When discussing a 2D universe, many assume that an object would only be seen as "a line". This would imply that you are seeing the "edge" of the object. But, if there are only two dimensions, height and width, then there would be no edge, since there is no depth. So there would be nothing to be seen.
In a similar manner, it would seem that objects could not "bump" into each other, since they have no edge.
Could objects be "seen" in a 2D world?
EDIT: By "edge" I mean in the colloquial sense, such as the "edge on" view or flat side of a piece of paper.
Using the conventional idea of a drawing of a piece of paper being representative of 2D, we have to add the caveat that both the paper and the medium in which the drawing is done will have depth. But in a 2D world an object would, of course, have only two dimensions. Assuming we use the terms height and width for these two dimensions, as we use when describing a drawing, that would mean there is no depth. In which case an object could not be seen as a line or line segment. Perhaps it could be sensed in another way, such as magnetically, but this would seem to bring up other questions about laws of physics in a 2D universe.
So an 8x11 piece of paper would be 8" wide (width) by 11" high (height) and .0004 inches thick (depth). So the "edge/side" of the paper is .0004 inches thick in our 3D world but would be .0000 inches thick in the 2D world.
My question is whether we would actually be able to see a 2D object as a line or line segment, which is the usual interpretation, when it has no depth.