And Timothy Keller has added to that conversation. First, it needs to be noted that it is virtually impossible to add anything new to this debate. Even with the birth of evolution, much of the same arguments remain valid, such as Anselm's Ontological argument.
But with the growth of atheism and secularism in our culture, it is encouraging to see a well-thought out book like Keller's, "The Reason For God: Belief In An Age of Skepticism." Keller's book is broken down into two sections.
First, Keller defends the faith by dealing with some of the most difficult issues. Some issues include the problem of suffering, hell, the exclusive claims of the gospel and Bible, the evils committed by the Church and other religious people/groups, the problem with science as it relates to faith and miracles, and many others.
Keller does not provide an exhaustive discussion on each of these issues. If he did, each chapter would take up several volumes. However, Keller deals with the issue, presenting both sides of the argument, and provides his argument. His argument is always grounded in Scripture, but at the same time, he provides arguments that aren't relying on Scripture. Keller, at times, uses secular arguments to deal with secular problems, and then points us to Scripture. I find this form of debate very effective.
If part 1 is defense, then part 2 must be offense. I like how Keller makes his argument. He begins with some arguments for the existence of God. These are all old arguments. It, again, is not an exhaustive list, but a list with some punch. I personally would use some of his arguments, or at least make them as front and center as he does. But he nonetheless is able to build his case for the existence of God on sound arguments that have been used for centuries.
And then he focuses on the issue of morality. As Christians, this is perhaps the best place to start. Keller doesn't, but it is clear that this is a major defense for Theism. Atheism and evolution cannot explain morality. Atheist and Agnostics like CS Lewis and Francis Collins began their path to faith based on this point. And it is here that Keller makes his best arguments for belief in God.
But he doesn't stop here. Keller is more than just an apologist, he is an evangelist. After developing his argument for God, Keller moves towards Christ and the gospel. My favorite discussion in this was his chapter on "the Reality of the Resurrection." Keller points out that there is no credible way to explain away the claim that Jesus died and was raised from the dead three days later.
If morality is one of the best arguments for God, the resurrection is one of the best arguments for the divinity of Christ. If Christ truly did rise from the dead, then He must be God in flesh. And if He is God in flesh, then we must take what He said seriously.
And herein lies the argument for God and the Christian message. You either accept it or reject it. But if you reject it, one must be able to counter the arguments made in this book for Keller builds his case well. But if we reject the gospel based on ignorance and laziness, then we literally will have hell to pay.
If you want to listen to some of Keller's arguments, some audio can be found here.