Despite the importance of the variational principles of physics, there have been relatively few attempts to consider them for a realistic framework. In addition to the old teleological question, this paper continues the recent discussion regarding the modal involvement of the principle of least action and its relations with the Humean view of the laws of nature. The reality of possible paths in the principle of least action is examined from the perspectives of the contemporary metaphysics of modality and Leibniz's (...) concept of essences or possibles striving for existence. I elaborate a modal interpretation of the principle of least action that replaces a classical representation of a system's motion along a single history in the actual modality by simultaneous motions along an infinite set of all possible histories in the possible modality. This model is based on an intuition that deep ontological connections exist between the possible paths in the principle of least action and possible quantum histories in the Feynman path integral. I interpret the action as a physical measure of the essence of every possible history. Therefore only one actual history has the highest degree of the essence and minimal action. To address the issue of necessity, I assume that the principle of least action has a general physical necessity and lies between the laws of motion with a limited physical necessity and certain laws with a metaphysical necessity. (shrink)

Twenty extremal principles of the natural sciences are reformulated to the general ontological scheme. The hypothesis is substantiated that the unique role of the principle of least action is based on its probabilistic interpretation. It is shown how most of the variational principles can be reduced to the principle of maximal probability, which is based on a realistic interpretation of Feynman’s path integral method.

The framework of a simple opposition realism – anti-realism is not enough to analyze the views on the reality of unobservable objects of quantum theory. First, it is necessary to distinguish between realism in relation to the theory and realism in relation to the theory’s objects. Secondly, realism in relation to classical objects can be combined, both with realism and with anti-realism in relation to quantum objects. Third, the concept of “existence” and “to exist objectively” can have different meanings. To (...) take into account these factors, the article describes three approaches: classical realism, quantum anti-realism, and quantum realism. I show that the debate around quantum reality has intensified in recent decades due to a series of new quantum experiments. The current stage of the debate is caused by the second quantum revolution relating to the transfer and processing of quantum information. Classical realism and old versions of quantum anti-realism have become insufficiently effective to explain the results of a series of experiments. Proponents of quantum realism, in turn, refer to the possibility of using the wave function to manipulate quantum objects before their measurement. In conclusion, I assume that not only theoretical discussions but also experiments and new technologies can have a major impact on the seemingly purely philosophical debate about reality. (shrink)

Despite the notions of possible worlds and substances are very important subjects of contemporary metaphysics, there are relatively few attempts to combine these in a united framework. This paper considers the metaphysical model of the origins and the evolution of possible worlds that occurs from an interaction between substances. I involve Leibniz’s doctrine of the striving possibles that every possibility of substance has its own essence and tendency towards existence. It is supposed that the activities of substances are constantly aimed (...) at using this tendency in all possible ways. Only the consistent and stable interactions between the substances give birth to stable objects in one of many worlds. Thus activity of substances changes from the possible modality of being to the actual modality of being in form of existence of the worlds. I divide substance’s possibility into two aspects—dynamic (possible or virtual history) and static (possible or potential mutual state). Thanks to the summation of virtual histories, in the possible modality of being, the maximal number of virtual histories is combined into the actual history in the actual modality. (shrink)

The focus of the paper is a discussion around one of the versions of scientific realism – ontic structural realism, which has gained popularity due to the development of quantum field theory. According to OSR, individual objects do not exist as ontological primitives. The ontology of objects and their properties is replaced by the ontology of structures and relations. The paper discusses the arguments of the proponents of OSR, describing it as the only way to preserve scientific realism in general (...) relativity and in quantum physics, which are reduced to mathematical structures with different symmetries. Five possible variants of the ontological relationship between structures and objects are analyzed in detail. Particular attention is paid to the eliminative and non-eliminative versions of OSR. If the former in principle excludes any existence of objects, then in the latter, objects receive their secondary existence due to relations, and their identity is reduced to nodes in the structures of relations. The main objections to OSR and the answers of its proponents are analyzed. It is shown that references to quantum physics are both its strengths and weaknesses of OSR, since they often superficially refer to the formalism of the theory, not accepting one or another of its interpretation. The paper argues the thesis that the extreme eliminative OSR, despite all its advantages, has several serious limitations. The best way out of the situation may be the development of the non-eliminative versions of OSR. In conclusion, it provides a critical analysis of one of these versions – moderate OSR of M. Esfeld and V. Lam, who believe that structures should have causal properties, something resembling a disposition. (shrink)

This paper continues the analysis of the advantages and disadvantages of ontic structural realism, which begun in the first part of the paper. Non-eliminative versions of this approach are considered, which try to find a compromise between the ontology of structures and the ontology of objects. It is shown that the semirealism of A. Chakravartti and the constructive structural realism of T. Cao have a number of limitations caused by the authors’ desire to strictly distinguish between the nature of the (...) existence of objects and structures. Then the version of the relationship between structures and entities is presented. Firstly, two concepts are divided according to their content: “object” and “entity”. Second, to solve the problem of causality, I suggest that the nature of entities and structures lie in their ability to act. It is this ability that I propose to use instead of the popular concepts of “causal powers”, “causal properties” or “dispositions”. Third, instead of a rigid alternative to ontological primitives – either essence, or causal relations, or structures – the concept of ontological pluralism and inherited existence is proposed. There each entity is represented as a derivative of another structure and, in turn, creates other entities and structures. Thus, both structures and entities at each level of the complexity hierarchy partially inherit the ability to act and a certain degree of existence from the structures and entities of the previous levels. Finally, I am trying to clarify the modal aspects of the ontic structural realism. Following the popular interpretations of quantum theory, the ability to act, and hence the existence of structures and entities, are considered separately in two worlds – potential and actual ones. The potential world is associated with a set of possible objects and structures of quantum theory, and the actual world is associated with a set of real (observable) objects and structures of classical physical theories. The transition from the potential to the actual world is proposed to be considered as a primitive metaphysical event. The proposed concept partially overcomes the objections to ontic structural realism, thereby strengthening its position in the discussion about the reality of quantum objects. (shrink)