Yes, that's implicit in what I've been telling you from the start.Good, this is the first assumption beyond evidence. It is unknown whether you live in a real universe or an unreal one.
BUT I've also pointed out that YOU assume there's a world external to the self, because if you didn't, you wouldn't post here.
AND I've also pointed out that YOU assume our senses are capable of informing us about that world, because if you didn't, again, you wouldn't post here ─ which involves reading my posts and regarding them as real and responding to them.
AND I've also pointed out that YOU assume reason is a valid tool, since you use reason here.
AND SINCE WE AGREE ON THOSE ASSUMPTIONS we can proceed to talk, with that as the background.
YES, THAT'S WHY IT HAS TO BE AN ASSUMPTION. The idea of evidence arises only AFTER we make all three of the assumptions above.You can assume that you live in a real one, but that doesn't make it real with evidence.
So what, since you agree with and act on the basis of those assumptions ─ just like everyone else?It makes it real that you assume you live in a real universe. The same with materialism, that is also an assumption and you can't demand evidence for other assumptions than materialism. How? Because assumptions are without evidence. That is what makes them assumptions.