Why does O'Brien claim that the party didn't believe in solipsism?

Question

In 1984, O'Brien claims that the party's philosophy is not solipsism. Why does he claim that? Was he telling the truth, and how does the party's philosophy actually differ from solipsism?

From chapter 3, section 3:

The belief that nothing exists outside your own mind - surely there must be some way of demonstrating that it was false. Had it not been exposed long ago as a fallacy? There was even a name for it, which he had forgotten...

"I told you, Winston," [O'Brien] said, "that metaphysics is not your strong point. The word you are trying to think of is solipsism. But you are mistaken. This is not solipsism. Collective solipsism, if you like. But that is a different thing; in fact, the opposite thing..."

Why does O'Brien claim that the party's philosophy is not only different than solipsism, but its exact opposite?

Answer 1

"Classic" solipsism states that only one's own mind can be certain to exist. It's at least partially an attempted solution to the problem of other minds: given that we can only observe other peoples' behavior, not access their consciousness somehow, how do we know that they actually are conscious? It's actually a surprisingly difficult question - imagine if you encountered a new species that's quite unlike humans and were trying to determine if its members were conscious; how would you go about testing that?

Another consideration here is that it's impossible to coherently doubt your own existence (because if you do doubt that, who or what's doing the doubting?), which is why proponents of solipsism can be certain of the existence of their own mind (if nothing else). A student once asked a famous philosopher "how do I know I exist?" The philosopher simply replied "who's asking the question?"

If you have "collective solipsism," you've essentially already admitted the actual existence of other minds, so in that sense it's the opposite.

With that said, like solipsism, the Party holds that they can actually alter external reality just by declaring it to be so (e.g. 2 + 2 = 5). O'Brien also extends the argument that, in a sense, the past only "exists" in written records and in peoples' memories; given that the Party controls both, they can (supposedly) rewrite history. This implies that history doesn't have an external reality beyond human consciousness; under this philosophy, if a tree falls in a forest and no one is around to hear it, it didn't make a sound.

Answer 2

I shall offer a different word on this, unconcerned with the technical issue of the meaning of a supposed epistemological solipsism, rather bringing out what I take to be Orwell's meaning. The plight of the individual under the "jackboot" of power.

This, by analogy, could be understood as the problem of legal positivism, in the ancient sense, that Justice is whatever the current law is. Here it is transferred to the existential plane. The individual losses their identity in the rapid surge of the collective, as guided by the activity of advanced and remote outposts, in this case, as embodied by the all-seeing O'Brien, master of the clearest logic. It's very like Antigone. There is someone absorbed, so to say, in their mores, for instance the feeling that it is terrible and impious not to bury one's dead kin. And O'Brien comes along and says, well, you know my dear, that is sheer superstition. We shall simply throw the body in the trash, quite sanitary isn't it? If the rational becomes indistinguishable from rationalization, trick, ideology, then the individual losses their mornings and becomes despondent, even despairs. Unless, of course, they are a hero, than they are shattered against the devastation of utter power and clockwork evil.