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Wednesday, December 24, 2008

Mind: We still have no explanation for why humans have minds - or thoughts

In James Randerson's "We know nothing about brain evolution" (Guardian UK, February 19, 2008) we learn that Harvard's Richrd Lewontin has pointed out the obvious:
"Why we know nothing about the evolution of cognition". He systematically dismissed every assumption about the evolution of human thought, reaching the conclusion that scientists are still completely in the dark about how natural selection prompted the massive hike in human brain size in the human line.

The main problem is the poor fossil record. Despite a handful of hominid fossils stretching back 4m years or so, we can't be sure that any of them are on the main ancestral line to us. Many or all of them could have been evolutionary side branches.

Worse, the fossils we do have are difficult to interpret. "I don't have the faintest idea what the cranial capacity [of a fossil hominid] means," Lewontin confessed. What does a particular brain size tell us about the capabilities of the animal attached to it?
Of course Lewontin is right! First, cranial capacity is not the best measure of intelligence, as brain absent humans show. While we are here, a number of studies show that some birds (notably crows) are smart - even though they do not have the brain parts we humans associate with smartness. At the time, I said,
I've long been skeptical of claims that intelligence evolved as an aid to survival. The vast majority of life forms that have survived for millions or even hundreds of millions of years did not require - or acquire - intelligence. The newer notion that intelligence is spurred by the need for complex social interactions seems a bit closer to the mark, though not entirely satisfactory. After all, many insects have achieved complex social interactions without anything like what we humans regard as intelligence.
There is no "survival of the fittest" reason why humans should be conscious! None whatever. Bacteria are way more fit than humans, but do they have thoughts? Nada. And they are probably better off without them.

So we are stuck being human and having minds, and we really can't claim that our minds give us a survival advantage. Its more the opposite. We give our minds a survival advantage.

Hat tip: Pos-Darwinista

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