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Go to: Why smart people are stupid

gos's Avatar Jump to comment 10 by gos

From my reading, it is well established that people use "mental shortcuts" when they have to come to conclusions quickly, bypassing rational analysis.

The only examples of thought processes given in the article are these types of mental shortcuts - intuitive answers to math problems, and "overconfidence, extreme predictions, and the planning fallacy."

Is it just me, or does the article immediately move to sweeping generalizations about all thought, implying that its conclusions: "people who were aware of their own biases were not better able to overcome them"; "intelligence seems to make things worse"; and "[e]ducation also isn’t a savior"; always apply?

My own conclusion would be to emphasize the importance of careful, rational thought when considering things that matter. My intuitive conviction is that it is the only way to defeat the biases and errors that are discussed here. And I imagine that intelligence, education, and self-knowledge are all highly relevant in that type of thinking.

Thu, 14 Jun 2012 09:29:28 UTC | #947356

Go to: Church accused of 'scaremongering'

gos's Avatar Jump to comment 1 by gos

Marriage benefits society in many ways, not only by promoting mutuality and fidelity, but also by acknowledging an underlying biological complementarity which includes, for many, the possibility of procreation

The first two are beneficial to individuals and possibly to society. They, of course, are equally a part of homosexual marriage.

But explain to me again how "acknowledging an underlying biological complementarity" (the only part of this list that clearly applies to heterosexual marriage more than homosexual) benefits society...

Tue, 12 Jun 2012 13:57:25 UTC | #947052

Go to: Tree of Life Project Aims for Every Twig and Leaf

gos's Avatar Jump to comment 17 by gos

Comment 11 by Alan4discussion :

It must represent the on-going diversification including past and extinct species, as all species are "transitional species" which are continuing to evolve.

This is a non-sequitur. It is true that "all species are "transitional species" which are continuing to evolve," but it does not follow that the project being described must represent on-going diversification.

An idealised "tree of life" like that which you are describing, with all known species, both living and extinct, an extrapolated LUCA, and lots of other information which could be encoded in such a diagram, including, but not limited to: the distance from the LUCA indicating at what time the species lived, the thickness of the lines indicating genetic diversity within a "species" (up to "cristate" branch thickness), local non-treelike parts to indicate recombining species and possibly horizontal gene transfer; would be awesome (and I mean that in the sense of awe-inspiring).

However, I read the article carefully, and there isn't really anything in it to indicate that they are trying to do more than the less ambitious (but still quite ambitious) project of drawing up a tree to illustrate the relatedness of currently living species.

Wed, 06 Jun 2012 09:51:36 UTC | #945833

Go to: Tree of Life Project Aims for Every Twig and Leaf

gos's Avatar Jump to comment 14 by gos

Comment 11 by Alan4discussion :

one would be tempted to stick in any species that one has DNA for, as well as educated guesses for dinosaurs, et.al.

There is no preserved DNA beyond a certain point, so many inferences are made from fossils. Dinosaur DNA is pure Hollywood!

Yes, I know. This is why I said "any species that one has DNA for, as well as educated guesses for dinosaurs" (emphasis added).

Tue, 05 Jun 2012 18:24:30 UTC | #945731

Go to: Tree of Life Project Aims for Every Twig and Leaf

gos's Avatar Jump to comment 10 by gos

I'd like to try and answer some of the possible technical difficulties raised above as well as I can (I'm an interested layman).

It is my understanding that the project is a tree of life for all organisms currently alive, which organises them according to relative relatedness.

Comment 8 by Michael Gray :

Vis: some species split and then recombine in some way later down the track, formed a closed polygon. This cannot be visualised by a pure tree structure.

If we understand that the branches separating the end points of the tree are not intended to be illustrative of any evolutionary "path," but merely indicators of how related species are, and that we are solely dealing with species currently alive, I don't see that this is a problem. A species is either in a split state at any moment, in which case it will be represented as two end points, or it will have recombined, in which case the split will not be represented in the tree. This is not a failing unless the tree is supposed to represent extinct species as well, which I don't think that it is supposed to.

If there are past species represented in the tree as well (one would be tempted to stick in any species that one has DNA for, as well as educated guesses for dinosaurs, et.al.) then the assumption of a strict tree form would give an error for this scenario. The modern species would be shown as a descendant of one of the "split" species, and the other "split" species would shown as an evolutionary dead end. This would be an error, but it's good to keep in mind that it would be a purely local error, and have absolutely no effect on the accuracy of the rest of the tree. Such errors could thus potentially be spotted by other means than the main algorithm and corrected one by one.

Comment 9 by Alan4discussion :

Botanists for example have numerous arguments about what constitutes a genera, species, sub-species, variety or cultivar, with frequent diversity over an extended habitat range!

Isn't this really a moot point? Arguments over what should be defined as a genera/species/subspecies/etc. are arguments over where lines should be drawn between groups of organisms, not how the groups should be connected. At worst, this will lead to disagreements whether certain end points in the tree are split too fine or too coarse (so to speak), and this only happens when we demand that we use already contentious terms such as "species" for each end point, rather than agreeing that they stand for groups of organisms that are coherently genetically differentiable from other groups, and that we are only using the term "species" as a placeholder.

Then there is the feature of ring species in animals. -

End points representing ring species clearly call for a slightly different look than end points representing more "traditional" species, but this a local "bluriness" that has more to do with representation of end points than any real problem for the project. A ring species is clearly a group of organisms that is coherently genetically differentiable from other groups (i.e. they are all more closely related to one another, even the ones that can't interbreed, than they are to all other organisms).

I don't know enough about horizontal genetic exchange to comment on it. It would obviously create technical problems in using an alogrithm based on genetic difference to calculate relatedness (because you'd have to be able to differentiate between genetic material from an ancestor and material donated horizontally), but I'm curious to whether the actual "parent" of an individual is thrown into doubt.

Tue, 05 Jun 2012 14:32:35 UTC | #945693

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