What unites the theory of the large with the theory of the small?

Theories of the large, such as general relativity, and theories of the small, like quantum mechanics, are united by the search for a fundamental understanding of the universe's workings. Both frameworks aim to explain natural phenomena, albeit at different scales—cosmic and subatomic. Efforts like quantum gravity and string theory seek to bridge the gap between these two realms, suggesting that the underlying principles governing both large-scale structures and tiny particles might be interconnected. Ultimately, a unified theory could provide a comprehensive description of all physical laws.