What does no death of theories mean?

The phrase "no death of theories" suggests that scientific theories, once established, do not simply disappear or become irrelevant; instead, they continue to influence and inform new research and understanding. Even as new theories emerge, older ones may still hold value or be applicable in certain contexts. This reflects the cumulative nature of scientific knowledge, where theories evolve rather than vanish. Ultimately, it highlights the enduring impact of foundational concepts in the ongoing pursuit of understanding.