In modern philosophy, essentialism is in most cases regarded as an outdated and, in fact, incorrect philosophical trend. And one of the scientists who created such a reputation of essentialism was the famous English philosopher of Austrian origin Karl Popper. The success of his book “The Open Society and its Enemies” led to the fact that in the West essentialism began to be considered not only cognitively untenable, but also suspicious as the theoretical basis of fascism, communism and totalitarianism. In (...) the article, K. Popper’s arguments against essentialism are reviewed all over again, and it is shown that K. Popper’s criticism of essentialism as an anti-scientific and outdated doctrine is not the point of view of the philosophy as a whole, but it is just the position of empirical positivism. Essentialism deals with the reality that lies on the other side of phenomena. And this, according to K. Popper, necessarily leads to “ultimate” definitions. However, in accordance with the doctrine of falsification by K. Popper himself, every scientific conclusion within its expiration date is “ultimate”. The article shows that in reality essentialism did not only play an extraordinary role in the classical metaphysical theory of knowledge, but also continues to do so within the framework of modern ontology. Moreover, in the latter case, he does it with the help of abduction which is a specific form of logical inference generating scientific hypotheses. The existence of abduction in science, which generates new knowledge, suggests that essentialism is not something, at best, tolerable and excusable. This is the main way to development of sciences in general. In all cases, the author of the article considers only logical entities, but not legal, theological or any other. (shrink)