<P> The difference between the two is that prima facie is a term meaning there is enough evidence for there to be a case to answer, while Res ipsa loquitur means that the facts are so obvious a party does not need to explain any more . For example: "There is a prima facie case that the defendant is liable . They controlled the pump . The pump was left on and flooded the plaintiff's house . The plaintiff was away and had left the house in the control of the defendant . Res ipsa loquitur ." </P> <P> This doctrine has been subsumed by general negligence law in Canadian tort law . </P> <P> The phrase is also used in academic philosophy . Among its most notable uses is in the theory of ethics first proposed by W.D. Ross, often called the Ethic of Prima Facie Duties, as well as in epistemology, as used, for example, by Robert Audi . It is generally used in reference to an obligation . "I have a prima facie obligation to keep my promise and meet my friend" means that I am under an obligation, but this may yield to a more pressing duty . A more modern usage prefers the title pro tanto obligation: an obligation that may be later overruled by another more pressing one; it exists only pro tempore . </P> <Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2014) (Learn how and when to remove this template message) </Td> </Tr> </Table>

What is meant by a prima facie obligation
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