When you say there are different forms, I think you mean different forms of solipsism. If that is what you meant, then I think this discussion is circling back

When you say there are different forms, I think you mean different forms of solipsism. If that is what you meant, then I think this discussion is circling back to my original post, in this sense: you are demonstrating that one can have a rational discussion about it. What I am not so convinced about, however, is whether one could rationally be a solipsist - to really (that word again!) believe that (to pick one particular definition for concreteness) the self is the only reality. In this regard, the inability to disprove solipsism is not sufficient to be a justification for believing it; if it were, the mirror argument would equally justify not-solipsism, and so a rational person should regard both arguments as inconclusive. I only mentioned brains-in-vats and simulations because I wondered whether mypalmike had them in mind, and only to say that I don't think it matters whether or not the putative solipsist is either of these things. Rather than continue in this vein, I will point you to an article which concludes with the section "The Incoherence of Solipsism": One might even say, solipsism is necessarily foundationless, for to make an appeal to logical rules or empirical evidence the solipsist would implicitly have to affirm the very thing that he purportedly refuses to believe: the reality of intersubjectively valid criteria and a public, extra-mental world. There is a temptation to say that solipsism is a false philosophical theory, but this is not quite strong or accurate enough. As a theory, it is incoherent. What makes it incoherent, above all else, is that the solipsist requires a language (that is, a sign-system) to think or to affirm his solipsistic thoughts at all. https://iep.utm.edu/solipsis/ https://iep.utm.edu/solipsis/