Particle physics studies highly complex processes which cannot be directly observed. Scientific realism claims that we are nevertheless warranted in believing that these processes really occur and that the objects involved in them really exist. This book defends a version of scientific realism, called causal realism, in the context of particle physics. The first part of the book introduces the central theses and arguments in the recent philosophical debate on scientific realism and discusses entity realism, which is the most important precursor of causal realism. It also argues against the view that the very debate on scientific realism is not worth pursuing at all. In the second part, causal realism is developed and the key distinction between two kinds of warrant for scientific claims is clarified. This distinction proves its usefulness in a case study analyzing the discovery of the neutrino. It is also shown to be effective against an influential kind of pessimism, according to which even our best present theories are likely to be replaced some day by radically distinct alternatives. The final part discusses some specific challenges posed to realism by quantum physics, such as non-locality, delayed choice and the absence of particles in relativistic quantum theories.

Particle physics studies highly complex processes which cannot be directly observed. Scientific realism claims that we are nevertheless warranted in believing that these processes really occur and that the objects involved in them really exist. This book defends a version of scientific realism, called causal realism, in the context of particle physics. The first part of the book introduces the central theses and arguments in the recent philosophical debate on scientific realism and discusses entity realism, which is the most important precursor of causal realism. It also argues against the view that the very debate on scientific realism is not worth pursuing at all. In the second part, causal realism is developed and the key distinction between two kinds of warrant for scientific claims is clarified. This distinction proves its usefulness in a case study analyzing the discovery of the neutrino. It is also shown to be effective against an influential kind of pessimism, according to which even our best present theories are likely to be replaced some day by radically distinct alternatives. The final part discusses some specific challenges posed to realism by quantum physics, such as non-locality, delayed choice and the absence of particles in relativistic quantum theories.

Quantum theory is widely regarded as one of the most successful theories in the history of science. It explains a hugely diverse array of phenomena and is a natural candidate for our best representation of the world at the level of 'fundamental' physics. But how can the world be the way quantum theory says it is? It is famously unclear what the world is like according to quantum physics, which presents a serious problem for the scientific realist who is committed to regarding our best theories as more or less true. The present volume canvasses a variety of responses to this problem, from restricting or revising realism in different ways to exploring entirely new directions in the lively debate surrounding realist interpretations of quantum physics. Some urge us to focus on new formulations of the theory itself, while others examine the status of scientific realism in the further context of quantum field theory. Each chapter is written by a renowned specialist in the field and is aimed at graduate students and researchers in both physics and the philosophy of science. Together they offer a range of illuminating new perspectives on this fundamental debate and exemplify the fruitful interaction between physics and philosophy.

Are the particles of modern physics "real" or are they virtual entities, their existence deduced merely by abstract theories? This book examines the continuing debate regarding the inner constitution of matter by exploring the particle concept in physics. It investigates if the particles of particle physics are real or not. Readers interested in the "true meaning" of such physical concepts will find this book informative and thought provoking.

What is science? -- Scientific inference -- Explanation in science -- Realism and anti-realism -- Scientific change and scientific revolutions -- Philosophical problems in physics, biology, and psychology -- Science and its critics.

Quantum theory explains a hugely diverse array of phenomena in the history of science. But how can the world be the way quantum theory says it is? Fifteen expert scholars consider what the world is like according to quantum physics in this volume and offer illuminating new perspectives on fundamental debates that span physics and philosophy.

