The Heisenberg uncertainty principle suggests that certain properties of particles, such as position and momentum, cannot be precisely measured simultaneously, leading to inherent randomness in nature. This indeterminism implies that if one were to "roll back time," events might not unfold the same way, challenging the notion of a predefined future. Measurement plays a crucial role in quantum mechanics, as properties only manifest when observed, raising questions about the nature of reality and the observer's influence. The debate continues between interpretations like the Copenhagen interpretation, which embraces indeterminism, and hidden variable theories that seek deterministic explanations. Ultimately, quantum mechanics reveals that our understanding of reality is limited by the measurement process and the probabilistic nature of particles.