The concept of time travel often involves complex and paradoxical situations, and the scenario you described is commonly known as the "grandfather paradox." According to this paradox, if a person were to travel back in time and meet their past self, it raises questions about what would happen and how it could potentially impact the timeline.
There are several theories and interpretations regarding time travel, but here are a few possibilities:
Self-Consistency Principle: According to this principle, any actions taken by a time traveler in the past would have already been a part of the timeline, and they would have no significant impact on changing the future. In this case, the time traveler meeting their past self would simply be an event that was meant to happen and would not result in either of them disappearing.
Multiple Timelines: Another interpretation suggests that when a time traveler goes back in time and interacts with their past self, it creates a branching of timelines, creating two separate realities. In this scenario, the time traveler and their past self would exist in separate timelines, and neither of them would disappear.
Temporal Paradox: Some theories argue that a paradox would occur if a time traveler were to meet their past self. This paradox suggests that the very act of meeting oneself in the past could create a contradictory situation that could disrupt the fabric of reality. As a result, it is often speculated that one or both versions of the time traveler might disappear or cause some other unpredictable consequence.
It's important to note that time travel is purely speculative at this point, and there is no scientific consensus on its feasibility or the specific consequences that would arise from such encounters. The implications of time travel are still the subject of ongoing scientific and philosophical discussions, and various theories exist with different interpretations of how time travel might work.