Marc, you can't know. In philosophy, it's called a simple concept. For instance, if you didn't know what the color blue was, it would be impossible to have it explained to you. Complex concepts can be explained, for example, a red line. If you know the simple concepts involved (red and line) then you can imagine a red line, but if you have never experienced the color red, or a line, then it will be impossible to explain it.
Alex put this well when I spoke with him about the incident. It would be like explaining a certain shade of color to a blind man.