How can you otherwise talk about this:
“There is, mendicants, that dimension where there is no earth, no water, no fire, no wind; no dimension of infinite space, no dimension of infinite consciousness, no dimension of nothingness, no dimension of neither perception nor non-perception; no this world, no other world, no moon or sun. There, mendicants, I say there is no coming or going or remaining or passing away or reappearing. It is not established, does not proceed, and has no support. Just this is the end of suffering.” (Ud8.1)
Do you believe Buddha talks here about something he does not really know but conceives to be? Postulates to exist?
Suppose Buddha talks here about something he directly knows, can this be known by vinnana?
How can one know the end of the world in this body ? Can Vinnnana know this?
It seems Impossible to me. For me it is very unlikely the Buddha refers here to some future vision of the end of the world, or no rebirth.
It is more or less obvious, also in science, that knowing does not have to refer to an awareness of something (vinnana). Moreover, it is said that most knowing stays below the level of vinnana but still influences choices, behaviour, metabolism, emotions etc. This can even be used in a manipulative way. Knowing can be subtle and vinnana is only the coarse kind of knowing. It is very unlikely that we really know how body and mind are influenced all the time and are only aware of the coarse things.