Once Before Time - Martin Bojowald [1]
I thank Elisabeth and Stefan Bojowald for their critical reading of an early version of the book, and for some hints such as those about cyclic images in Egyptology. In conceptualizing some passages, I was inspired by the tranquillity of their retreat at the edge of the Eifel Range.
STATE COLLEGE, PENNSYLVANIA
APRIL 2008 / SEPTEMBER 2009
INTRODUCTION
The more abstract the truth you want to teach, the more you must seduce the senses to it.
—FRIEDRICH NIETZSCHE, Beyond Good and Evil
The goal of science has always been nothing less than as complete an understanding as possible of the laws of the world—nothing less than as unequivocal a description as possible of what we see and probe. Nothing less than coming as close as possible to what can be considered truth—in a nonsubjective way, the only way that counts.
Over the course of the last century, physical research in particular has progressed far to build a dominant theoretical edifice: quantum mechanics and general relativity. Understanding nature on the large and the small scale has become possible, from the whole universe in cosmology all the way down to single molecules, atoms, and even elementary particles by means of quantum theory. Precise descriptions and a deep understanding of a wide variety of phenomena have resulted, and they have been spectacularly confirmed by observations. Especially during the past decade, this hallmark of scientific success has also been achieved in the cosmology of the early universe.
Aside from its technological relevance in almost all areas of everyday life, an unmistakable sign of the quality of scientific progress is that for quite some time, some fields of scientific inquiry have touched upon questions traditionally held to be in the realm of philosophy (giving rise to the term “experimental metaphysics,” coined by the physicist and philosopher Abner Shimony). Since Aristotle, the aim of all theory has been to shed light on general phenomena and to understand their causes, in contrast to collecting disconnected bits of knowledge. Philosophy, by contrast, asks for the deepest origin or principles of all that exists. In this sense, the merging of some physical and philosophical issues can in fact be considered a distinguishing feature of scientific progress. When physics pushes ahead to such questions, it gains a position that allows it to contribute to discussions of far more general—and more far-reaching—interest. In the context of a combination of cosmology and quantum theory, the most important question is that of the emergence and the earliest phases of the universe, a question that has preoccupied humankind ever since the beginning of philosophy—and even before.
Other questions that have engaged thinkers over the centuries, and that remain of great significance, in quantum theory as well as general relativity, are the role of observers in the world and the question of what can be observed at all and what perhaps cannot. In cosmology, the entrance of physical research methods means the emergence of empirically testable scenarios for the whole world. The big bang model is founded on general relativity—as a description of space, time, and the driving gravitational force—as well as on quantum theory, which is indispensable to understanding properties of matter in the early universe. From all this, a breathtaking explanation results for the successive emergence of all matter—nuclei, atoms, and compound material objects all the way up to galaxies—out of an extremely hot initial phase.
At this rarefied place, the limits of the established worldview become visible. In spite of all their successes, general relativity together with quantum theory, as they are being used today, do not provide a complete description of the universe. When one solves the mathematical equations of general relativity in hopes of finding a model for the temporal evolution of the universe and its long-term history, one always reaches a point—the so-called big