Symbols - What does heaven look like
The Ivory tower takes its symbolism from the Tower, but specifically as related to our own collections of data residing in Memory. Just like Towers, they may be seen in spiritual experiences attached to castles, again a rather neat and consistent symbolism.
The term Ivory Tower [is] used to designate a world or atmosphere where intellectuals engage in pursuits that are disconnected from the practical concerns of everyday life. As such, it usually carries connotations of a disconnect from the everyday world……………
In the Odyssey (XIX.560) two kinds of dreams are distinguished, as they exit from the realm of Morpheus: true dreams exit through the Gate of Horn, and false dreams through the Gate of Ivory. Virgil put the image succinctly:
There are two gates of sleep. One is of horn, easy passage for the shades of truth; the other, of gleaming white ivory, permits false dreams to ascend to the upper air. (Aeneid VI.893-896)
You will need to understand the symbolism of the twin horns to understand what this means.