The Great Filter: Why We Might Be Alone in the Universe
The universe, at 13.8 billion years old, shares its age with our own Milky Way galaxy. The emergence of a civilization like ours, capable of progressing from sticks and stones to writing romantic novels and building cars and spaceships in a mere 200,000 years, is a profound milestone. Given the estimated 500 billion planets in the Milky Way alone, it seems logical to assume that numerous civilizations could have arisen before us or might emerge after us. Yet, we observe no evidence of galactic civilizations — no signs of activity, advanced technology, or interstellar communication. Space appears remarkably empty and silent.
This strange silence, despite the high chances of other advanced civilizations existing, makes us think about the Great Filter. The Great Filter is the idea that somewhere in the development from the earliest stages of life to becoming an advanced civilization, there is a significant barrier that makes it nearly impossible for species to progress beyond a certain point.
What does this mean for us? There are two possibilities: either we are incredibly lucky to have passed this Great Filter, or we are doomed to encounter it in the future. The crucial question is whether the filter is behind us or still ahead of us.
If the filter is behind us…
If the filter is behind us, we have nothing to worry about. We might be the very first civilization to reach this point, implying that something nearly impossible for other civilizations was achieved by us. What could that be? Perhaps it was the evolution from single-celled to multicellular organisms — an event so rare that it only happened once. Another possibility is the development of intelligent life capable of complex thought and communication, which may require such a unique set of circumstances that it has not occurred elsewhere in the universe.
If the filter is ahead of us…
If the filter is ahead of us, it means many advanced civilizations have already perished. This could be due to a roadblock or something truly devastating. It suggests a danger of a magnitude that has already wiped out many civilizations. One hypothesis is that advanced technology leads to self-destruction, such as nuclear wars, a genetically engineered virus, or artificial intelligence turning against its creators. It could also be something simpler, like intelligent species competing for resources until they destroy each other. Small actions can create chain reactions with unimaginable consequences, similar to how the assassination of Archduke Franz Ferdinand triggered World War I.
If the filter is ahead of us, our future could be grim. The best-case scenario for us is that we find no life on Mars or other planets, indicating that Earth-like planets are waiting to be discovered and colonized. As we think about the Great Filter, we’re faced with big questions about why we’re here and what might happen to intelligent life in space. We’re not sure if the filter is in our past or our future, as our understanding of the cosmos continues to deepen, only time will reveal the answer.
