive thinking

So, if science is not based on inductive thinking what is it based on? Karl Popper was an Austrian philosopher tried to come up with an answer to this question. You know he was a German speaker because his answer was: hypothetico-deductive thinking. (The Germans are famous for their long words).

Popper thinks that scientist first create a hypothesis (a guess what the rules behind observations may be), then conduct empirical tests to see if the hypothesis can be falsified (proved wrong). If the hypothesis cannot be falsified, i.e. results of the test are as the hypothesis predicts them to be, we tentatively accept the hypothesis as a new theory.

According to Popper scientists should try to falsify existing scientific theories as quickly as possible and replace them with theories that explain the phenomena better. This is how science makes progress.

So, why is this called hypothetico-deductive method? Because firstly you create hypothesis (a guess) and then you test and use deductive logic to reach a conclusion. If the did not prove the hypothesis wrong, we accept that hypothesis. Accepting hypothesis because it is not wrong and an example of deductive thinking.

Popper's idea is interesting because we can use it tell apart theories that are truly scientific from those that only look scientific. Any hypothesis or theory that we cannot be proved wrong is not really scientific.

• Example 1. A statement ‘metals expand when heated’ is scientific, because we can imagine a situation in which this statement would be falsified (i.e. heating a metal and finding out that it does note expand).

• Example 2. A statement ‘human behaviour is caused by unconscious desires’ is unscientific because we cannot imagine a behaviour that would falsify this statement. (This is why Freud’s theories are not really scientific).

Paradigm shifts

When many scientists in a particular field think alike about some important issues, we say that there is a paradigm. Sometimes a brilliant scientist who is an original thinker comes along and proposes a theory that completely revolutionises the way we think.

For example in physics Newton was such a scientist. So wonderful was his theory that for a long time people thought we knew pretty much everything about physics and there was nothing to discover (Newton suggested that mass is constant). That is until Einstein came along and completely revolutionarised our understanding of physics (Einstein suggested that the speed of light is constant). His theory was better than Newton's. It explained more and it matched better with empirical observations.

When scientific revolutions like this happen we call them paradigm shifts. They do not happen very often but when they do science is taking huge leaps forward. There are some philosophers who are trying to figure out how and why these paradigm shifts happen. The first philosopher to introduce the idea of paradigm shifts was Thomas Kuhn. According to him these revolutions are so profound that one paradigm is incommensurable (incompatible) with one another. This means that it is impossible to marry Newton’s and Einstein’s theories, they just do not fit.

There are other interesting thinkers who explain how scientists think and how science progresses but this is already plenty. The main lesson to learn is that scientist do not prove their theories but disprove them and replace them with better one, and that science does not progress steadily but sometimes there are revolutions.