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

Despite the age of this debate and the fact that a greater consensus has been gained as to what the basis of the scientific method is, there is still controversy today as to what constitutes a science. Let us look at some of the currents behind the problem of demarcation, mentioning its most relevant authors in the field of philosophy.

What is the problem with 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 been based on solid empirical foundations and the way in which they described reality was not entirely convincing.

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

Knowing how to differentiate between what is scientific and what appears to be scientific is crucial in several respects. Pseudoscientific behaviour is harmful both to those who believe it and to their environment and even to society as a whole .

The anti-vaccine movement, which argues that this medical technique contributes to children suffering from autism and other conditions based on a global conspiracy, is a typical example of how pseudo-scientific thinking is seriously harmful to health. Another case is the denial of the human origin of climate change, causing those who are skeptical of this fact to underestimate the harmful effects of global warming on nature.

The debate on what science is throughout history

The following are some of the historical trends that have addressed the debate on what the demarcation criterion should be.

1. Classic Period

Already in Ancient Greek times there was an interest in demarcating between reality and the subjectively perceived. A distinction was made between true knowledge, called episteme, and one’s own opinion or beliefs, 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 form possible, and without the free interpretation that we human beings gave of these ideas in the real world.

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

2. Crisis between religion and science

Although the roots of the problem of demarcation go back to the classical period, it was in the 19th century that the debate took on real strength . Science and religion differed more clearly than in previous centuries, and were perceived as antagonistic positions.

Scientific development, which tried to explain natural phenomena by dispensing with 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 real controversy and dismantled, under scientific criteria, the Christian belief in Creation as a process voluntarily guided from a form of divine intelligence.

3. Logical positivism

At the beginning of the 20th century, a movement emerged that sought to clarify the boundary between science and what it is not. Logical positivism addressed the problem of demarcation and proposed criteria to clearly delimit that knowledge which was scientific from that which pretended to be scientific or pseudo-scientific.

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

Among the most outstanding positivists are Auguste Comte and Ernst Mach. These authors considered that a society will always achieve progress when science is its fundamental pillar. This would mark the difference between previous periods, characterized by metaphysical and religious beliefs.

The positivists considered that for a statement to be scientific it must have some kind of support, either through experience or reason . The fundamental criterion is that it should be verifiable.

For example, proving that the earth is round can be verified empirically by going around the world or taking satellite pictures. In this way, it is possible to know whether this statement is true or false.

However, the positivists considered that the empirical criterion was not sufficient to delimit whether something was scientific or not. For the formal sciences, which are difficult to demonstrate through experience, another demarcation criterion was necessary. According to positivism, this type of science was demonstrable if its statements could be justified by themselves , that is, if they were tautological.

4. Karl Popper and Falsehoodism

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 falsehood.

Traditionally, science had been done on the basis of induction, that is, assuming 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 of the fact that science is something provisional and that, in case something is found that denies a postulate, what is given as true would have to be reformulated .

According to the opinion of another pre-Popper philosopher, Emmanuel Kant, one should take a view that is neither very sceptical nor dogmatic of current knowledge, since science presupposes more or less secure knowledge until it is denied. Scientific knowledge must be able to be tested , contrasted with reality to see if it fits with what experience says.

Scientific development, which tried to explain natural phenomena by dispensing with 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 real controversy and dismantled, under scientific criteria, the Christian belief in Creation as a process voluntarily guided from a form of divine intelligence.

3.
Logical positivism

At the beginning of the 20th century, a movement emerged that sought to clarify the boundary between science and what it is not.
Logical positivism addressed the problem of demarcation and proposed criteria to clearly delimit that knowledge which was scientific from that which pretended to be scientific or pseudo-scientific.

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

Among the most outstanding positivists are Auguste Comte and Ernst Mach. These authors considered that a society will always achieve progress when science is its fundamental pillar. This would mark the difference between previous periods, characterized by metaphysical and religious beliefs.

The positivists considered that for a statement to be scientific it must have some kind of support, either through experience or reason .
The fundamental criterion is that it should be verifiable.

For example, proving that the earth is round can be verified empirically by going around the world or taking satellite pictures.
In this way, it is possible to know whether this statement is true or false.

However, the positivists considered that the empirical criterion was not sufficient to delimit whether something was scientific or not. For the formal sciences, which are difficult to demonstrate through experience, another demarcation criterion was necessary. According to positivism, this type of science was demonstrable if its statements could be justified by themselves , that is, if they were tautological.

4. Karl Popper and Falsehoodism

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 falsehood.

Traditionally, science had been done on the basis of induction, that is, assuming 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 of the fact that science is something provisional and that, in case something is found that denies a postulate, what is given as true would have to be reformulated .

According to the opinion of another pre-Popper philosopher, Emmanuel Kant, one should take a view that is neither very sceptical nor dogmatic of current knowledge, since science presupposes more or less secure knowledge until it is denied. Scientific knowledge must be able to be tested , contrasted with reality to see if it fits with what experience says.