What is the key evidence that the universe is not evolving into a more complex system?

The key evidence that the universe is not evolving into a more complex system lies in the second law of thermodynamics, which states that entropy, or disorder, tends to increase in isolated systems over time. This implies that energy disperses and systems become more disordered rather than more complex. Additionally, the observation of cosmic expansion and the eventual fate of the universe, such as heat death, suggests a trend towards uniformity and simplicity rather than increasing complexity. Thus, the overall trajectory of the universe points toward greater entropy rather than evolution into complexity.