Musk is more direct about extinction risk, arguing that if we become multi-planetary – settling on Mars, in particular – then a catastrophe on Earth needn"t wipe out our entire species. The SpaceX billionaire is influenced by the idea of transcending the "Great Filter", the proposal that all civilisations in the cosmos face a cut-off point in their evolution that kills them off. Musk hopes that we could be the first in the galaxy to pass that filter point.