The more science tells us about the world, the stranger it looks. Ever since physics first penetrated the atom, early in this century, what it found there has stood as a radical and unanswered challenge to many of our most cherished conceptions of nature. It has literally been called into question since then whether or not there are always objective matters of fact about the whereabouts of subatomic particles, or about the locations of tables and chairs, or even about the very contents of our thoughts. A new kind of uncertainty has become a principle of science.

This book is an original and provocative investigation of that challenge, as well as a novel attempt at writing about science in a style that is simultaneously elementary and deep. It is a lucid and self-contained introduction to the foundations of quantum mechanics, accessible to anyone with a high school mathematics education, and at the same time a rigorous discussion of the most important recent advances in our understanding of that subject, some of which are due to the author himself.

From the celebrated author of Quantum Mechanics and Experience comes an original and exhilarating attempt at making sense of the strange laws of quantum mechanics. A century ago, a brilliant circle of physicists around Niels Bohr argued that the search for an objective, realistic, and mechanical picture of the inner workings of the atom—the kind of picture that had previously been an ideal of classical physics—was doomed to fail. Today, there is widespread agreement among philosophers and physicists that those arguments were wrong. However, the question of what that picture might look like, and how it might fit into a comprehensive picture of physical reality, remains unsettled. In A Guess at the Riddle, philosopher David Z Albert argues that the distinctively strange features of quantum mechanics begin to make sense once we conceive of the wave function, vibrating and evolving in high-dimensional space, as the concrete, fundamental physical “stuff” of the universe. Starting with simple mechanical models, Albert methodically constructs the defining features of quantum mechanics from scratch. He shows how the entire history of our familiar, three-dimensional universe can be discerned in the wave function’s intricate pattern of ripples and whorls. A major new work in the foundations of physics, A Guess at the Riddle is poised to transform our understanding of the basic architecture of the universe.

This book is an attempt to get to the bottom of an acute and perennial tension between our best scientific pictures of the fundamental physical structure of the world and our everyday empirical experience of it. The trouble is about the direction of time. The situation (very briefly) is that it is a consequence of almost every one of those fundamental scientific pictures--and that it is at the same time radically at odds with our common sense--that whatever can happen can just as naturally happen backwards.

Albert provides an unprecedentedly clear, lively, and systematic new account--in the context of a Newtonian-Mechanical picture of the world--of the ultimate origins of the statistical regularities we see around us, of the temporal irreversibility of the Second Law of Thermodynamics, of the asymmetries in our epistemic access to the past and the future, and of our conviction that by acting now we can affect the future but not the past. Then, in the final section of the book, he generalizes the Newtonian picture to the quantum-mechanical case and (most interestingly) suggests a very deep potential connection between the problem of the direction of time and the quantum-mechanical measurement problem.

The book aims to be both an original contribution to the present scientific and philosophical understanding of these matters at the most advanced level, and something in the nature of an elementary textbook on the subject accessible to interested high-school students.

After Physics presents ambitious new essays about some of the deepest questions at the foundations of physics, by the physicist and philosopher David Albert. The book's title alludes to the close connections between physics and metaphysics, much in evidence throughout these essays. It also alludes to the work of imagining what it would be like for the project of physical science-considered as an investigation into the fundamental laws of nature-to be complete. Albert argues that the difference between the past and the future-traditionally regarded as a matter for metaphysical or conceptual or linguistic or phenomenological analysis-can be understood as a mechanical phenomenon of nature. In another essay he contends that all versions of quantum mechanics that are compatible with the special theory of relativity make it impossible, even in principle, to present the entirety of what can be said about the world as a narrative sequence of "befores" and "afters." Any sensible and realistic way of solving the quantum-mechanical measurement problem, Albert claims in yet another essay, is ultimately going to force us to think of particles and fields, and even the very space of the standard scientific conception of the world, as approximate and emergent. Novel discussions of the problem of deriving principled limits on what can be known, measured, or communicated from our fundamental physical theories, along with a sweeping critique of the main attempts at making sense of probabilities in many-worlds interpretations of quantum mechanics, round out the collection.