The grandfather paradox raises questions about causality from "summary" of Time Travel in Einstein's Universe by J. Richard Gott
The grandfather paradox is a classic example that demonstrates the potential problems that can arise when contemplating time travel. Imagine a scenario where a person travels back in time and prevents their grandfather from meeting their grandmother. This would mean that the time traveler's parents would never have been born, which in turn means that the time traveler themselves would never have been born. This creates a paradoxical loop where the time traveler's existence is both necessary and impossible simultaneously. One of the key issues that the grandfather paradox raises is the question of causality. Causality is the concept that an event is caused by a preceding event, and it plays a fundamental role in our understanding of how the world works. However, when time travel is introduced, causality can become muddled and paradoxes can arise. In the case of the grandfather paradox, the causal chain is disrupted by the time traveler's actions, leading to a self-referential loop with no clear beginning or end. This paradox highlights the potential consequences of changing the past through time travel. If the past can be altered, it raises questions about the nature of reality and the reliability of cause and effect. If events can be changed at will, then what is to stop someone from altering history in a way that is advantageous to them, regardless of the consequences for others?- It also forces us to confront difficult questions about the nature of reality and the limits of causality. Ultimately, the grandfather paradox reminds us that the past is not something to be taken lightly, and that our actions, even those done with the best of intentions, can have far-reaching and unpredictable consequences.
