This argument was given by an Anglican Bishop, writer and philosopher George Berkeley, whose theory was that perception created our reality. According to this theory, the falling tree produces sound certainly, although there is no one to hear it, because God, the creator of everything, would hear and perceive it. Furthermore, Berkeley claims that everything we think we know, in fact, does not exist at all because everything that is "out there" as a set of perceptions, interpretations and sensations, which God turns into "ideas." In other words, you've seen something or not, you've heard something or not, it's a matter of perception, but everything as a perception is already there "somewhere" as a non-material one, which God turns into material, to reach us, to our perception. This example of the falling tree is in fact a philosophical experiment that Berkeley used as an argument to show us the philosophical position of immaterialism.