A solid theory, and it would make sense, but regardless of how our eyes are located or wether we have one eye or four, the behavior of the mirror remains the same, and that’s thanks to a bit of misunderstanding. We often draw intuitive conclusions from observation, and technical information is often simplified when given out as trivia or disseminated to people who have less need for detail or grounding in a field. Much of the time the distinctions aren’t relevant to “normal use,” “gravity pulls things down” would be one example- gravity pulls things towards the center point of its source, or arguably towards a focal point in curved space time. And “pulls” isn’t quite right either. 99% of people 99% of the time wont need that distinction- it generally comes to play when dealing with stellar bodies or very precise calculations of physics. For all intents we can live our lives for most of history going with “gravity pulls things down..” The same is true of mirrors!
TL:DR and the meat of the matter:
Mirrors do not “flip” images left the right. The behavior can be more closely described as mirrors “reversing” or slightly more accurately, “flipping inside” an image.
This can be best seen using transparent objects (another relative rarity in nature and human history as far as every day life), if you hold up a transparent object, features on the side of the object away from the mirror appear closer than features facing the mirror! The actual answer become more complex- but it has to do with the optics of light and how light behaves and images as we see process them works. If our eyes and brains processed images differently, we would have slightly differing perception with what we “see” in a mirror, but the behavior of the light and the mirror would remain consistent. So the mirror isn’t “flipping left to right,” but for most cases as far as most people would see and need to consider, it is generally sufficient to say it “flips from left to right..”
Post script:
Of course even a brief explanation is a bit long and might leave some confused or in doubt. A lot of detail is left out of my quick summary- so we can see the phenomenon I was speaking on earlier. To really understand the behavior of the mirror requires more in depth discussion of light and optics and more complex and somewhat obscure fundamentals that we can assume a good deal of a general audience is lacking. It is difficult to impart the relevant take aways and leave people with a working understanding without losing detail while keeping their internet and making information digestible. “Fun facts” tend to become less fun for most people when they require you to take an “intro” lecture just to understand the “fun fact.” So it is common to simplify these things but that often leads to misunderstanding when we start to discuss detail or scenarios outside of most simple everyday interactions.
To have an upside down image you'll need a concave mirror.
Mirrors do not “flip” images left the right. The behavior can be more closely described as mirrors “reversing” or slightly more accurately, “flipping inside” an image.
This can be best seen using transparent objects (another relative rarity in nature and human history as far as every day life), if you hold up a transparent object, features on the side of the object away from the mirror appear closer than features facing the mirror! The actual answer become more complex- but it has to do with the optics of light and how light behaves and images as we see process them works. If our eyes and brains processed images differently, we would have slightly differing perception with what we “see” in a mirror, but the behavior of the light and the mirror would remain consistent. So the mirror isn’t “flipping left to right,” but for most cases as far as most people would see and need to consider, it is generally sufficient to say it “flips from left to right..”
Of course even a brief explanation is a bit long and might leave some confused or in doubt. A lot of detail is left out of my quick summary- so we can see the phenomenon I was speaking on earlier. To really understand the behavior of the mirror requires more in depth discussion of light and optics and more complex and somewhat obscure fundamentals that we can assume a good deal of a general audience is lacking. It is difficult to impart the relevant take aways and leave people with a working understanding without losing detail while keeping their internet and making information digestible. “Fun facts” tend to become less fun for most people when they require you to take an “intro” lecture just to understand the “fun fact.” So it is common to simplify these things but that often leads to misunderstanding when we start to discuss detail or scenarios outside of most simple everyday interactions.