PARTING OF THE SEAS

There was a lot of noise or static if one tried to visual the storyboards for the series. When two story lines crisscrossed they may have canceled each other out. When one character seemed to be getting his or her way, they were always brought down a peg. There seemed to be a back and forth plot tide sloshing between character backstories and the island events. Three years after there is still little clarity.

From the most basic perspective, the island was surrounded by the sea. The sea was an historic barrier to people. Technology kept human beings at the shorelines until boats were invented. But even after exploration became normal, we still do not know much about the oceans. Its breath and depth continue to be a barrier to scientific observation. The open ocean is still a vast and dangerous place. So let us assume then the setting of the LOST island surrounded by the sea. The surrounding sea is symbolic of a barrier.

So what did the barrier keep out?

If Jacob's story is true, then it would be people. The barrier kept the island hidden from public view. Only those invited to the island could see it.

Now, to explain this island barrier. The barrier could be a technology that cloaks the island from physical view (by bending light to make it appear to be open ocean). The barrier could be an dimensional barrier in a science fiction context of the space between parallel universes.

If the island is on Earth by hidden from modern man, why would that be necessary? If the island was the lost city of Atlantis it may have been hidden to keep advanced technology from modern man, who would use it against each other which would destroy the planet. If the barrier was a locked door between dimensional universes, allowing a creature to pass through could have catastrophic effects in the other universe.

The island's most valuable secret is its unique electromagnetic energy. If this is the advanced technology (how to harness it or weaponize it), that may be why Widmore wants to return and seize it to become the sole ruler of the planet. If the Light Source is life, death and rebirth, then its immortality properties could alter the balance of Earth's resources and cause massive overpopulation and the collapse of mankind into endless wars (as one predictor of the Valenzetti Equation.)

In the series, the Valenzetti Equation was a mathematical equation developed by the reclusive Princeton University mathematician. It was after the Cuban Missile Crisis to find a solution to the hostility and danger of imminent global disaster created by the Cold War. The equation was secretly commissioned through the UN Security Council and is used to predict the time of human extinction.
The Valenzetti Equation "predicts the exact number of years and months until humanity extinguishes itself."

A few of the factors included overpopulation, famine and war.

In the orientation videos, the numerical values to the core environmental and human factors of the Valenzetti Equation.DHARMA was charged with the research to change the numerical values of any one of the core factors in the equation in order to give humanity a chance to survive by, effectively, changing doomsday. However, it was determined that the scientists  failed to change the values through manipulating the environment, as the equation continues to arrive at the same six numbers.

The Light Source in effect is both the cause for and the solution to the Valenzetti problem. As such, it was too dangerous to be given to modern man to study or use.

If the island barrier was a locked portal to another dimension, what was being held back from modern Earth?  Apparently, we would have to conclude that the smoke monster. It was Flocke who told everyone that his sole mission was to escape the island. If the smoke monster got out into the real world, it would probably destroy everything in its path. So "in order to save the world" Desmond was recruited to push the button to maintain the barrier to keep the smoke monster on the island.

The smoke monster could be symbolic of many things, including Satan, the king of darkness, the evil incarnate. Or it could be a rogue variant to upset the balance on Earth by introducing chaos in everyone's daily lives. It could also be an parallel universe's disease ("the infection") which could cause madness or death if released into our universe. Dharma scientists were to study the sickness in order to find a cure so they could travel to the other universe to exploit its resources.

Any of those propositions would have given the series a sturdy story foundation from which the writers could build upon and from which the viewers could readily assess the context of the events happening to the characters. But instead of revealing what the island sea meant, we are kept in perpetual darkness.

In the theme of light and dark, dark represents death. The series did deal with the issue of life and death decisions. In fact, it desensitized death by the repetitive slaughter of characters by various means of demise (gun shot, spear, explosion, drowning, etc.) If the island was a final passageway to another dimension, it could be the after life since that is where all the island characters wound up in the end.