The question of whether all events in the universe are absolutely determined by physical laws is a topic of ongoing scientific and philosophical debate. It is closely related to the concept of determinism and the nature of causality.
In classical physics, the Laplacean determinism suggests that if we have complete knowledge of the initial conditions of a system and the laws governing its behavior, we can predict with certainty the future state of that system. However, with the advent of quantum mechanics, this deterministic view has been challenged.
Quantum mechanics introduced the concept of inherent randomness at the microscopic scale. According to the Copenhagen interpretation, quantum systems exist in a superposition of states until they are observed, and the act of measurement "collapses" the system into a definite state. This randomness is fundamentally different from classical determinism.
When it comes to the nature of the entire universe, including gravity, a quantum theory of gravity is currently under active exploration. The current framework for describing gravity, Einstein's general theory of relativity, is a classical theory and does not incorporate quantum mechanics. A complete theory of quantum gravity would be necessary to fully understand the behavior of the universe at extremely small scales and high energies, where both quantum effects and gravitational interactions are significant.
However, whether a quantum theory of gravity would definitively settle the question of determinism is uncertain. It is possible that even with a fully realized quantum theory of gravity, inherent randomness or probabilistic aspects may still persist.
Ultimately, the question of determinism versus indeterminism and the absolute nature of physical laws is a complex and philosophical one. It is an area of active research and inquiry, and scientists and philosophers continue to explore and debate these fundamental aspects of our understanding of the universe.