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Tuesday, July 08, 2008

Common descent and uncommon descent - answer to a reader's question

A reader of The Spiritual Brain asks,
... , you write that evolution (i.e., macro-evolution, descent by a common ancestor) is a fact, given the fossil record. Do you really believe this, or this is simply a concession to the scientific establishment, in other words, a disclaimer of sorts that is making sure that your ideas in this book can be taken seriously ...

Well that was grounds for a gourmet cup of coffee!

The Spiritual Brain was an enormous amount of work. Mario and I risked much to maintain what we think the evidence supports about the non-material nature of the human mind.

Anyone who thinks we would complicate our lives by also maintaining positions we do not support ... has a future in writing afternoon soaps, where life is the art of the impossible.

So I wrote back and said,
I am intrigued by the way you put your question, “Do you really believe this?”

It reminds me of the day I was received into the Catholic Church (as an adult).

But I am not sure that a question about common descent should remind me of my reception into the Church. Let me explain why:

I do not have either an emotional or intellectual problem with the idea of common descent of all living things.

As an idea, common descent is very convenient. I would like to think that all the information needed for the universe to unfold was encoded at the Big Bang.

However, convenience does not make an idea accurate to reality. What I would like to think might not be true. The true story might be messy. It might be something I will never know, and I must live with that.

There is evidence for common descent, but the so-called tree of life is such a mess now that I would be more inclined to think of it as the Lego (c) set of life. (Don’t like it this way? Organize it that way then!)

Here is the difficulty: If common descent remains a central idea but the details often collapse in the telling, it may come to be held as a sort of “religious” position.

And that is how it often is held. As I explained in a recent book review, "… this new religious profession [of common descent] helps us understand many peculiar current obsessions of the pop science media - like trying to prove that great apes think like humans, for example.

One must ask, why would it matter so much if great apes don't think like humans? That would not be a blow to common descent of humans and apes because no one maintains that common descent requires detailed similarity or even, for that matter, that similarity is strong evidence of descent.

After all, ravens may also think like humans in certain respects, and no one proposes reorganizing our current ideas about common descent on their account.

It would be closer to the mark to say that seeking such similarities is a religious exercise among those for whom common descent is not so much a convenient explanation of origins as an article of religious faith. "

In other words, in the case of humans and chimpanzees, genetic similarities such as the vitamin C pseudogene and physical similarities are strong evidence for common descent, but similarity of behaviour or mental capacity are not.

That is why I say that obsessive pursuit of such similarities “so that we can learn about ourselves” reveals an underlying tendency among some in our society to treat common descent as a sort of religious truth – and sometimes as a crusade.

Mario and I both think that the non-material nature of the mind is easily demonstrated. If the current science establishment has difficulty accommodating that, so much the worse for the establishment. People who refuse to take us seriously will eventually have to take the evidence seriously, and we are patient people. Cheers, Denyse


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