A falsifiable hypothesis is one that can be proved or disapproved using logic or evidence. He said: “It’s based on the idea that only living systems can produce complex molecules that could not form randomly in any abundance. “This allows us to sidestep the problem of defining life – instead we focus on the complexity of the chemistry.” A vexing challenge in the search for extra-terrestrial life has been identifying which chemical signatures are unique to life, leading to several ultimately unproven claims of alien discovery. READ MORE: In a notable example, the metabolic experiments of Nasa’s Viking Martian lander on Mars found only simple molecules whose existence could be explained by incorporating “natural non-living processes” into the equation, said the research team.