GRE General Test: TC-593994 GRE Text Completion

The philosopher Karl Popper held that it is not possible to conclusively prove but that it is possible to (i)_____a scientific hypothesis. His argument is founded on the basic (ii)_____underlying all inductive reasoning from which scientific principles are derived: in Popper’s words, “ The logical situation is extremely simple. No number of white swans can establish the theory that all swans are white: the first observation of a black swan can (iii)_____it. ”
Blank (i)
Blank (ii)
Blank (iii)