What is science? What knowledge is considered to be real scientific knowledge, and which knowledge does not fit into the scientific paradigm? Is it possible to consider the sciences astrology, theology, psychoanalysis?

Pseudoscience or pseudoscience is often called statements, knowledge, beliefs and practices that pretend to be scientific, but in fact they are not, because they are not obtained using the scientific method . However, there is “borderline” knowledge that either 1) is obtained by the scientific method, but is considered pseudoscience; 2) obtained as a result of reasoning in the absence of observable and measurable observations (that is, by an unscientific method), but at the same time they proved their scientific value.

How to distinguish between these two classes of knowledge?
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The philosopher Karl Popper, a mathematician and physicist by education, investigated this topic most fully in his works. The topic of science and pseudoscience is devoted to his books The Logic of Scientific Research (1935), Assumptions and Denials: the Growth of Scientific Knowledge (1963) and Objective Knowledge: An Evolutionary Approach (1972).

The concept of growth of scientific knowledge, Karl Popper has been engaged since the 20s. From the middle of the last century to the present, he is considered the most influential thinker who formulated the most coherent and convincing concept of the growth of scientific knowledge and the logical theory of the scientific method.

Popper's immediate goal was to build a logical theory of the scientific method, by which he means the empirical method. The logic of Popper's science is fundamentally different from the psychological, empirical description of scientific activity, and the apparatus of mathematical logic is an important means of its construction.

From the very beginning, Karl Popper considered the main task to clearly formulate the differences between science and pseudoscience. As a criterion, Popper proposed the principle of falsifiability, that is, the fundamental refutability of any knowledge that claims to be scientific.

This principle of Popper's philosophy was significantly different from the dominant concept of logical empiricism or neopositivism at that time. Proponents of this concept believed that the principle of verification and the confirmation of theory were inherent in scientific knowledge in the first place.

The principle of falsifiability

According to its logical content, the concept of falsification is very simple, even trivial. According to the canons of traditional logic, we know that from the conditional statement

if a, then b

it follows that falsity a . follows from falsity b with logical necessity.

The problem is that in the case of truth b, we can not say anything about the truth or falsity of a .

This simple logical rule Karl Popper made the basic principle of the assessment of scientific knowledge, the main methodological rule for distinguishing this science from pseudoscience. According to the definition of the principle of falsifiability, only those theories can be considered scientific, which in principle can be refuted, that is, which are able to prove their falsity.

While the consequences of a true statement can only be true statements, among the consequences of a false statement can be both true and false. Every scientific theory is a conjecture that will be refuted sooner or later. Therefore, each theory, strictly speaking, is false . Thus, among the consequences of any scientific theory there will be both true and false statements.

All the many consequences of the theory Popper calls its logical content. The true consequences of the theory form its true content; the rest will be false content. Comparing the two theories, we may find that the true content of one is greater than the true content of another theory, or the false content of one is less than the false content of another. For example, if an experiment shows that the prediction of one theory is true where the prediction of another theory is false, then this means that the first theory has true content where the second theory has false content. If at the same time the false content of the first theory does not exceed the false content of the second, then the first theory is more plausible than the second. The theory that gives a complete and comprehensive knowledge of the world will be as plausible as possible.

Popper himself admitted some relativity of the falsification principle, because in such a global interpretation the principle of falsification cannot be falsified.

Nevertheless, the most basic principle is considered the most concise and clear definition for the demarcation of science and pseudoscience.

In fact, Popper's philosophy opposed the principles of logical empiricism, although supporters of both concepts are undoubtedly on the same side in the war against pseudoscience. But even Popper himself later repeatedly repeated that it was he who “killed logical positivism.”

The scientific meaning of the concept of "truth"

In his early works, Karl Popper explained why the logic of scientific research has no place for the concept of "truth" , which is unclear and metaphysical. In the center of attention, he put the analysis of the logical structure of the critical installation - a critical method of scientific knowledge, the so-called fallibilism, that is, the theory of the error of human knowledge. The place of the metaphysical "truth" is taken by the theory of the credibility of scientific theories. So, in the book "The Logic of Scientific Research" Karl Popper does not use the concept of "truth" at all. But in later works, he admitted that the methodology of science still has a place for the concept of “truth” as the theory corresponds to the facts.

In the traditional concept, which comes from ancient philosophy, truth is in principle unattainable because of its conjectural and, therefore, ultimately false character. Moreover, even if we accidentally stumble upon it, Popper says, we will never know about it.

Popper also spoke against such an extreme in understanding the nature of the scientific method as apriorism, when scientific theories are considered only as a tool for predictions and therefore allegedly do not have a cognitive value in themselves.

According to the theory of truth and believability, the development of knowledge is not a transition from one true knowledge to another, but a transition from one problem to another, deeper problem.

The basic logical and methodological rule for Popper is:

"We do not know - we can only assume"

In other words, the development of scientific knowledge is based on the mechanism of trial and error - assumptions (guesses) and refutations.

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After the peak of popularity in the 60s-70s, Popper's ideas somewhat lost their influence, and the scientist himself retired. Subsequently, a number of philosophers showed the incorrect determination of the plausibility of Popper, especially in the case of comparing the plausibility of two false theories. Nevertheless, the notion of plausibility still continues to attract the attention of philosophers and logicians, and, as we have already noted, is the most concise and clear definition for the demarcation of science and pseudoscience.