School of thought of the Grandfather Paradox:

What if you go back into time when your granddad was about to meet your grandma for the first time and convince him not meet her at all?? Then how would you be born?? If we go ahead thinking this. Two sets of the universe would be formed, First one when your granddad meets your grandma and the family continues. Second one when your granddad does not meet her at all. However, it is strongly believed that this could not be possible because the universe would ensure to keep up its consistency of time. So have you ever regretted your decision in the past?? Don’t do that because you took that decision matching the consistency of universe. This is what we curtly refer to as destiny. This is not based on any fundamental of science. After this fantasy concept let us look from the point of view from physics.