[GraffitiTim]

Funny, most people have the opposite question: they can't understand what it would be like to have aphantasia.

The way you're describing "knowing what a sphere is" and being able to describe it, is how I explain to people what aphantasia is like.

Consider the possibility, even if unlikely, that you yourself have aphantasia. It is common for people with aphantasia to not realize they have it until a conversation like this -- they simply assume they are experiencing what everyone else is experiencing, and that the concept of "visualizing" something is more metaphorical than it really is.

Can you really see a sphere when you're not looking directly at one, in any sense of the word? Or do you just know what a sphere looks like?

[OneWordSoln]

Or, perhaps, am I visualizing a sphere or simply remembering what a sphere looks like? It seems natural that we can only visualize what we have already seen, so would there not be a relationship with memory?