The core of the theory of knowledge has always been the problem of truth and its criteria. All philosophical schools and schools tried to formulate their understanding of these issues. Aristotle was the thinker who gave the world a definition that has become a classic: truth is the means by which we understand whether our knowledge complies with the actual state of things. We can say that this definition satisfied the philosophers of all, even warring camps - metaphysicians, and dialecticians, and materialists, and idealists. It was recognized by most epistemological theorists, from Thomas Aquinas to Karl Marx. The difference was only in what they considered reality, and what mechanism of conformity with reality was recognized.
The truth and its criteria in the traditional sense can be analyzed on the basis of the following components. Firstly, the reality, which corresponds to the correct knowledge, is recognized as objective and existing regardless of our consciousness, and the essence of the knowable is comprehended through the phenomenon. Secondly, the truth is the result of cognition and is associated with the activity of a person, with his practice, and how much we were able to understand the essence, studying the phenomenon, sooner or later it turns out in practice. From this point of view, the truth should adequately reflect the object of knowledge in the form in which it exists independently of the subject. But this connection is accessible only to logic, and therefore traditionally the logical proof is the criterion of knowledge.
On the other hand, Kant also put forward the idea that truth and its criteria cannot be determined in the framework of the development of theoretical science, since this science itself cannot provide complete knowledge even about nature due to the limitations of the human mind. Moreover, Kant believes that a person lives in two worlds at the same time - natural and cultural. The natural world obeys the laws of causality and necessity, it is cognizable by theoretical reason, but this mind is powerless to know the essence of phenomena and only moves from one system of errors to another. And the world of culture is a world of freedom, cognizable by practical reason, that is, a will that obeys the laws of morality, and does not miss, but acts almost unmistakably. Therefore, for Kant, the main criterion becomes a moral requirement.
The problem of the criterion of truth is not alien to modern understanding, only it has its own specifics. From the point of view of materialism and positivism, such a criterion can be determined thanks to the dialectical connection of such concepts as objective, absolute, relative, and concrete truth. The concept of objectivity, applied to the content of a person’s knowledge of reality, means that we are talking about the independence of this content both from a person and from society. In this regard, any objective truth can be called absolute, but only to a certain extent. The enrichment and development of knowledge leads to a change and expansion of the content of our ideas about the world, and therefore objective truth is also relative. The term "concreteness" allows you to define the boundaries of absoluteness and relativity, and the criterion of correctness is practice.
It can be said that truth and its criteria have become the section that has generally divided the philosophers of our time into supporters of the post-positivist Karl Popper and the founder of philosophical hermeneutics Hans Georg Gadamer. Popper considered most of the concepts of philosophy, ethics, aesthetics and theology to be emotional categories that justify certain ideologies. Therefore, the modern classic considered the main tool of analysis to be rationalism, using which philosophy can draw a “demarcation line” between science and pseudoscience, truth and error. Indeed, there are no absolutely correct scientific theories, but there are conditional hypotheses that are true for their level of science, but they become such only when they are subjected to critical verification (falsification). Thus, from the point of view of Popper, the main criterion for the difference between science and metaphysics is the critical principle of falsification.
Truth and its criteria are the main theme of the sensational work of Hans-Georg Gadamer "Truth and Method." In it, the philosopher does not show the connection of these two categories, but their complete incompatibility. The scientific way of knowing, known as the method, is neither universal nor unique. Scientific and theoretical development of the world is applicable neither to language, nor to aesthetics, nor to history, it only narrows and impoverishes the experience of truth, accessible not through study, but through understanding. The latter is only available when the "horizon of understanding" of the author and the interpreter merges, fuses, and a dialogue takes place between them. The existence of such a dialogue and the search for a common language between different cultural traditions is a criterion for the truth of humanitarian knowledge.