It depends on whether you think of it as moving the content, or moving a window over the content. When reading a piece of paper, do you move the paper upwards,

It depends on whether you think of it as moving the content, or moving a window over the content. When reading a piece of paper, do you move the paper upwards, or do you move your eyes downward? What does pressing the "down arrow" key do, and should moving down on a trackpad move in the same direction as the "down arrow" key? Personally, I have a physical consideration: scrolling down in a document is more common than scrolling up, and to me moving the fingers down over the trackpad feel more comfortable than moving the fingers up, so I use normal scrolling instead of inverted scrolling.