Can something exist and not exist at the same time ?
The answer has to do with the difference between rational and empirical theories, with the ambiguity of simultaneous potentiality and actuality more common to empirical. This is due to empirical tending to use statistical modeling and a black box; Schrödinger's cat.
Let me give an example, at one time it was thought that earth was flat and was the center of the universe. The sun was observed to moved from east to the west. They could empirically plot the daily and annual path of the sun. Empirical theory does not have to be right in terms of reality. It just the placeholder for the best curve through the observational data, even if it misses data points. The flat earth center theory can remain, since empirical does not challenge that theory. While the good data plot appears to support it. Nothing is fully connected by reason. It is more of a method and careful documentation.
A rational theory is developed differently. It tries to explain what it sees, rationally, and predicts future data, before experiments, to see if this data touches the rational math curve. One experimental one data point will tell you, if you are correct, since the curve comes first based on reasoning in your head. Empirical draws the curve secondary and needs many more data points for a better curve. Then we explain the curve with the earth being the center, but not due to logic, as a placeholder since the data curve appears to average what we observe with all that data. We can use a mythological explanation since the data and curves is about observations and not logic.
The idea of the flat earth being the center and the sun rising in the east and sets in the west, can now be plotted. However, to the rational mind this scenario raises the question where does the sun go, when the sun sets? Does it burrow inside the flat earth, move eastward and come out the east side. to rise again? One may not be allowed to ask that question. We cannot plot that data, since we cannot see it. It might be seen as moot point.
However, you can still use reason. This question would be easier to explain, if the earth was spherical and the sun was orbiting like the moon. We would see only part of its circular journey. This is logical, but is not yet the final model. However, it does not ignore the hidden half of the data we cannot empirically see or use. We can make a math model; circle, to include the dark side we cannot see. I am working outside the box; black.
Based on this rational theory, I think up an experiment to prove my thesis based on my calculations. I will go 100 miles east and 100 miles west to gather data I cannot see from where we are. Will the sun continues on, does it burrow, or does drop down over the edge of the earth, and travel or bore below and rise in the east? What I see is sun continues west; spherical path? Now I can calculate sunrise in other places to the minute and can prove or disprove my theory with one data point.
Empirical by fitting the curve to the data gives a practical tool, but it leaves unanswered questions; hidden inside the black box. This is where Schrödinger's cat appears. The empirical theory was not a product of reason that tries to address these questions in advance. The rational model tries to iron out these things in advance. If an empirical theory comes first, the theory may not fit all the questions, and progress can stall, if the correlation seems to work; Evolution and genetics. All the missing links get to remain in the black box; alive and dead. Plus we see data only after the fact, due to the unanswered question still inside the box.
