The Problem of Demarcation

The debate on how to distinguish between scientific knowledge and other ideas is still valid.


In the philosophy of science, the problem of demarcation refers to how to specify what are the limits between the scientific and what is not.

Despite the ancient nature of this debate and that a greater consensus has been gained regarding what the basis of the scientific method is, today there is still controversy when it comes to defining what a science is. Let’s see some of the currents behind the problem of demarcation, mentioning its most relevant authors in the field of philosophy.

What is the problem of demarcation?

Throughout history, human beings have been developing new knowledge, theories and explanations to try to describe natural processes in the best possible way. However, many of these explanations have not started from solid empirical bases and the way in which they described reality was not entirely convincing.

That is why in several historical moments the debate about what clearly delimits a science of what is not has been opened. Today, despite the fact that access to the Internet and other sources of information allows us to quickly and safely know the opinion of people specialized in a subject, the truth is that there are still enough people who follow positions and ideas that were already discarded many years, such as the belief in astrology, homeopathy or that the Earth is flat.

Knowing how to differentiate between the scientific and what appears to be is crucial in several aspects. Pseudoscientific behaviors are harmful both for those who believe them and for their environment and even for society as a whole.

The movement against vaccines, who argue that this medical technique contributes to children suffering from autism and other conditions based on a worldwide conspiracy, is the typical example of how pseudoscientific thoughts are seriously harmful to health. Another case is the denial of human origin in climate change, making those who are skeptical of this fact underestimate the harmful effects on the nature of global warming.

Classical Era

Already at the time of Ancient Greece there was interest in delimiting between reality and subjectively perceived. It differed between true knowledge, called episteme, and the opinion or beliefs of its own, doxa.

According to Plato, true knowledge could only be found in the world of ideas, a world in which knowledge was shown in the purest possible way, and without the free interpretation that human beings gave of these ideas in the real world .

Of course, at this time science was not conceived as we do now, but the debate revolved around more abstract concepts of objectivity and subjectivity.

Crisis between religion and science

Although the roots of the demarcation problem deepen in the classical era, it was in the nineteenth century that the debate took real strength. Science and religion differed more clearly than in previous centuries, and were perceived as antagonistic positions.

The scientific development, which tried to explain the natural phenomena regardless of subjective beliefs and going directly to the empirical facts, was perceived as something that declared war on religious beliefs. A clear example of this conflict can be found in the publication of The Origin of Species, by Charles Darwin, which generated a genuine controversy and dismantled, under scientific criteria, the Christian belief of Creation as a process guided voluntarily from a form of divine intelligence.

Logical positivism

At the beginning of the 20th century a movement arises that seeks to clarify the limit between science and what is not. Logical positivism addressed the problem of demarcation and proposed criteria to clearly delineate that scientific knowledge of which he pretended to appear or pseudoscientific.

This current is characterized by giving much importance to science and being contrary to metaphysics, that is, what is beyond the empirical world and, therefore, cannot be demonstrated through experience, as would be the existence of God.

The positivists considered that in order for a statement to be scientific it must have some kind of support, whether through experience or reason. The fundamental criterion is that it should be able to be verified.

For example, demonstrating that the earth is round can be verified empirically, going around the world or taking satellite photographs. In this way, you can know if this statement is true or false.

However, the positivists considered that the empirical criterion was not enough to define whether something was scientific or not. For formal sciences, which can hardly be demonstrated through experience, another demarcation criterion was necessary. According to positivism, these types of sciences were demonstrable if their statements could justify themselves, that is, they were tautological.

Karl Popper and falsificationism

Karl Popper considered that for science to advance it was necessary, instead of looking for all the cases that confirmed a theory, to look for cases that denied it. This is, in essence, his criterion of falsificationism.

Traditionally, science had been done on the basis of induction, that is, to suppose that if several cases were found that confirmed a theory, it had to be true. For example, if we go to a pond and see that all the swans there are white, we induce that the swans are always white; but … what if we see a black swan? Popper considered that this case is an example that science is something provisional and that, if something is found to deny a postulate, what is given as true would have to be rephrased.

According to the opinion of another philosopher before Popper, Emmanuel Kant, a very skeptical or dogmatic view of current knowledge should be taken, given that science implies a more or less certain knowledge until it is denied. Scientific knowledge must be able to be tested, contrasted with reality to see if it fits what the experience says.

Popper believes that it is not possible to ensure knowledge no matter how much a given event is repeated. For example, by induction, the human being knows that the sun will rise the next day by the simple fact that this has always happened. However, this is not a true guarantee that the same will really happen.

Thomas Kuhn

This philosopher considered that what Popper proposed was not sufficient reason to delimit a certain theory or knowledge as non-scientific. Kuhn believed that a good scientific theory was something very broad, precise, simple and consistent. When applied, the scientist must go beyond just rationality, and be prepared to find exceptions to his theory. Scientific knowledge, according to this author, is found in theory and rule.

In turn, Kuhn came to question the concept of scientific progress, because he believed that with the historical development of science, some scientific paradigms were replacing others, without this implying in itself an improvement over the above: It goes from one system of ideas to another, without these being comparable. However, the emphasis he placed on this relativistic idea varied throughout his career as a philosopher, and in his last years he showed a less radical intellectual stance.

Imre Lakatos and the criteria based on scientific development

Lakatos developed the scientific research programs. These programs were sets of interrelated theories in such a way that some are derived from others.

In these programs there are two parts. On the one hand there is the hard core, which is what the related theories share. On the other side are the hypotheses, which constitute a protective belt of the nucleus. These hypotheses can be modified and are the ones that explain the exceptions and changes in a scientific theory.