I realize that I shouldn't be surprised at God's doing things that I can't explain. I shouldn't doubt His existence just because I find that I sometimes can't understand why or how He has made something. I know that my nature is weak and limited and that God's is limitless, incomprehensible, and infinite, and, from this, I can infer that He can do innumerable things whose reasons are unknown to me. On this ground alone, I regard the common practice of explaining things in terms of their purposes to be useless in physics: it would be foolhardy of me to think that I can discover God's purposes.