Solipsism is the theory that the only thing that truly exists and can be proven to exist is the self.
I had thought for a long time that solipsism was a very difficult position to defeat. It seemed like a failure to make useful distinctions and to recognize continuity, but the burden of proof is always on the non-solipsist. The solipsist can always reasonably claim, no, that is just a figment of my imagination.
It occurred to me though that there is a positive claim in solipsism:
Every part of my train of thought can be explained solely in terms of my mind's workings.
Well, part of how I characterize myself is in terms of my limitations. For example, I am a poor philosopher. I have never had any formal training in philosophy, can't define the term "philosophy", and many of my arguments would seem sophomoric to real philosophers were such things shown to exist.
If I am a poor philosopher, and solipsism is true, how can I explain my perception that I have read and heard arguments by better philosophers? Could I be the source of philosophical arguments which require more competence than I perceive myself to have?
Perhaps, I am just mistaken about my philosophical talents, but I also believe myself incompetent at many other things: art and music appreciation, literary criticism, poetry, non-discrete math, (though I am loathe to admit it) discrete math. I believe that I have read or heard better accounts of these topics than I am capable of giving.
I could be wrong about my abilities on a few of these scores, but taking all these limitations into account, either
- I am not the one who exceeds my perceived limitations in these arenas, or
- the only mind that exists is not "me" because it differs in many attributes (talent at philosophy, etc.) from my understanding of myself.
The solipsist might respond, "the self is just unaware of what the self is", but if the solipsist is not correct about the defining attributes of the self, then the solipsist claim that "the self is" is meaningless. Since, if solipsism is true, the solipsist is the self, then the self's misapprehension about defining attributes of the self means that the self is not referring to something that exists when it says "the self is".
Which gets to the question of what is a defining attribute of the solipsist's "self"? If solipsism is true, the "self" is mind and there is nothing but that mind, so the defining attributes must be mental attributes. If a thing has non-mental attributes, then it is not pure mind. The limitations I discussed above are defining attributes of the self and I have observed too many of them broken.
Therefore, because my mind's workings cannot be explained purely in terms of my mind, the self cannot have the defining attributes of "self" that it has in mind when it says "the self is". If it is not even the case that "the self is", then the self cannot be all that is. Solipsism fails.
In short, the self cannot be the only thing that exists because it is evidently not the self that it thinks it is.