The Great Filter

The Great Filter is a concept suggesting that there is a step or stage in the development of intelligent life that is extremely difficult to pass through. This filter could be behind us (e.g., life’s emergence or self-awareness) or ahead (e.g., advanced civilizations destroying themselves). It helps explain why we haven't found evidence of extraterrestrial life despite many planets being suitable. Essentially, the Great Filter acts as a barrier that prevents most life from reaching an advanced or detectable stage, which could be why the universe appears so silent and empty of other intelligent beings.