The Archbishop of Canterbury has said that the terror attacks in Paris made him "doubt" the presence of God.
Well, good for you Justin. But why the doubts?
It's called theodicy. Here's the dilemma.
1. God is totally good.
2. God knows everything.
3. God can do anything.
4. Daesh killed 130 people in Paris.
So how come God allowed this? Hence the bishop's doubts.
There's a lot of answers that religionists go to.
1) You're wrong, there is no evil. The events of Paris weren't evil.
2) In order for there to be free will, the possibility of evil must exist.
3) The challenge of evil makes us better people.
4) Maybe this evil deed brings God's kingdom closer.
5) God works in mysterious ways, you just haven't understood why this is ultimately good.
And lots more.
I, of course, have a much simpler explanation, but if Justin Welby went with that, he'd have to resign as Archbishop. Archbishops aren't allowed to be atheists.