Some called it "progressive revelation", but often such "progress" stops somewhere, usually in the past. If it has stopped, then how do we make of our developmental understanding, which supposedly on-going?
Is revelation really progressive or our understanding that is progressive? Both? If both, then what doctrinal stability do we have at all?
On deeper reflection, could it be that "heaven" is really nothing more than just our developmental understanding?
Could it be that it is just a "[sic]", just a theory without deeper meaning other than the fact that the word "heaven" is being uttered? And our developmental understanding is our attempt to make sense of that utterance?
This investigation doesn't of course stop only at "heaven". More significantly, the same should be asked on the often-used word "spiritual".
Getting at an answer would not only be a linguistical and psychoanalytical but also theological and philosophical breakthrough.