Unique amongst all the Dharma Stations, The Looking Glass sits offshore on the ocean floor, elevated on a series of supports. This elevation creates capacity for a moon pool at its centre which appears to be the only access point. Curiously its logo is a white rabbit, which handily maintains a Lost motif and Alice In Wonderland vibe which is probably the most symbolic aspect of this Station to illuminate its use for Dharma.
I think we’re all agreed that the Island, for whatever reason, is a tricky place to get to. Yeah, sure, you might stumble upon it if you happen to be travelling from Sydney to L.A. on a plane that goes 1,000 miles off course and gets caught in the wrong air-space at the wrong time to coincide with an electromagnetic anomaly not being properly averted. If you manage to survive being on a plane that splits into three pieces and hurtles to the ground then, yeah, you’re there! More prudent travellers may wish to consider other means.
This is where The Looking Glass comes in. It emits a sonar ping that guides in submersible vehicles to the Island. Don't ask me how that works. The best metaphor I can conjure is of a person stumbling through a vast, dark space being guided by a single pinprick of light - without the light the person would stumble blindly interminably. Only instead of stumbling through darkness it’s more like space-time, and instead of a pinprick of light it’s more like a gateway wormhole access point. Or something. Whatever the explanation, the principle is the same: The Looking Glass’ chief function is to allow people to ‘find’ (or return to) the Island.
The big question concerns how much control Dharma exercise over this access point. Do they create the access point, or simply identify where the pre-existing access point is?
The issue of accessing the Island has perhaps been made to seem a tricky proposition due to the matter of the Oceanic 6’s return there. Compared with the relatively free comings and goings of Dharma and The Others on and off the Island, the O6 had to best replicate the conditions of Oceanic 815 on Ajira 316 after The Lamp Post identified the next location of where the Island would be. It was a lot of effort with a hit and miss result (4 passengers went back to the 70s, Sun remained in the present). But that was back when the Island was bouncing around through time. In such times The Looking Glass can be considered redundant, but generally the Island was ‘static’ and could be located via a particular bearing (like how The Freighter arrived there) or underwater by submarine.
The only reason I can see for the essential use of the submarine as opposed to a ship is to avoid the time-space discrepancy that provoked the sickness and Constant-less state that some of The Freighter crew experienced. For whatever dubious reason an underwater, unconscious approach apparently avoids this problem.
As previously mentioned, The Looking Glass logo is a white rabbit. This won't be news to the majority, I'm sure, but ‘looking glass’ and white rabbit are lifted from Lewis Carroll's Alice In Wonderland. In the book you could look through the looking glass (Victorian term for a mirror) without being seen from the other side. Maybe, just maybe, this is the fundamental raison d’etre of The Looking Glass – that a Dharma worker can ‘see’ a submarine approaching and bring it to the Island, whereas without the Dharma Station the submarine could never access the Island. This sounds like an inversion of logistical sense, but then this is 'the looking glass' that literarily leads to Wonderland where logistical sense doesn't matter a jot.
I should also mention that on the Looking Glass schematic Sayid took from The Flame the rabbit logo has a black spot with a clock face on it (pictured above). This ‘clock’ does not appear on the actual Station logo. The clock’s hands point to 8:15. Take that concept and apply as you wish but given this same schematic contained the name error of ‘Looking Glass hatch’ I’m not drawing much meaning from it.
Let’s anchor things down with more practical tidings. The Looking Glass on a day-to-day basis functioned as observation facility (probably for whatever experiments were being performed on sharks and dolphins). Desmond got his hands on a spear gun which was perhaps once a Dharma-owned spear gun that Dharma scuba divers used to capture sharks and dolphins with. There’s also an enormous cable connected to the Looking Glass on one end, and to the Island on the other (the cable that Sayid found). We don't know where or what on the Island this cable is connected to – it might be a power source controlling both sonar ping and the sonar fence, it might be a simple utility feed for power, oxygen, communications, etc, but it probably isn’t connected to The Flame since that station got blown up and The Looking Glass still seemed to function just fine. The other end of the cable remains a mystery. I can’t believe no one’s bothered to look.
The other major function of The Looking Glass besides the sonar ping is to jam (or, potentially, control) signals to and from the Island. There's a problem here in that radio waves don’t go well through water. And by “don’t go well” I mean really don’t go well. I researched it a bit and hit phrases like ‘low attenuation’ and ‘ionospheric radio wave propagation’ and figured there’s a level of information I don't need to know. Point is: radio waves and water don't mix but considering the crazy laws of science The Looking Glass already bends I’m not stressing about the matter.
Sticking with jamming outbound signals, though, raises an extremely important point. Think of the Radio Tower and the looped message playing. Before Rousseau recorded her distress call this message recited the 4 8 15 16 23 42 numbers. Dharma built the Radio Tower and set up this broadcast. So isn't it bizarre that they built a Looking Glass Station that can block signals off the Island? I mean, if you don’t want to transmit off-Island, don't build a Radio Tower! And if you do want to transmit off-Island, don't build a Looking Glass jammer! Unless, of course, one purpose of the Looking Glass is to confine the Radio Tower broadcast for the Island. . .
Why would Dharma want this equation broadcast constantly on the Island? (I am presuming here that, post-Purge, The Others took control of the Looking Glass and turned off the jammer thereby allowing the likes of Rousseau’s science team and Leonard Simms to pick up the transmission off-Island in the late 1980s.)
Let’s propose that at least one of the reasons The Dharma Initiative came to the Island was to study the Valenzetti equation. For those in the dark, the Valenzetti equation (4 8 15 16 23 42) apparently predicts the end of mankind. (This is not something really covered in the show alone, but Season 6 will apparently pick up on ‘the numbers’ so there’s foundation that this notion will come to fruition.) Dharma, in a bid to resolve the equation, begin studies. They use the Island. They isolate it from the world. They experiment. However, in order to know if their studies are effective they require some form of gauge or sign of progress. So they broadcast the numbers. The equation they hope to resolve is broadcast across the Island and, thanks to The Looking Glass, is restricted from going any further. Like how if you were studying a dangerous virus you wouldn’t want it escaping from the laboratory. On a loop, the numbers play. 4 8 15 16 23 42. Over and over.
It seems odd to think a looped message could change, but if there was some kind of fundamental breakthrough for Dharma that altered one of the values of the equation then maybe that would be reflected by the broadcast. Like litmus paper. You keep checking for alkali, but your litmus shows red for acid. You change chemicals, and keep getting red. Until, eventually, you change a chemical component that changes the litmus green and know you’ve succeeded. Maybe that same principle applies to 'the numbers' being broadcast?
Perhaps Dharma hoped for such a breakthrough. They resolve the equation. The numbers change. Or maybe they stop altogether. At that moment, The Looking Glass Station can be switched off. The Island results can be exported to the real world. The Dharma Initiative succeeded. Mankind is saved. . .
It never happened, of course (at least not in this iteration of the time loop, if there is one!) but we aren’t here to judge, merely to try and understand what Dharma were up to. They made a Looking Glass so their people could come to Wonderland but they, like us, perhaps didn’t quite appreciate how deep the rabbit hole goes.