Karl R. Popper in Logik der Forschung , advanced
the theory that the test of an empirical system, the demarcation
of the limit of scientific knowledge, is its 'falsifiability'
and not its 'verifiability,' his aim being "to select the
one which is by comparison the fittest, by exposing them all to
the fiercest struggle for survival". To be falsifiable systems
of statements must be logically precise and unambiguous, i.e.,
capable of being "subjected to tests which might result in
their refutation".