Physicists usually admit a rather naive concept of physical reality: it is the object they are investigating using experiments understood as actions in the real world.in theoretical physics, the object of investigation is not the real world itself but its mathematical description which is considered as describing physical reality as exactly as possible.i present arguments from philosophy of science and from recent work in the theory of gravitational physics which indicate a possibility to defend also antirealistic views, and clarify in which sense both standpoints can be viable.
Physicists usually admit a rather naive concept of physical reality: it is the object they are investigating using experiments understood as actions in the real world.in theoretical physics, the object of investigation is not the real world itself but its mathematical description which is considered as describing physical reality as exactly as possible.i present arguments from philosophy of science and from recent work in the theory of gravitational physics which indicate a possibility to defend also antirealistic views, and clarify in which sense both standpoints can be viable.
Both science and philosophy have been characterized as seeking to understand the nature of reality. They are sometimes even pitted against each other, suggesting that the success of science undermines the relevance of philosophy. But attending to the sort of understanding or explanation being sought offers a different picture: contemporary physics as practiced sometimes fails to provide a clear physical account of the world. This lies at the root of the dissatisfaction with standard quantum theory expressed by Einstein, Schrödinger, and John Bell. As an example, close consideration of Schrödinger's famous cat example suggests that physicists often have missed his point. What a philosophical disposition can contribute is not alternative physics, but rather the sort of careful attention to argument needed to extract a physical picture from a mathematical formalism.
I am very grateful to the Master and Fellows of Trinity College for inviting me to give the Tarner Lectures. What I want to do in this book, stated boldly and baldly, is to consider the relevance of developments in modern theoretical physics to metaphysical questions about the ultimate nature of reality. By metaphysical questions I mean the very general sorts of questions that arise out of a critical examination of the principles, concepts and fundamental presuppositions that lie behind modern physics. How should we interpret the claims that physicists seem to be making about the world? Are they intended to be understood as literally true, for example, and exactly what are those claims, given that the pages of theoretical physics monographs are largely filled with abstract mathematical formalism? In the first chapter, I shall be looking at a range of philosophical points of view in the framework of which such questions can be addressed, and attempt the difficult task of adjudicating between the different approaches. At the end of the day I shall be arguing for a pretty straightforward metaphysical realism, that the external world exists independently of our knowledge of it. In the second chapter I shall look at arguments from various branches of modern physics that are sometimes claimed to bring in an essential role for subjectivity in physics, bringing the observer into a central role, creating his own reality.
Despite its power as the conceptual basis for a huge range of physical phenomena in atomic and subatomic physics, quantum mechanics still suffers from a lack of clarity regarding the physical meaning of its fundamental theoretical concepts, such as those of quantum state and of quantum theoretical quantities or variables , dealt with by the known mathematical-theoretical rules. These concepts have generally been considered as not giving a direct description of physical systems, for they do not correspond to what is usually understood by `physical states' or `physical properties', notably characterized by definite numerical values such as those obtained from measurement. The situation has been tentatively expressed in terms of various `interpretations', conceived not only with regard to the physical meanings of mathematical quantities, but also in connection with philosophical statements about `physical reality'. The question of whether or not quantum theoretical quantities describe definite physical systems existing in nature has therefore generally been considered as beyond the possibilities of physics, because of the definitions that are commonly taken for `physical state' and `physical quantity'. We sketch the main ideas on this problem and propose a possible way out of the puzzle, in terms of an extension of the meaning given to the concepts of the physical state and physical quantity of a system, which would allow one, without any theoretical change in quantum mechanics, to speak consistently of real quantum systems as having definite physical properties .
Humans live in many different worlds, each of which has its own representation in mind space. The world of the scientist will be called the physical realms. The laws of physics are an integral part of the real world, and humans acquire a natural understanding of these laws without regard to any mathematical formulation. While the experimental physicist studies the behavior of the real world, the theoretical physicist develops and studies its representation in the mathematical world (i.e., mind space). It is not necessary to know the mathematical equations to be able to carry out a physical investigation. This can be performed through observation and recording of the data numerically, and using the processes of interpolation and extrapolation. Practicing physicists usually find that they must adopt the roles of both the theoretical as well as the experimental physicist to achieve the aims of an experiment. Observers play a vital role in physics. They become important when their state of motion changes, or when their presence affects the results of the experiment. The observer can be either animate or inanimate. Unlike inanimate observers, animate observers have access to mind space, which allows them to make decisions from collected information.
The growth of modern science resulted in a radically new cognitive approach to many problems of classical philosophy. In the context of contemporary theoretical physics, if only one avoids easy apologetic, it is no longer possible to defend this version of epistemological empiricism that was defended half a century ago. Whereas in the 1930’s the traditional distinction between theoretical and observational terms was called into question, due to its arbitrary nature, in the 1980’s the basic philosophical opposition between material and immaterial (resp. between physical and mathematical) objects seems arbitrary since the very notion of matter appears nothing but a terminological relic of the bygone epoch.
In this chapter, I offer some personal reflections about the nature of reality, shaped by my work as a quantum physicist, my experimentation with psychedelic drugs during the 1960s, and my more recent studies of modern cognitive science. Traditionally, questions about the essential nature of reality are asked by philosophers. In the twentieth century, these questions were asked for the first time by scientists as well. During the first three decades of the century, the exploration of the atomic and subatomic world brought physicists in contact with a strange and unexpected reality that shattered the foundations of their worldview and forced them to think in entirely new ways. Quantum physics showed scientists “a new reality,” and from that time on, the nature of reality became a popular subject of discussion not only in philosophy but also in science. In recent decades, cognitive scientists took another radical step in the scientific conception of the nature of reality. They asserted that the features of our ordinary, everyday reality are not features of an independently existing world, but are created in the very process of perception. In a way this generalizes the influence of the act of perception on the perceived object, which was famously analyzed in quantum physics by Werner Heisenberg, to everyday perception. In other words, even our everyday reality is just one of many alternate realities.