Let's say we have an electric field, (ax, 0, 0). (a is a constant) The divergence of the field is a, so the charge density is a*epsilon. This implies a uniform charge density, but the field only points in one direction! Furthermore, it switches directions at the x-axis. But that's weird, since the location of the x-axis and therefore the change in direction is dependent on where you place your coordinate system, but the field of a uniform charge density shouldn't be dependent on something like that! Also, what if you made the field (ax, by, cz) (where a, b, c are constants) The charge density is still uniform, (a+b+c)*epsilon, but now, there's some kind of radial field, even though there's still a uniform charge density! I don't understand what's going on.