For anyone unfamiliar with what Carl Sagan is talking about here.
Indeed, one might even say, solipsism is necessarily incoherent, a self-refuting idea, for to make an appeal to logical rules or empirical evidence the solipsist would implicitly have to affirm the very thing in which he or she purportedly refuses to believe: the 'reality' of intersubjectively valid criteria, and/or of a public, extra-mental world.
Sagan never believed in solipsism, but he did like the implications that our perceptions do not necessarily reflect our reality (actually he just liked novel thoughts in general). But really, it's a pointless debate. Whether the reality we perceive is real or not, we have no choice but to assume that is is real.