According to the prevailing, mainstream, 'scientific'/ materialist assumptions - communication is not possible.
This is because these assumptions entail that (to summarise Owen Barfield in his essay The Coming Trauma of Materialism):
1. 'Nature' is a separate autonomous and objective realm - which can be affected by Man only from outside. That is, Nature is something that precedes man, and always has gone one separately from human awareness and direct-participation. In effect, Man is an optional-extra for Nature.
2. Each individual Man is a separate part of the objective system of Nature - we aren't connected in any ultimate or fundamental way; because...
3. One mind can communicate with another mind only via the medium of physical processes.
Most people haven't connected the dots sufficiently to realise that the standard explanations of communication rule-out any possibility of communication (except by sheer random chance - which is, of course, not communication at all) since the scheme has multiple steps of representations, none of which are reliable, none of which can be checked.
In sum, according to the usual scheme, we have no idea whether what we perceive is real, distorted, partial or just imaginary (an hallucination, perhaps) - and when we send out a communication we have no idea whether or not our communication has been understood (nor even received) - not least because any check on understanding has to use the same chain of uncertain representations the validity of which we are attempting to check.
What this means is that we cannot know whether somebody else is thinking the same thing as we ourselves are thinking. Hence our minds are utterly isolated from everything else - including all other people.
This creates a reductio ad absurdum for what we suppose to be human discourse, and indeed human existence. Fairly obviously, if communication is not possible, then hardly anything has any point to it - certainly not what I am currently writing!
Why then is such an absurd and self-refuting metaphysical scheme so utterly dominant in modern Western society? Why do we simultaneously assume (in our actions) that communication is possible, yet (in our assumptions) that communication is impossible? Why does not this incoherence lead to abandonment of materialist metaphysics?
The reason is that if we explicitly were to regard (as, surely, we ought to!) communication as possible; then this has consequences which would be extremely disruptive to the materialist basis of modernity.
In particular, if communication is possible, then we must each be able to think exactly the same thought as another person. Real communication involves a direct sharing of thoughts.
What I mean is that if you and I are to be in communication, then when we think of a triangle, a face, the theory of evolution by natural selection or anything else... we must both be able to think exactly the identical thought.
(Not a similar thought, nor a precise copy of a thought; but exactly the same unit of thought.)
This, in turn, means that the thought cannot be inside either or both of our minds; but must instead be 'located' in some realm to which we both have access. In effect, we could only think exactly the same triangle (and therefore experience communication) if both of us were thinking in some kind of common 'space' where this triangle was located.
Now, the specifics of how this might work - e.g. what kind of a realm the triangle exists in and how each of our minds might get access to it - are conjectural and metaphysical (and therefore partial, incomplete and simplified); but the basic idea of the possibility of more than one person simultaneously thinking the same thought seems hard to deny - if, as I say, real communication is to be regarded as a possibility.
(Leaving aside the next, and 'epistemological' question of how we would know that any particular example was a real communication. First the metaphysical assumptions allowing the possibility must be established, before epistemology can be discussed.)
So we reach the striking, and radically disruptive, conclusion that if communication is possible, then people must be able to think outside of their own minds in some common domain which is multiply accessible; and that this must be possible outside of the material world and therefore outside of the 'five senses'.
Furthermore, that real communication is (at least at present) undetectable and unmeasurable - but works by entirely different routes and means.
Since pretty much everything depends on communication, the conclusion apparently forced upon us is that we absolutely depend upon some kind of direct, undetectable and unmeasurable, yet universal, shared realm of 'thoughts'.
So you can see why the incoherence of modern ideas of communication are able to survive decade after decade, despite being necessarily wrong and senseless - the alternative is so profoundly at odds with modern culture as to be (for most people most of the time) literally un-thinkable.
