It is our custom to say that someone is 'lucky' or 'unlucky' if they meet with fortunate or unfortunate circumstances, respectively. It is, however, too simplistic to think in terms of random 'luck.' Even from a scientific point of view, this is not a sufficient explanation.
The Dalai Lama (2001). “Answers: Discussions with Western Buddhists”, p.108, Shambhala
