If I'm interacting with somebody(say, via philosophical argument), we share a reality.
I think at this point it might be helpful to taboo "reality". I would rewrite your statement as something like this:
If my senses are transmitting perceptions that appear to be the result of my interaction with another agent, then, assuming that the agent does indeed have the ability to operate independently of myself, that agent and I share at least one communication channel that is common to both of us.
That sentence is unwieldy and, frankly, boring, but it does avoid making unwarranted assertions.
That said, going into this much detail is pro...
From Being a Realist (even if you believe in God):
My mother, who doesn't call herself a theist (I think she's agnostic), doesn't even accept realism. She doesn't even agree with this:
That's little more than tautologies here. Yet it elicited an impression of being forced to believe. I know because she told me about the totalitarian dangers from such narrow thinking.
I'm happy to have finally found the root cause of our ongoing disagreement, but now, how can I deal with that? It looks pretty hopeless, but just in case, does someone have a suggestion, or should I just leave it at that? (My ego doesn't like it, but giving up is an option.)
Now I'm relieved to know that in near mode, she's a complete realist. This craziness only shows up in far mode.