Which term refers to the belief system that maintains ancient traditions while accepting gradual changes?

The belief system that maintains ancient traditions while accepting gradual changes is best described by the term "Conservative." This perspective emphasizes the preservation of established customs and values, honoring historical practices, while still being open to the idea of gradual or incremental change. Conservatives typically advocate for a cautious approach to change, ensuring that any modifications do not disrupt the foundational aspects of their culture or belief system. This balance allows for a respect for tradition alongside an acknowledgment that change can be beneficial over time.

In contrast, the terms associated with progressive or liberal ideologies often lean towards seeking significant changes or reforms, which might not align with the conservative focus on maintaining existing values. The term "moderate" could describe someone who holds centrist views, possibly blending aspects of different ideologies, but it doesn't specifically capture the essence of valuing tradition while allowing for gradual evolution. Therefore, it is the term "Conservative" that accurately reflects the intended belief system in the question.