In this clip from Genius by Stephen Hawking explore the theoretical principle called the Great Filter. The volunteers are given a contraption that will emulate the Great Filter; a theory conceived by Robin Hanson in the late 1990s that suggestions the conditions needed in the universe, in order for advanced extraterrestrial life to exist, are incredibly small. This theory is visualized in a machine; the volunteers must understand how it works. The machine has five chambers and in the first a number of ping pong balls are released. As the volunteers watch the machine they discover it is increasingly harder for the balls to move through to the other compartments. Each chamber represents a barrier to the progression of the species. The Great Filter theory suggests there may be a significant number of stumbling blocks to becoming an advanced extraterrestrial civilization. It would also suggest that advanced alien life would occur so rarely and briefly that we are unlikely to make contact.