I finally got around to reading Carl Sagan’s The Variety of Scientific Experience, a volume edited by his wife, Ann Druyan, and based on a series of Gifford Lectures on Natural Theology that Carl delivered in 1985 at the University of Glasgow. The title of the book is a direct reference, and gentle challenge, to William James’s somewhat frustrating The Variety of Religious Experience (also based on a series of lectures, those presented at the University of Edinburgh in 1901). Although James’ text is a classic in psychology and philosophy, James drew a rather simplistic distinction between what he called “healthy minds” and “sick souls,” both analyzed in terms of empowering religious experiences. Not to mention, of course, that he sarcastically suggested to his audience of scientists that their atheism was perhaps a result of a malfunction of their liver.

At any rate, Sagan’s essays are about the relationship between science and religion from a point of view very different from that of James. At the same time, it is so refreshing to read the words of a positive atheist, which do not in the least resemble the angry and inflated rhetoric of a Christopher Hitchens or Richard Dawkins. On the contrary, Sagan’s tone is always measured and humble, and yet he delivers (metaphorically) mortal blow after mortal blow to the religious in his audience.

The science in the book is unavoidably a bit dated (though Druyan added notes here and there to update a few of the statements of fact). Then again, these essays are not about science per se, but about the meaning of science in our lives, and its conflict with the religious mind set. There are many precious passages that deserve thoughtful consideration, but one in particular struck me early on in the book (chapter 1). Sagan is talking about the sheer vastness of space: about a hundred billion stars just in our own galaxy, the Milky Way, which is one of more than 400 billion galaxies in the universe. That universe measures 46.5 billion light years across, and contains something of the order of 10 to the 80 atoms. Oh, and most of it is either empty or filled with dark stuff that is not part of galaxies, stars or planets.

After contemplating all this for a moment, Sagan says: “And this vast number of worlds, the enormous scale of the universe, in my view has been taken into account, even superficially, in virtually no religion, and especially no Western religions.” That seems exactly right, and something that is hardly discussed even in debates between atheists and theists: human religions are completely oblivious to the enormity of space. There is much talk about “intelligent design” and “anthropic principles” and other fanciful notions concocted to convince us that there is scientific evidence that this whole shebang was put in place by someone just so that we would eventually appear (and what a beautiful result he got for all his efforts!).

But Sagan’s observation makes it very clear that these people have no idea in what sort of place we really live. As Douglas Adams famously put it in The Hitchhiker’s Guide to the Galaxy: “Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space.” Indeed. What sort of intelligent engineer would create a contraption (the universe) that takes upwards of 13 billion years to generate Homo sapiens, all the while wasting 99.999999999999+ percent of the space in the universe? Or maybe, suggests Sagan, this vast amount of space and time hasn’t been wasted, and God has created many other worlds with people. But in that case, did Jesus come and die on the cross in every single one of them? Are there separate Hells and Heavens for different species of ET? The theological implications are staggering, and yet completely unaddressed.

Ah, the religious will say, but who are we to question God’s plan? He (or she, or it, as Sagan repeatedly writes) notoriously works in mysterious ways. But that is the ultimate cop out. It is simply a fancy, and frankly insulting, way to say “I haven’t the foggiest idea.” People have a right to believe whatever inane story they like to believe (as long as they do not try to impose it on others), but many religious people since Thomas Aquinas actually want to argue that their beliefs are also rational, that there is no contradiction between the book of nature and those of scripture. If so, then they need to answer Sagan’s question about why it is that the so-called holy books don’t tell us anything at all about how the universe really is.

Sagan imagines how God could have dictated his books to the ancient prophets in a way that would have certainly made an impact on us moderns. He could have said (I’m quoting Sagan directly here): “Don’t forget, Mars is a rusty place with volcanoes. ... You’ll understand this later. Trust me. ... How about, ‘Thou shalt not travel faster than light?’ ... Or ‘There are no privileged frames of reference.’ Or how about some equations? Maxwell’s laws in Egyptian hieroglyphics or ancient Chinese characters or ancient Hebrew.” Now that would be impressive, and even Dawkins would have to scratch his head at it. But no, instead we find trivial stories about local tribes, a seemingly endless series of “begats,” and a description of the world as small, young, and rather flat.

Sagan’s challenge is virtually ignored by theologians the world over. And for good reason: it is impossible to answer coherently while retaining the core of most religious traditions. The various gods people worship are simply far too small for the universe we actually inhabit, which is no surprise once we accept the rather obvious truth that it is us who made the gods in our image, not the other way around. We miss you, Carl.