Chapter 4

Stephen Hawking discusses the concept of scientific determinism, which proposes that if we had enough information, we could predict all events based on scientific laws. However, advances in quantum mechanics, such as the discovery of the uncertainty principle, have shown that the future cannot be completely predicted. The uncertainty principle states that if the position of a particle can be accurately calculated, then any attempt to measure its velocity will be less accurate and vice versa. This means that scientists must examine a "quantum state" that combines both position and velocity in order to predict a number of possible outcomes and their relative probability. The concept of wave-particle dualism, in which particles sometimes behave like waves and waves sometimes behave like particles, also challenges the idea of determinism.