Knowledge can become out of date, because what we thought to know appeared not to be true. The case of Galileo that I described two weeks ago is an instance of this: the sun does not turn around the earth, as people thought in his days, but it is the other way round, as Galileo showed. So what we thought to know has never been the case. Actually, it has never been knowledge: it was false knowledge. But is it so that all supposed knowledge that later appeared to be false knowledge always has been false knowledge? Take the so-called bystander effect, the phenomenon that most persons do not help a victim in an emergency situation (for instance a drowning person), when other people are present, while they would help, if they were there alone. However, now I read in an article that it has become difficult to replicate the bystander effect in an experimental setting. Apparently people have changed – maybe because the phenomenon got much attention in the media and in publications – and the bystander effect does no longer exist: people do help now in emergency situations, even when they are in a group. What once was true has now become false and has been replaced by new knowledge.
On the face of it, it seems here that a piece of knowledge simply has become out of date and has been replaced because we know better now. However, there is an important difference with the Galileo case. There the original idea that the sun turns around the earth has always been false, but the bearers of this supposed knowledge were not acquainted with this. However, the bystander effect has not become out of date because it never has been true, for once it was. It has become superseded because reality has changed. This is typical for the social sciences: people get knowledge of certain social facts, which are true at the moment they hear about it. However, for one reason or another, people are not satisfied with the facts and they change them. Then old knowledge becomes the foundation of new knowledge instead of being falsified. By the way, it can also happen that what once was false is made true: a teacher undeservedly thinks that some students in his class are better than other students and just because of his – often unconscious – behaviour the allegedly better students also become better, as psychological research has shown: false knowledge has turned into true knowledge. And in fact, the reversal of the bystander effect is also a case in point: the false knowledge that people tend to help in emergency situations even in case others are present, has become true when people became conscious of their behaviour.This interpretative effect (called “double hermeneutics”) does not exist in the natural sciences. However, also there it can happen that knowledge becomes outdated and has to be replaced by new knowledge without being falsified. Old medical knowledge is often replaced by new knowledge, not because it has been falsified, but because now we know better. But in a certain sense the medical science is a social science. The latter is not the case for biology and for the biological world, for instance. Nature is in continuous development and what once was true about it, is not valid anymore many years or ages later. Even if our knowledge isn’t true, it needn’t be false. There are many ways that it can appear to be wrong.