The concept of the relativity of time, or the idea that time can be experienced differently by different observers, has been a topic of philosophical speculation for centuries. While the specific phrase "relativity of time" may not have been used in ancient texts, there are discussions and ideas related to the relativity of time that can be found in various works throughout history.
One notable example is the philosophical work "Confessions" by St. Augustine of Hippo, written around the year 400. In Book XI of "Confessions," Augustine reflects on the nature of time and its relation to human perception. He ponders the question of what time is and discusses how our perception of time can vary depending on our mental state, suggesting a relative experience of time.
Another example can be found in the works of the ancient Greek philosopher Heraclitus (c. 535 – c. 475 BCE). Heraclitus is known for his philosophy of change and flux, and he famously stated, "No man ever steps in the same river twice, for it's not the same river and he's not the same man." This statement can be interpreted as an early expression of the idea that time is relative and constantly in flux.
Additionally, discussions of time and its relation to motion can be found in the works of medieval philosophers such as John Duns Scotus and William of Ockham. These philosophers explored the nature of time and raised questions about how the speed and motion of objects could impact the experience of time.
While these examples predate Albert Einstein's theory of relativity by many centuries, they demonstrate that ideas related to the relativity of time have been pondered and discussed throughout history, albeit from a philosophical perspective rather than a scientific one.