To think or believe is to engage in mental processes involving cognition, perception, or acceptance of an idea or concept.
What does it mean to think
Thinking involves the active process of using one's mind to consider, analyze, reason, and contemplate information or ideas. It encompasses various mental activities such as problem-solving, decision-making, and forming opinions based on logic, knowledge, and experiences.
Believing, on the other hand, involves holding something as true or accepting something as real, often without tangible proof or conclusive evidence.