How to Tell Left From Right Without a Vantage Point?
June 2, 2015 9:05 AM   Subscribe

I've encountered a few scenarios in which I've been unsure of someone's meaning when they say 'left' or 'right side.' How do you know which is which when the vantage point is not specified?

For example, instead of saying 'place your parking permit in the lower left corner of your driver's side windshield,' our notice in my building read, 'place your parking permit in the lower left corner of your windshield.' Most everyone placed their permit on the passenger side, because when they were standing outside of and facing their vehicles, that was the left side. What the building staff wanted, however, was for everyone to place their permits on the driver's side in the lower left hand corner, which is the left side of the windshield from inside of one's vehicle. Had they simply specified the vantage point, the majority of us wouldn't have had to remove and replace our permits.

I've also been confused on several occasions whilst on the phone and giving directions, and when trying to explain where it hurts on my body. When referencing sides of the body, is it always 'your' left and 'your' right, and not the left and right of the person who is facing you? It's all so confusing without a specified vantage point. Are there some unwritten rules about this or something? If not specified, is left your left and right your right from the vantage point of where you're standing/facing?
posted by Avosunspin to Science & Nature (12 answers total) 1 user marked this as a favorite
If you know theatre people, you can use stage left/right and house left/right. Stage left/right is from the perspective of an actor on the stage facing the audience -- or inside the car looking out in your example, and house left/right is from the perspective of the audience -- or from outside the car looking at the windshield. You may have some difficulty getting people to agree on what the "stage" is when you use these terms metaphorically, but it at least brings the concept to the fore and may prompt a clarifying question where a simple left/right would lead to assumptions.
posted by cubby at 9:18 AM on June 2, 2015

In medicine, it's supposed to be always the patient's right/left. This doesn't stop folks from making wrong-side errors (so it doesn't hurt to clarify when you are in such a position), but that's what the default assumption should be.

The best rule of thumb is to go from the vantage point of the user of the thing. So, if it's a car, the left hand side is the driver's side (in north america and most of the rest of the world). If you're giving directions, it's from the vantage point of the person who would be taking the directions.

Careful speakers/writers should be clarifying which vantage point they are assuming of course, but sometimes you have to guess.
posted by sparklemotion at 9:27 AM on June 2, 2015

Descriptions of medical symptoms are always from your point of view, even when the doctor is referring to it.

You: "My abdomen hurts below the stomach to the left."
Doc: "Patient reports pain in lower left quadrant."

(Regarding the sticker, this is why I wish people would use "port" and "starboard," especially when referring to vehicles. Those terms specify the vantage point, to wit, facing the front.)
posted by Johnny Wallflower at 9:29 AM on June 2, 2015 [5 favorites]

In the army on a parade there is a difference between "your left" (your actual left, whichever way you happen to be facing) and "the left", which is the parade left and stays constant. Forgetting is a great way to get yelled at.
posted by Logophiliac at 9:33 AM on June 2, 2015

Was the permit a sticker affixed to the outside of the windshield or a static cling sticker that's attached inside the window? That would be what would have affected my placement decision. If I had to be inside the car looking out to place the sticker, I would assume "left" to be driver's side. If I had to be outside the car looking in to place the sticker, I would assume "left" to be the passenger's side.

Which backs up sparklemotion's idea of going from the vantage point of the user of the thing.
posted by jaguar at 9:37 AM on June 2, 2015 [1 favorite]

Port/Starboard is already in use as Johnny Wallflower says.

Port is to the left, facing the direction the vehicle normally moves.
posted by ArgentCorvid at 9:42 AM on June 2, 2015 [1 favorite]

I don't think there's any automatic way to figure it out if you're just using the terms "left" and "right": there has to be a convention that everyone agrees upon beforehand. That's why, as others have pointed out, you have the terms "port" and "starboard" on a ship for example, always relative to the bow of the ship.

Otherwise, yeah, it seems like you'd have to either include a vantage point or some other more complicated description, involving compass directions and landmarks for example.

According to the mathematician Marvin Gardner, at first glance it appears that if we were communicating with aliens, through some method so that we and the alien civilization don't know where each other resides and can't see any common astronomical features, it would actually be impossible to communicate "left" and "right" in such a way to be certain that we're talking about the same thing (i.e. that we don't have them reversed.)

Supposedly this issue, which Gardner called the Ozma Problem, appears to only be resolved by the discovery of certain particle physics phenomena that indicate handedness in every possible environment.

Gardner wrote an entire book called The Ambidextrous Universe, in which this claim appears, about handedness, chirality, and related topics.

Wikipedia has an article entitled relative direction that talks about the same things - evidently there are some cultures that avoid using relative directions at all and only use compass/landmark directions for communicating?
posted by XMLicious at 9:46 AM on June 2, 2015 [5 favorites]

You really only know if you ask in a lot of daily interactions. Sometimes you may be lucky and pick the right direction, but thats just a coincidence in a lot of cases. For example, I would have assumed they meant driver's side, not because I knew the what perspective they meant, but all of my permits have been on the inside of a car, so I wouldn't have thought to question which left. If they wanted it on the outside I'd have been the one who goofed.

For medical issues, Left/right will be the patients' left/right: the patient's perspective if fixed. But you can always clarify: my right ear hurts (and point if you're in person).

Clarify when you think of it, but if a mistake is made, just correct it and move on. It happens a lot, and I think most people just don't notice and/or get used to each others idiosyncratic ways of doing things. If someone is being grumpy about you not understanding their vague directions, make sympathetic noises but don't engage (they'd likely be grumpy about something else).

When you give directions/instructions, try to specify your/my right as appropriate. I try to give directions based on their vantage point when I can (move the chair two inches to your left, or better yet, specify toward the wall). When you're directing someone to your house, you likely know their orientation already, so just give it based off of that. If people mess up, again just correct and move on.
posted by ghost phoneme at 9:46 AM on June 2, 2015

Bah—the mathematician I mention above is actually Martin Gardner. Just missed the edit window...
posted by XMLicious at 9:55 AM on June 2, 2015 [3 favorites]

For the car, I'd have specified driver's side or passenger side, and skipped left/right on purpose, to avoid just this kind of confusion: driver's side/passenger side is clear to all, no matter what angle they're looking to or from.

For medical stuff, I'd go with a specific "the pain is in my left/right side", again to avoid a question of doctor's or patient's viewpoints.

For giving directions, once again I'd specify: "the mall will be on your left/right".

But I'm an old Navy brat, and I also use port/starboard where I think I can get away with it....
posted by easily confused at 10:27 AM on June 2, 2015

For skiing/snowboarding there are two different ways of describing directions. If you intend the directions to be used by someone actively descending the mountain you'd say "Skier's/Boarder's Left or Right". If you are at the bottom of the mountain looking up, you'd describe things as "Looker's Left or Right".

As for generalizing this advice you should heel a modified version of Postel's Law in such that you should attempt to be as unambiguous as possible when giving directions and try to make a sensible guess of what a direction giver intended and failing that, ask for for clarification.
posted by mmascolino at 12:56 PM on June 2, 2015

Best answer: There is a set of terms in English for this which is, unfortunately, now somewhat archaic, but deserves to make a comeback.

Proper Right
posted by Miko at 5:25 PM on June 2, 2015 [2 favorites]

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