Fringe has many different themes and messages that run throughout the course of the series. All of the themes tie into an overriding concept of humanity and what it means to be human. The show explores human connection and impact while examining what it means to be a human living in the 21st century.
The Progression of Science[]
One of the primary topics Fringe deals with throughout the course of its five seasons is the concept of scientific progress expanding. As Nina Sharp explains in the Pilot, "We reached the point where science and technology have advanced at such an exponential rate for so long, it may be way beyond our ability to regulate and control them." The events of The Pattern, as well as many other scientific incidents throughout the course of the series, contribute to the warning that science can pose a threat if unchecked. Another recurring idea is the borders between humanity and science. The Human Shapeshifters blur the line between "machine" and "human." The show constantly asks the question "At what point does science become more than just science?"
God[]
Many characters on the show wrestle with their faith and desire to meet/be God. In The Ghost Network, Lloyd is unsure where his abilities are coming from. He initially believes them to be messages from God but soon learns they were the result of science experiments. Walter constantly struggles with his faith. In the 1980s, Walter and William Bell wanted to become Gods, believing it was their destinies to do so. Walter even rejected the concept of God, telling Dr Warren, " There's only room for one God in this lab, and it's not yours." After breaking the fabric between universes, Walter struggles with his fear of God. He admits to Olivia that he hopes that perhaps God could forgive him for his actions. Later, Walter asks God to spare the Earth and takes responsibility for his actions.
Love[]
The concept of love is dealt with throughout the entire series. Peter and Olivia's love for each other is considered to be "destiny." Furthermore, the love the main characters share with each other is considered to be their advantage in the fight against the Observers. The heroes share a strong, binding love, while the villains (the Observers) are emotionless and incapable of feeling love.
Fate and Balance[]
It is generally understood that destiny and fate play a role in Fringe. The Observers, the villains of the show, are shown to have meddled, despite their intentions to remain neutral. This meddling has set the universes off balance, a constant conflict within the show.
Fate versus Free Will[]
A common theme usually examined through the lens of the Alternate Universe is the concept of fate versus free will and which is dominant. Characters frequently compare their lives to their alternates and wonder where the deviation occurred. Are people merely products of their environments or do individual choices account for the differences between alternate versions of the same person?
Humanity[]
The show poses the question of "What does it mean to be a human in the 21st century?" It asks how to define humanity and poses many counterexamples. The Shapeshifters are shown to be humanoid, but certainly not human. The Observers are also not considered human, although they are technically evolved, humans. The show suggests humanity lies at the root of human emotion. The Observers, who have evolved out of emotion, are thus not considered human. The show also explores the effects of choices and decisions, as well as human connection, to further study its broader themes about humanity.
Fatherhood[]
Throughout the series, there is a repeated theme of fatherhood and the extreme and destructive lengths that fathers will go to for their children.
The most prominent example of this is Walter crossing over to the alternate universe in order to save Peter, and the destruction that this action has to both universes. The heights in Walter's character development occur when Walter is able to let go of Peter for the greater good of the universe. This occurs when Walter allows Peter into the Machine that bridges the two universes. It also occurs at the end of the series when Walter is willing to travel into the future to stop the Observers, leaving Peter behind forever.
We also see that the war between the universes is spurred by Walternate's pain and anger toward Walter for kidnapping Peter. It's fitting then, that the conflict can only be stopped by his son. This finally occurs when Peter enters the machine and tells both sides that the health of each universe depends on the other.
In the alternate universe in the second timeline, Broyles is willing to become a mole, feeding information to David Robert Jones in exchange for medication that makes his son well again.
In the fifth season, Peter implants himself with the Observer tech, essentially transforming himself into an observer. He nearly loses his humanity in the process, all in an attempt to avenge his daughter's death.
Another example of this is the love that September develops for his son, the boy observer Michael. September is willing to sacrifice the existence of his race and save the humans, in part as a result of the love that he feels for his son.
The Good of One vs the Good of Many[]
There is a recurring theme of 'One vs Many', where the desire to save one person creates mass death and destruction for a large number of people. In this theme, one of the characters is required to let go of the person that they're hanging onto for the sake of the greater good.
The obvious example is that of Walter crossing over to the Alternate Universe to save Peter, causing mass destruction which only ends when Walter is able to let go of Peter.
We also see this in Alone in the World, where a psychic link is formed between a boy and a large poisonous fungus that is spreading and killing the town's citizens. Killing the fungus would mean killing the boy, and the Fringe team is nearly forced to sacrifice the boy in order to prevent more killings by the fungus. The boy is only saved when he is able to let go of his attachment to the fungus.
In And Those We've Left Behind, a man has created a time loop in order to be with his wife, before she developed dementia. But the time loop is creating adverse effects elsewhere, and he must destroy the time loop in order to prevent a mass drowning.
In the episode 6B, a woman must let go of the ghost of her dead husband (who is actually a glimpse into the other universe), in order for the fabric of the universes to stabilize.
Choices and Existentialism []
Fringe analyzes the concept of choices and our decisions affecting those in our lives. The concept of the Alternate Universe clearly shows the effects of different choices. Peter's disappearance from the timeline allows for the show to analyze the impact we have on those that we love and that love us. By removing Peter from the timeline, the show was able to see how different the lives of his loved ones would be without him, highlighting his importance to their growth and development as characters.