Just to show you how differently we think, I was quite astonished that you would even think of trying to communicate about any concept which you held to be incommunicable. If you yourself truly believe a concept to be incommunicable, then any attempt by you to communicate it can only be regarded (from your perspective) as noise, supplying nothing but distraction to any communications.
As far as I am concerned, I have no interest whatsoever in any concept which cannot be communicated for I clearly have no chance of ever understanding such an idea. I am of the opinion (and everyone has a right to their opinions) that anyone who thinks they can objectively deal with anything they cannot communicate is being quite gullible.
That being the case, let us (at least between ourselves) constrain any discussions to communicable concepts only!
Then, as I understand it at the moment, we now have 4 concepts about which we have at least some semblance of agreement concerning what is meant when I use the terms:
1. The Universe --- absolutely everything!
3. Sense Impressions --- the information from which your Mental model (as per Paul's suggestion) of The Universe is built!
2. Your Mental model of the Universe! (I have absolutely no idea how I missed that "you're" .. sorry about that!)
4. That any aspect of the above which is not communicable is not part of this discussion.
If that is indeed the case, would you agree that this same identical circumstance (collection of concepts) defines a rational position between myself and any person with whom I could have a logical discussion?
Please realize that these definitions still in no way constrain what your mental image of the Universe actually is, nor what your Sense Impressions actually are! Those two issues have still been left entirely open! By constraining what we will talk about to be communicable concepts only, we have done nothing except constrain the outcome of our communications to include only communicable concepts. To expect anything beyond that is to expect to communicate incommunicable concepts; an expectation which any rational mind should recognize as pure folly.
Have fun -- Dick