The subtitle of this book could be a bit misleading, suggesting as it does an assessment of the evidence for paranormal knowledge of the future. However, this isn't what interests Halpern, who is a Professor of Physics at the University of the Sciences in Philadelphia. Although his first chapter is entitled 'Ancient Auguries' and touches on the I Ching, the Delphic oracle, and Nostradamus, most of the book is concerned with modern science.
Einstein's treatment of time as the fourth dimension has evident implications for prediction and these are discussed in some detail. Some have claimed that Einsteinian physics affords room for time travel, but if this were possible it would generate paradoxes of various kinds and this implies that it is in fact forbidden. At the other end of the size scale, quantum theory also notoriously generates paradoxes and apparently has randomness built into it at a fundamental level, making prediction of atomic events impossible in principle. Many people (but, famously, not Einstein) have concluded that randomness is inherent in nature. Halpern outlines various ways of getting round this randomness that have been suggested.
A different sort of uncertainty also occurs in the world of classical physics; this has emerged in recent decades thanks to the study of the mathematics of chaos and complexity. Here we encounter systems that are entirely deterministic, not random, yet are in practice unpredictable. Laplace believed that if we knew the starting conditions of the universe we could then predict everything that happened afterwards, but this is now seen to be a delusion, because we can never know the initial conditions with sufficient accuracy and even tiny errors become progressively magnified as time passes. Halpern traces some of the implications of such theories for biology, with reference to computer models of biological systems.
Halpern sees predictability as a bridge resting on two pillars: one is made of simple regular mathematical models, such as those that allow us to predict lunar eclipses far into the future, while the other is statistical and concerned with randomness. Both these can be treated mathematically and used for prediction, but in between there are systems that are only partly predictable; weather forecasting is an example of these. But though there are limits to our ability to predict events, Halpern concludes optimistically, opining that the future holds great promise for us all. This contrasts rather remarkably with the tone of his earlier book, Countdown to Apocalypse, which ended on a very different note.