"Gottfried Wilhelm Leibniz, a seventeenth-century German philosopher, wrote, “Nothing takes place without sufficient reason, that is . . . nothing happens without it being possible for someone who knows enough things to give a reason sufficient to determine why it is so and not otherwise.” Later Leibniz added that we often do not know these reasons. This principle of sufficient reason (PSR) flatly rejects the possibility of random or unexplainable events. Even if we are not aware of the reason behind a particular event, it is nevertheless true that there is a reason that fully explains why the event took place."
Henry Jacob – House and Philosophy Everybody Lies