The problem of absolute simultaneity in the special theory of relativity

The special theory of relativity negates the concept of absolute simultaneity, leading to a significant challenge for the A theory. This issue arises from the inability to determine simultaneous events across different frames of reference due to the constant speed of light and lack of absolute rest. As a result, determining what is present or real becomes relative, posing a fundamental obstacle for theories like presentism and challenging the notion of a universal reality.