1. The simple falsehood at the heart of Expelled

Comment #159204 by Economist on April 11, 2008 at 4:05 pm

While accurate, the original poster's observation can and does lead to fallacious conclusions. In small populations in their early history, it is perfectly true that natural selection kills off some traits and, by implication reinforces others. But in larger, older populations many traits won't manifest until the proper pairing of parental genes. Thus counter-survival traits can be preserved and even reinforced if accompanied by pro-survival traits. Further, environment changes and what was pro-survival may become counter-survival. When the environment changes back,as it does, the older pro-survival traits might have been lost. And it is unlikely that the same traits that are pro-survival in the desert are also so during an ice age. Yet we have both desert peoples and arctic peoples who seem to trace back a long time.

When it comes to, for example, human evolution, the issue is thus far more complex than the simple--if you die your traits don't get passed on (note the omission of the word "thereafter" from the original post).

I am sure a careful probabalistic simulation might throw more light on the matter, but as a time-hardened mathematical modeller, "give me a free hand with the assumptions and I'll produce whatever result you like".

To expand on the critical earlier point, "If members of a population die or are killed off, they will leave no descendants for subsequent generations." is prima facie false. The members have to die before they produce offspring for the hypothesis (for it is that, not a logical proof as the writer seemingly would have us believe) to be correct.

Thus the only counter survival traits that produce the indicated result are those which are so counter-survival that they result in the death of the member before producing offspring. This fails to explain much that is attributed to "evolution".

And another thing..
If the original writer's reasoning were correct, shouldn't we see the extinction of many, if not most genetic diseases that invariably produce pre-puberty mortality. By now shouldn't there be none left?

2. The simple falsehood at the heart of Expelled

Comment #159198 by Economist on April 11, 2008 at 3:35 pm

While accurate, the original poster's observation can and does lead to fallacious conclusions. In small populations in their early history, it is perfectly true that natural selection kills off some traits and, by implication reinforces others. But in larger, older populations many traits won't manifest until the proper pairing of parental genes. Thus counter-survival traits can be preserved and even reinforced if accompanied by pro-survival traits. Further, environment changes and what was pro-survival may become counter-survival. When the environment changes back,as it does, the older pro-survival traits might have been lost. And it is unlikely that the same traits that are pro-survival in the desert are also so during an ice age. Yet we have both desert peoples and arctic peoples who seem to trace back a long time.

When it comes to, for example, human evolution, the issue is thus far more complex than the simple--if you die your traits don't get passed on (note the omission of the word "thereafter" from the original post).

I am sure a careful probabalistic simulation might throw more light on the matter, but as a time-hardened mathematical modeller, "give me a free hand with the assumptions and I'll produce whatever result you like".

To expand on the critical earlier point, "If members of a population die or are killed off, they will leave no descendants for subsequent generations." is prima facie false. The members have to die before they produce offspring for the hypothesis (for it is that, not a logical proof as the writer seemingly would have us believe) to be correct.

Thus the only counter survival traits that produce the indicated result are those which are so counter-survival that they result in the death of the member before producing offspring. This fails to explain much that is attributed to "evolution".

And another thing..
If the original writer's reasoning were correct, shouldn't we see the extinction of many, if not most genetic diseases that invariably produce pre-puberty mortality. By now shouldn't there be none left?