The compatibility of the block universe theory and the many-worlds interpretation in quantum mechanics is a topic of ongoing debate among physicists and philosophers. While both theories deal with different aspects of reality, they have conceptual differences that make their integration nontrivial.
The block universe theory, also known as eternalism or the four-dimensional view of time, posits that past, present, and future events all exist as equally real and ontologically on par with each other. According to this view, time is merely a dimension, and our perception of the passage of time is an illusion. The block universe theory is often associated with the theory of relativity, which treats time as a fourth dimension and combines it with the three dimensions of space to form a four-dimensional spacetime framework.
On the other hand, the many-worlds interpretation in quantum mechanics suggests that whenever a quantum event occurs, the universe branches into multiple parallel universes, each corresponding to a different possible outcome of that event. This interpretation is one of several proposed explanations for the observed behavior of quantum systems, such as the wave-particle duality and the probabilistic nature of measurements.
The challenge in reconciling these two theories arises from the fact that the block universe theory assumes a fixed, deterministic view of reality, where all events are already determined and exist simultaneously, whereas the many-worlds interpretation introduces a proliferation of parallel universes to accommodate all possible outcomes of quantum events.
Some attempts have been made to reconcile these views, such as suggesting that the branching of parallel universes in the many-worlds interpretation occurs within the block universe framework. However, achieving a fully satisfactory integration remains a subject of ongoing research and philosophical inquiry.
It's worth noting that these theories involve complex and abstract concepts, and different interpretations and viewpoints exist among experts in the field. The nature of time and the foundations of quantum mechanics are still active areas of investigation, and future advancements may lead to a deeper understanding or alternative perspectives on these matters.