Why objects in a mirror appear backward?

Answer 1

Things in a mirror are not actually backward. The fact that your brain processes things as "backward" is a trick your brain plays on itself, because it thinks that the only way you could possibly be seeing the backside of an object is if you were standing inside the mirror looking out. But in reality, you see what you see only from where you are, and nowhere else... even the things you see in the mirror.

In reality, things in a mirror are reflected directly back to you, so that something that's on your left also appears on your left in the mirror. It's not backward: rather, it's exactly the way it would appear to you if you could see the backside of the object you're looking at, but without turning yourself or the object around in order to see it. How could you do that? Well, try imagining what the backside of the object would look like from where you're standing, if you could see through the object like it was semi-transparent. It would look exactly the way it looks in the mirror!

Another way to think of this is: the reason things (particularly words) look backward in a mirror, is quite simply because they have to be turned around backward (relative to where you're seeing them from) in order for the mirror to reflect them to you!

To convince yourself of this, do a very simple experiment with an object you can actually see through: Get a translucent plastic grocery bag with writing on it. Either fold or cut the bag so that by turning it over, you can see either the outside or the inside of the printed part of the bag, depending which way you have it turned.

Now, in front of a mirror, hold the bag up facing you, so that you can read the words on the outside of the bag normally. Look in the mirror without moving the bag. You can read the words in the mirror, too!

Next, turn the bag around, as though you are "showing" the outside of the bag to the mirror. When you look in the mirror, of course the words look backward, just like you expect. But now, without moving the bag, look at the bag itself. The words on the bag appear backward to you, too, exactly like they do in the mirror! They look backward literally because you turned the bag around backward. And in this case, you actually can see through the bag, to see what the bag looks like from where you're standing when you have it turned around.

Answer 2

When you look in a mirror, the reflection you see is flipped horizontally. This is because the mirror reflects light in a way that results in a reversal of the image from left to right. However, the image is not actually backward; it's just flipped horizontally.