The Scandal of Induction


The movement from particular observations – if I drop this pencil it will fall – to general laws – if I drop any pencil it will fall– is called induction and it is one of the basic elements of science.


Imagine you’re an alien and want to find out what human beings have inside their heads. You would not want to do experiments on every human being to find out if they have a brain inside their skull: smashing open everyone to check for the presence of a brain would take a long time and cause a lot of mess. So you would smash open only a few hundred thousand heads and, on the basis that all the rest of the human beings are pretty much like the ones that you have smashed open so far, you would probably conclude, not unreasonably, that all human beings have a brain inside their head.


However, the philosopher Hume pointed out a critical problem with this method. Taking the example of the sun rising on a daily basis we assume that it will rise the next day simply because it has always done so before. But there is really no logical reason for it to be this way. Just because it’s always happened this way, that doesn’t mean that it can’t change. To carry on with the destructive theme, imagine that a huge blazing meteor were to collide with the Earth tonight and obliterate the planet. If that were to happen, there would be no sunrise tomorrow.


To use a more down to earth example: before the 16th Century everyone in Europe thought that the universal law ‘All swans are white’ was true because every swan that they had ever seen was white. However, when travelers came back from Australia and New Zealand they reported having seen black swans thus providing a nice real life example of how, just because every swan you’ve ever seen is white, it doesn’t mean that somewhere there isn’t a black swan lurking about waiting to prove you wrong.


Hume’s criticism of induction is often simply known as “Hume’s problem” or the scandal of induction and it poses a real problem for science as all of the universal laws generated by science rely on induction.



The Solution?


Karl Popper offered a potential solution to this problem by thinking about the way we do science in a new light. Essentially, Popper turned science on it’s head by claiming that we are looking at science in the wrong way. Instead of looking at science to provide us with theories that are definitely true Popper said that we should be looking at science to provide us with theories that we have failed to prove false for a very long time. This approach to science is called Falsificationism.


Fundamentally, Popper accepts that science can never provide us with complete 100% certainty but, he claims, this is not really a problem because that is not actually science’s job. The job of science is simply to provide us with a theory that is likely to be true based on the fact that we haven’t yet managed to prove it wrong. One unfortunate consequence of this, however, is that you can only ever be certain of the things that you have proved wrong. We know, for example, that the world definitely is not flat. The problem with this fact is that, although certain, it is not actually that useful to know that something is definitely false.