(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.

Because of the holidays and travel overseas where internet access will be sporadic, I am taking some time off from writing new posts and instead reposting some of my favorites (often edited and updated) for the benefit of those who missed them the first time around or have forgotten them. New posts will start again on Monday, January 18, 2009.)

In recent posts, I have spent considerable time discussing why I thought that belief in an afterlife and god was irrational. In the course of those posts, I described what kind of evidence I would need to convince me that I was wrong in each case. Now let me pose the counter-questions to religious believers: What kind of evidence would it take to convince you that (a) there is no afterlife and (b) there is no god?

To recap, for the afterlife, I said that a convincing evidence for the existence of the afterlife would have to consist of something incontrovertible, that simply could not be denied. Another way of saying it would be that an event must occur where an explanation that denies the existence of an afterlife is far more implausible and harder to believe than an explanation that accepts it.

Similarly, to convince me that god exists, convincing evidence for the existence of god would have to be something along the lines of the convincing evidence concerning the afterlife: god would have to appear in public to a random group of people, provide tangible proof of existence, and re-appear at a designated time and place that would allow for skeptics to be present.

I have since discovered that mathematician and philosopher Bertrand Russell, who was also an atheist, was asked the same question by Look magazine in 1953 and said something similar, that he might be convinced there was a God “if I heard a voice from the sky predicting all that was going to happen to me during the next 24 hours.”

What I am suggesting is that convincing evidence of god or an afterlife would require something along the lines that philosopher David Hume (1711-1776) argued for concerning miracles:

It is no miracle that a man, seemingly in good health, should die on a sudden: because such a kind of death, though more unusual than any other, has yet been frequently observed to happen. But it is a miracle, that a dead man should come to life; because that has never been observed in any age or country. There must, therefore, be a uniform experience against every miraculous event, otherwise the event would not merit that appellation….

The plain consequence is (and it is a general maxim worthy of our attention), ‘That no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavours to establish….’ When anyone tells me, that he saw a dead man restored to life, I immediately consider with myself, whether it be more probable, that this person should either deceive or be deceived, or that the fact, which he relates, should really have happened. I weigh the one miracle against the other; and according to the superiority, which I discover, I pronounce my decision, and always reject the greater miracle. If the falsehood of his testimony would be more miraculous, than the event which he relates; then, and not till then, can he pretend to command my belief or opinion. (my emphasis)

My point has been that proving a negative is impossible. I cannot prove that magical invisible unicorns do not live in my office but the fact that there is no evidence at all for their existence is sufficient for me to conclude that they don’t exist. The absence of such evidence for the existence of god or the afterlife is the only kind of evidence that we can have for their non-existence. So in other words, we have all the proof that we are ever going to have that god and the afterlife do not exist.

The basic argument I am making is, I hope, clear. To be convinced of the existence of god and/or an afterlife, events should occur for which explanations without god or the afterlife are far more implausible than explanations that call for them.

Clearly there are things that all of us do not believe. Presumably the adult readers of this blog definitely do not believe in Santa Claus or the Easter Bunny or the Tooth Fairy, with the same level of certainty with which I do not believe in the existence of god. They may have believed in them as children, just as they believed in god, but outgrew it in adolescence. Presumably, they do not also believe in those gods that are not in their own religious tradition.

I don’t believe in any of these things for the same reasons that I do not believe in god or the afterlife – because of the lack of any positive evidence for their reality. But why do religious believers definitely not believe in Santa Claus and the Easter Bunny and the Tooth Fairy and the gods of other religions while still believing in their own god? What is the essential difference that enables people to believe one and not the other? What evidence convinced them of one and not the others?

And back to the questions addressed to religious believers: What kind of evidence would it take to convince you that (a) there is no afterlife and (b) there is no god?

I am really curious about this because it seems like this is a central issue. I have posed these questions before in the comments discussions but never got a clear and direct answer.

POST SCRIPT: Tech support in the middle ages