"… in the Logic of Scientific Discovery Popper introduces
the technical concept of a 'basic statement' or 'basic proposition,'
which he defines as a statement which can serve as a premise
in an empirical falsification and which takes the singular existential
form 'There is an X at Y .' Basic statements are important because
they can formally contradict universal statements, and accordingly
play the role of potential falsifiers."
— https://plato.stanford.edu/entries/popper/
