Ok... Solipsism is the thought that perhaps you are the only being in existence and that everything you percieve and experience is but a figment of your imagination. It has long been claimed to be unfalsifyible. But here is why solipsism cannot be. We have to attack it from several angles so bare with me. First rationale: If you are truly the only thing in existence, then there can be no such thing as temporality (ie the world of opposites, comparisons, and cause and effect). In other words YOU ARE IT and you haven't a molecular structure or atoms- the existence of these would imply that you exist in some kind of temporal system that precedes your existence thus suggesting that you are not truly alone. So if it is the case then that you are truly singular in every way then you have nothing to compare yourself to. Without something to compare yourself to you would not and indeed could not feel anything that would even remotely suggest temporality such as feelings like hatred, fear, want or desire. The only thing that you would feel would be utter peace and even that would not be definable. As the sole conscious and singular entity you could only be self aware. There would be no possible way for you to experience anything or even concoct the concept of experiencing something since that would imply that you somehow can comprehend the idea of the existence of things other than yourself. Some might claim that over eons and eons it is possible that something could possibly evolve into existence that happens to possess the capacity for false emotions and true solipsism. But in truth if you are all that is and you are truly singular, this ultimately means that you are "stable" and you cannot evolve since evolution would require that you respond to your environment and you don't have one. At best you are surrounded by empty space and this empty space would mean nothing to you since there is nothing external of you for you to percieve and thus define the concepts of distance and hence space. So if you take it to the extreme and suggest that you TRULY are alone, then solipsism is not possible. Second rationale: If you are a biological organism or if you are simply composed of more than one particle, then you by definition exist within a temporal system. One might suggest that an organism could evolve in this case over eons and eons that possesses the capacity for true solipsism but all of your emotions including want, desire, fear, love and hatred would had to have evolved as a result of a real perception of other entities. Otherwise these emotions could never be defined. Our basic emotions mean what they mean to us because of how they have served us and they therefore could never have evolved independently of an external reality.