The continuity thesis is a methodological heuristic which underlies research into the origins of life. It posits that (i) there is no unbridgeable gap between inorganic matter and life; and (ii) the emergence of life is a highly probable process (Fry 1995). The path from non-living matter to the first living organisms is usually construed as an evolutionary process, and the conceptual machinery of Darwinian evolution (e.g., natural selection, fitness) is often used to explain prebiotic evolution in complexity. However, it is not clear whether these concepts are used in a metaphorical way, or whether they mean something different than their meaning in the context of biology. In short, it is not clear what kind of evolutionary process characterizes abiogenesis. If it is a Darwinian evolutionary process, there is a strong continuity between life and non-life: life is just an instance of a broader Darwinian process which characterizes any self-replicating and self-maintaining system. One may then question whether Darwinian evolution can ‘pick out’ life, like some definitions postulate (Joyce 1994) if it also describes non-living prebiotic processes. If the driving force of abiogenesis is a different form of evolutionary process (continuity weakly construed), then what kind, how did it get started, and how did it become 'Darwinian'?

Fry argues that the continuity thesis is required because the alternatives, creationism and the almost-miracle view (which states that life is an extremely improbable event), trump the possibility of scientifically inquiring into life’s origins. However, endorsing the continuity thesis also involves limitations and contradictions. On one hand, committing to strong continuity may take away the enigma of life’s origins, instead incentivizing focus on all complexity which results from Darwinian processes. On the other hand, committing to weak continuity still involves spotting relevant discontinuities between various kinds of evolutionary processes throughout abiogenesis in order to understand the relations between them. A challenge for the continuity thesis is: how could abiogenesis have been driven by a process of evolution by natural selection, if the conditions for natural selection to increase adaptive complexity (which include not just multiplication, variation, and heredity (Maynard Smith 1986), but also low drift and high continuity (Godfrey Smith 2009)) could have hardly been realized? If not natural selection, then what kind of evolutionary dynamics drove life’s emergence?

Thinking about the ontology of the continuity thesis is a segue to understanding fundamental questions in the field of origins of life. A comprehensive explanation of life’s origins requires understanding the type of phenomena life is and the kind of evolutionary dynamics which could have led to its initial origins and subsequent evolution.