How much of what you see is a hallucination?

The definition of hallucination given by Encyclopedia Britannica goes as follows: "the experience of perceiving objects or events that do not have an external source, such as hearing one's name called by a voice that no one else seems to hear. A hallucination is distinguished from an illusion, which is a misinterpretation of an actual stimulus." However, it seems that hallucinations have much more in common with our everyday perceptions. Maybe, we should become more conscious of the subtle layers of reality and open our eyes to other perspectives. Because, after thousands of years invested in philosophy and science there is still no definite distinction between reality and dream. One of the best though was conceived by René Descartes. He speculated that the only solid argument that makes the first different from the latter is the presence of some regularity in the memories from when we are awakened. However, memory is a really elusive phenomenon.

Below you can enjoy a short video on the topic of hallucination.