> > > As a side note, note that beyond being a parallel line to the mirror plane, the preferred axis here is dependent upon the observer, not the mirror itself.
> > >
> > > --gremlinn

>
> Here's what I wonder: is it accurate to say that our perspective is along the horizontal axis because of the position of our eyes on our face?
>
> Iss "bi-clops" achar

Not exactly. Well, maybe yes. I suppose the right answer, relatively speaking, has to do with the fact that we see *horizontally*-reversed reflections only because a wall mirror is mounted in the *vertical* plane. And as gremlinn stated and as you infer, the result is dependent upon the viewpoint of the observer.

I go crazy trying to explain these concepts in plain English (shades of recollections in going nuts on Optics physics exams, actually). You try explaining this clearly: "With mirrors, the angle of Reflection is the angle between the reflected incident ray and the Normal to the surface of the mirror; the angle of reflection equals the angle of incidence. When dealing with Refraction (through a lens), the angle of Transmission is the angle between the transmitted ray and the surface Normal." The behaviour of light reflecting off of a mirror surface is tied to parallel *minimal* refraction between an air/media surface -- in this case, it's the silvery glass-aluminum interface of the mirror, which deflects back something like 93+% of the light striking its surface. (Or at least, that's the number I recall; it might be 99%).

And I've been talking only about vertically-mounted plane (flat) mirrors so far. They reverse things in the horizontal dimension (left-to-right) through a vertical plane of symmetry between the viewer and the mirror's surface. Things get even more interesting if you look at "parabolic reflectors," such as the polished concave bowl of certain soup spoons. Unlike a flat plane mirror, a parabolically reflecting mirror completely *inverts* images up-and-down instead of left-to-right. That's why you see your face upside down in the soup spoon; that's the image which hits your eye.

So yes, all these results are dependent on the perspective of a single observer whose eyes are located in one plane on one side of his or her head. Want to go crazy? Try thinking about what *God* would see when he looks into a mirror. An omniscient God can see everything at once from *all* perspectives; since he is self-described as having human eyes, when he uses them he'd see an infinite number of reflected images from all angles. He'd see infinite images even if the mirror were as small as a postage stamp.

Isn't this rather confusing? Mirrors ought to reflect a little before sending back images.

Wolf "wishes someone could explain that better" spirit