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Friday, 13 May 2016

On science and metaphysics

One Long Argument -- Responding to VJ Torley on Human-Ape Common Descent
Cornelius Hunter 

At Uncommon Descent, VJ Torley has analyzed my criticism of S. Joshua Swamidass's recent article, "Evidence and Evolution." From this analysis, one would think that I mercilessly berated a poor fellow who was merely attempting to "extend an olive branch to creationists." After all, nowhere did Swamidass belittle or ridicule his opponents, and nowhere was there so much as a trace of smug superiority. And the guy is a Christian, not some atheistic reductionist. In fact, Swamidass does not even draw any conclusions in his article.

This is how Torley begins his article and unfortunately it gives those who have not read the two articles the wrong impression. I gave a lengthy, fact-based, scientific criticism of Swamidass's claims that was not dismissive or sarcastic. I did not accuse of Swamidass of belittling or ridiculing anyone, nor did I accuse him of smugness, academic or otherwise. And I did not question his religious beliefs. All of this was injected by Torley.

As for drawing conclusions, yes, contrary to what Torley says, Swamidass draws conclusions. He states in no uncertain terms that the evolutionary story "is by far the best scientific explanation of our origins." In fact, the evidence is stunning:

What is the evidence for human common ancestry with apes? The strongest evidence is a series of stunningly accurate predictions about human genomes that have been confirmed in recent decades as the human and ape genomes have been sequenced.
Swamidass goes on to suggest that microevolution is sufficient to explain the evolution of humans from a small, ape-like creature.

Throughout, Swamidass uses a scientist-versus-theologian, Warfare Thesis perspective. Scientists simply refer to the data whereas theologians must adjust their sights, drop their denial, and grapple with the undeniable truths of evolution. To object is futile and attempts to explain humans as a product of design are "lawyerly":

A common lawyerly objection to this evidence is that these similarities are "equally" explained by common "design." As scientists, our response to this objection is data.
Perhaps the theologian "could look for errors in the scientific analyses," but even that would be futile:

Still, even if he [the theologian] found standing for quibbles here and there, the overall picture would remain the same and the evidence against common ancestry, at best, would be subtle and debatable.
Swamidass presents a story in order to "reduce the fear some feel when encountering evidence that might contradict their understanding of the Bible."

This is all Warfare Thesis, and Torley finds it to be "irenic in tone, easy to follow, deeply learned, and absolutely right."

On the other hand Torley throws occasional ad hominems my way and finds that my critique of Swamidass's piece was "polemical and curtly dismissive in tone." In fact, my criticism was about Swamidass's arguments. I pointed out that his scientific claims were erroneous and that ultimately his arguments relied on metaphysical claims.

This is not to say there cannot be improvements in my article. It is, after all, a blog post. I'm thankful for feedback and corrections to my errors. But Torley's casting of the two articles is simply a misrepresentation. It seems that his criticism of my post is, in fact, more applicable to his article.

What About the Science?

Torley next castigates me for ignoring the main scientific evidence Swamidass presents. And what is Torley referring to? A series of references Swamidass made. So instead of addressing the key scientific claims made by Swamidass (which I did), I am supposed to do an expansive analysis on several references Swamidass provided as backup.

In fact I was planning on getting to those references at some point, time permitting, as they are yet more examples of failed science. But Torley's requirements and criticisms are unrealistic.

Torley next quotes from one of Swamidass's references, imagines what my response would be, and argues with it. This is getting silly.

Torley finishes with a series of erroneous rebuttals, ad hominems, and straw-man arguments. To be sure, Torley makes some good tangential points, but they are unfortunately the minority.

Not surprisingly Torley shares Swamidass's theological convictions, which underwrite their claims. Their contrastive reasoning, if correct, proves their case. As Torley writes:

On a special creationist account of human origins, there is absolutely no reason to expect that humans would have what appear to be the remains of genes used for making egg yolks in their DNA -- just as there is no particular reason to expect that humans would be more genetically similar to chimps than rats are to mice -- or for that matter, than foxes are to wolves, or horses are to donkeys. [Emphasis in original.]
No reason. If Torley is correct here then, yes, we can safely conclude for evolution. Likewise:

Reasoning on Bayesian grounds, these striking and singular facts have a high probability on the hypothesis of common descent, but are surprising (and hence improbable) on a hypothesis of separate creation. One can only conclude that these facts lend scientific support to the hypothesis of common descent.
True enough. Such reasoning is perfectly valid, but it hinges on metaphysical premises. From a scientific perspective, evolution and common descent are unlikely to say the least, but from a metaphysical perspective, they are compelling.


