What is reality when people lose themselves in virtual worlds?
Philosophy has not been able to settle in thousands of years what objective reality is, because our knowledge of the world keeps changing. Only God, who created the seen and the unseen, knows reality in full, and He makes it known through revelation.
Anyone who puts on a headset for an artificial world notices how easily image and reality can drift apart. But the question is much older than any technology. Even without a headset, we see things happening around us that may be quite different from what we think they are. Plato and Aristotle already asked what the world outside us really is, and found no final answer.
Take something as simple as water. We think we know it well. A thousand years ago anyone who said that something could catch fire in water would have been thought mad. Today we know that sodium can burst into flame in water. This is a property of water that people did not know for a very long time. And a thousand years from now, people will probably say of our present knowledge that it was very limited.
Some thinkers conclude from this that nothing is absolute and that everything changes with time. Islam sees it differently. There is a firm reality, but only One knows it fully, and that is its Creator. Without the Creator no one can understand creation perfectly. The first verse above calls God the Knower of the unseen and the seen.
Most of reality still lies behind a curtain for us. Our knowledge brings only a small piece of it into the light, a little here and a little there. The world of the unseen is far greater than the world we take to be real today.
So no one needs to despair over this question. Our senses and our devices only ever show us part of the picture. Whoever remembers this will mistake neither an artificial world nor their own knowledge for the whole truth. They will look for firm ground with the One who knows everything and makes Himself known through revelation.