Metaphysicians should pay attention to quantum mechanics. Why? Not because it provides definitive answers to many metaphysical questions-the theory itself is remarkably silent on the nature of the physical world, and the various interpretations of the theory on offer present conflicting ontological pictures. Rather, quantum mechanics is essential to the metaphysician because it reshapes standard metaphysical debates and opens up unforeseen new metaphysical possibilities. Even if quantum mechanics provides few clear answers, there are good reasons to think that any adequate understanding of the quantum world will result in a radical reshaping of our classical world-view in some way or other. Whatever the world is like at the atomic scale, it is almost certainly not the swarm of particles pushed around by forces that is often presupposed. This book guides readers through the theory of quantum mechanics and its implications for metaphysics in a clear and accessible way. The theory and its various interpretations are presented with a minimum of technicality. The consequences of these interpretations for metaphysical debates concerning realism, indeterminacy, causation, determinism, holism, and individuality (among other topics) are explored in detail, stressing the novel form that the debates take given the empirical facts in the quantum domain. While quantum mechanics may not deliver unconditional pronouncements on these issues, the range of possibilities consistent with our knowledge of the empirical world is relatively small-and each possibility is metaphysically revisionary in some way. This book will appeal to researchers, students, and anybody else interested in how science informs our world-view.

"I find the idea quite intolerable that an electron exposed to radiation should choose of its own free will, not only its moment to jump off, but also its direction. In that case, I would rather be a cobbler, or even an employee in a gaming house, than a physicist." -Albert Einstein A scandal hovers over the history of 20th century physics. Albert Einstein-the century's greatest physicist-was never able to come to terms with quantum mechanics, the century's greatest theoretical achievement. For physicists who routinely use both quantum laws and Einstein's ideas, this contradiction can be almost too embarrassing to dwell on. Yet Einstein was one of the founders of quantum physics and he spent many years preaching the quantum's importance and its revolutionary nature. The Danish genius Neils Bohr was another founder of quantum physics. He had managed to solve one of the few physics problems that Einstein ever shied away from, linking quantum mathematics with a new model of the atom. This leap immediately yielded results that explained electron behavior and the periodic table of the elements. Despite their mutual appreciation of the quantum's importance, these two giants of modern physics never agreed on the fundamentals of their work. In fact, they clashed repeatedly throughout the 1920s, arguing first over Einstein's theory of "light quanta"(photons), then over Niels Bohr's short-lived theory that denied the conservation of energy at the quantum level, and climactically over the new quantum mechanics that Bohr enthusiastically embraced and Einstein stubbornly defied. This contest of visions stripped the scientific imagination naked. Einstein was a staunch realist, demanding to know the physical reasons behind physical events. At odds with this approach was Bohr's more pragmatic perspective that favored theories that worked, even if he might not have a corresponding explanation of the underlying reality. Powerful and illuminating, Einstein Defiant is the first book to capture the soul and the science that inspired this dramatic duel, revealing the personalities and the passions-and, in the end, what was at stake for the world.

The Emergent Multiverse presents a striking new account of the 'many worlds' approach to quantum theory. The point of science, it is generally accepted, is to tell us how the world works and what it is like. But quantum theory seems to fail to do this: taken literally as a theory of the world, it seems to make crazy claims: particles are in two places at once; cats are alive and dead at the same time. So physicists and philosophers have often been led either to give up on the idea that quantum theory describes reality, or to modify or augment the theory. The Everett interpretation of quantum mechanics takes the apparent craziness seriously, and asks, 'what would it be like if particles really were in two places at once, if cats really were alive and dead at the same time'? The answer, it turns out, is that if the world were like that—if it were as quantum theory claims—it would be a world that, at the macroscopic level, was constantly branching into copies—hence the more sensationalist name for the Everett interpretation, the 'many worlds theory'. But really, the interpretation is not sensationalist at all: it simply takes quantum theory seriously, literally, as a description of the world. Once dismissed as absurd, it is now accepted by many physicists as the best way to make coherent sense of quantum theory. David Wallace offers a clear and up-to-date survey of work on the Everett interpretation in physics and in philosophy of science, and at the same time provides a self-contained and thoroughly modern account of it—an account which is accessible to readers who have previously studied quantum theory at undergraduate level, and which will shape the future direction of research by leading experts in the field.

Attempting to reinstate the common-sense idea that theoretical knowledge is achievable, the author of this text accounts for the genesis of the sceptical position, then introduces his argument for Minimalist Scientific Realism.