At first, science thought that the world was made up of matter and that it, being the first cause, stood at the very beginning of the world as some un-creatable and non-destructible force, and that the world and life emerged gradually by the evolution of this matter. Later searches for the smallest particle of matter showed that matter actually does not exist, but that only energy does. This means that matter is only energy that is concentrated to the point of visibility, capable of behaving as a particle or a wave. So, according to science, it should mean that the answer to the question, “What exists?” is: energy.