Mika cut her foot last night on a piece of broken glass that was in her kitchen. She tells you that her flatmate doesn't like her and because she had a big party that night, her flatmate had put the glass in a place where only Mika would step on it and hurt herself. She is convinced that her flat mate had planned this for weeks just to upset her. You suggest that maybe it was just some random glass from a bottle that broke. 

Which of the principles of science does Mika's explanation violate?