John Wheeler's delayed choice/quantum eraser experiment does not imply that we do not have a past. The experiment explores the behavior of quantum particles and the nature of their wave-particle duality. It challenges our intuitions about causality and the relationship between the past and future, but it does not negate the existence of the past itself.
In the delayed choice/quantum eraser experiment, the behavior of a quantum particle, such as a photon, can be influenced by choices made in the future regarding its measurement. It demonstrates that the properties of a particle, such as whether it behaves as a wave or a particle, can depend on the experimental setup and the information available to an observer.
The experiment involves interfering the paths of entangled photons and then manipulating the measurements performed on them. By erasing or revealing the which-path information, the experimenters can affect whether interference patterns are observed or not. However, it is important to note that the outcomes of the experiment are statistical in nature and do not invalidate causality or the existence of a consistent past.
The delayed choice/quantum eraser experiment challenges our classical intuitions by highlighting the non-intuitive behavior of quantum particles and the role of measurement and observation in determining their properties. It raises questions about the fundamental nature of reality and the relationship between observers and the observed phenomena. However, it does not undermine the existence of the past or invalidate our understanding of causality in everyday life.