(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

In the face of science advancing its frontiers of knowledge, religious believers have had difficulty clinging on to the idea that there are still Deep Mysteries for which the only solution is god. The two most recent favorites are the origin of our universe and the very beginning of life. In the series of posts on the Big Bang, we have seen that when it comes to the origins of our universe, while we have by no means answered all the questions fully, it is clear that there is nothing about it that causes scientists to throw up their hands in bafflement and proclaim that some mysterious supernatural processes are at work. There already exist perfectly natural alternatives to divine creation.

The theory of evolution by natural selection does for life what the Big Bang theory does for the universe. It explains how, once the first simple self-replicating molecule came into being, it could grow in complexity until it produced the diversity of life we see all around us. It provides a natural law-like explanation for how everything came about.

Some people cling to the hope that the emergence of the very first life form is a Deep Mystery. But at this very moment, scientists are also working on how that first self-replicating molecule was created. This question is also no longer a mystery. It has become a puzzle in chemistry for which some of the solution pieces have already been found. In his 2005 book Genesis: The scientific quest for life’s origins, Robert M. Hazen discusses the progress that has been made in this area.

So in both cases, starting with simplicity, we are well on the way to explaining how complexity in life and the universe has come about.

What becomes patently clear when we look at how the universe evolved according to the Big Bang and how life on Earth evolved according to evolution is that it all happened due to a mixture of chance and law-like behavior. In other words, there is no evidence that there was some grand underlying plan. We humans are now here but there is no reason to think that we were destined to appear in our present form.

Other alleged Deep Mysteries, such as the mind, consciousness, and morality have also long since ceased to be mysteries and instead have become puzzles for the various scientific fields on which they impinge, such as cognitive neuroscience and evolutionary biology. Scientists are working on and making progress in all these areas. (For further reading on these topics, see Moral Minds by Marc Hauser and Consciousness Explained by Daniel Dennett.) Although there is still a long way to go to answer the more difficult questions in those areas, just as in the case of the origins of the universe and life there seems to be no need to invoke any explanation that involves non-physical matter or supernatural agencies to understand these phenomena.

I want to emphasize that I am not claiming that science has answered all the important questions. Far from it. What I am saying is that scientific progress has shifted all these questions from their former status of Deep Mysteries to their new status of scientific puzzles for which we have some leads on how to investigate them. If scientific history is any guide, once a mystery has become a puzzle, it is only a matter of time before it is solved.

The increasing comprehensibility of the universe and the steady elimination of Deep Mysteries make some people acutely uncomfortable. This sense of unease, though not limited only to religious people, seems to fill religious people with such concern that they simply dismiss the possibility of total comprehensibility out of hand because it implies that this world is all there is, that there is no externally provided meaning to their lives. They have the feeling that the universe must have a purpose and plan developed by god.

In support of this position, they adopt a circular logic: They think that without a plan to give their lives meaning, there is no point to living. Since they want to live, there must be a plan and hence god must exist. And since god exists, there must be a plan because if god created the universe, why would he go to all the trouble of doing that without a plan?

Before I address the reasons why life is still worth living even in the absence of a god, I must address this curious argument and where it breaks down.

The universe does not owe us anything at all, let alone meaning. It may or may not have a meaning but the fact that some people need some external meaning for their lives does not imply that one exists, any more than the fact that some people really, really want to believe in god because of some deep emotional need means that god must exist. Whether god exists is an empirical question that one has to infer from evidence based on observation and experiment. The answer is not a given and cannot be assumed a priori, just as we cannot assume that the universe is flat simply because we may want it to be. We need data to answer empirical questions. And there is no data to support the idea that god exists.

Next: The question of meaning.

POST SCRIPT: The New War Between Science and Religion

My article with the above title has just appeared in the online edition of The Chronicle of Higher Education and should appear in the May 16, 2010 print edition.