Religion drives science, and it matters.

How the case for design is as plain as the nose on your face

Smelling Design
Evolution News & Views

How's this for an admission that design principles motivate scientific progress?

For an engineer, successful design of a new product needs to meet multiple objectives such as maximizing targeted mechanical performance and minimizing the cost. Some of these objectives are incompatible, thus tradeoffs are necessary. Similarly, living organisms are also constantly ... optimizing multiple objectives such as growth rate and resistance to environmental fluctuations. A central task for systems biology is to unravel the corresponding mechanisms, or the design principles ultimately determined..., especially how a system prioritizes the multiple objectives and makes necessary compromises.
That's a great quote except for the parts we left out. In the first ellipsis, the authors of a paper in PNAS insert these words: "[are also constantly] under selection pressure to maximize their fitness to the environment through [optimizing]..." The second ellipsis adds, "by evolution." But since engineers are neither under the pressure of natural selection nor working by blind chance, the extraneous words destroy the comparison, and thereby contribute nothing to the meaning.

The paper deals with an interesting problem in biology. Our noses contain millions of olfactory sensory neurons (OSNs). Each neuron expresses one and only one type of olfactory receptor (OR, a molecular machine that recognizes a particular odor molecule). There are hundreds, in some animals thousands, of different receptor types. How does each receptor get its fair share in the distribution? It's "one of the most intriguing problems in neurobiology," the authors say; "how can both monoallelic and diverse expression of OR be ensured at the same time?"

The answer "remains elusive after several decades of intensive investigations" -- until one thinks like an engineer. At a key point in the paper, despite other attestations about evolution, they make their breakthrough with these words: "Then from an engineering perspective, a better design to achieve single-allele activation is..." and so forth [emphasis added]. The body hits the optimization target successfully just like a good engineer. Actually, it does it better. Their simple model, flowchart and all, is less sophisticated than the nose itself.

The final paragraph nicely states the centrality of design principles in their research (and says nothing more about evolution):

In summary, we have constructed and analyzed a comprehensive model that revealed a mechanism for achieving diverse and monoallelic OR gene expression. A proper combination of mechanisms, but none of the individual one, can achieve the desired diverse and monoallelic OR expression. Given that multiobjective optimization is ubiquitous in biological systems, this synergetic and sequential application of different mechanisms is likely to be a general design principle on biological process regulation, and shed light on problems in other fields as well. This work aims at using a minimal model to reveal the essential elements that regulate the OR selection process. For example, [four examples given].... Future studies will reveal these possible fine-tuning elements and address its implications in other processes of gene regulations.
A statement from the University of Pittsburgh about this paper doesn't mention design or evolution, but summarizes the principle finding as "a basic physics principle called cooperativity, in which elements in a system influence the behavior of one another rather than function independently." The synergy between neurons the scientists witnessed gave them the chills. "We are amazed that nature has solved the seemingly daunting engineering process of olfactory receptor expression in such a simple way," one said.

Designed Winnowing

Another paper, this one in Current Biology, addresses the same problem from another angle. "A genetic approach in mice reveals a new facet of odorant receptor (OR) regulation," the summary begins. "Adventitious expression of multiple ORs activates post-selection refinement (PSR)." As the neurons sort themselves out in the olfactory epithelium during development, failures occur. Some neurons, contrary to the rules, express more than one receptor. Don't worry; a cleanup crew is on hand to take care of them:

Here we used a genetic approach in mice to reveal a new facet of OR regulation that corrects adventitious activation of multiple OR alleles, restoring monogenic OR expression and unique neuronal identity. Using the tetM71tg model system, in which the M71 OR is expressed in >95% of mature OSNs and potently suppresses the expression of the endogenous OR repertoire, we provide clear evidence of a post-selection refinement (PSR) process that winnows down the number of ORs. We further demonstrate that PSR efficiency is linked to OR expression level, suggesting an underlying competitive process and shedding light on OR gene switching and the fundamental mechanism of singular OR choice.
This paper had no use for Darwinian theory. The "selection" they speak of is not natural selection, but rather the initial choice of OR that each OSN expresses. How could a blind process know that expressing multiple ORs on the same neuron is a problem? How could it know what needs to be winnowed down? The paper calls this "Cleaning Up After Feedback." It sounds designed. "The process we describe here may represent a 'failsafe' mechanism," they say, when the normal process doesn't generate a single outcome like it's supposed to (e.g., one OR per neuron). Their summary explains why that might happen, and how the body is prepared to deal with it:

OR regulation generates >2,000 transcriptional outcomes, endowing an equal number of OSN identities. This extreme selectivity results from a slow initial phase, when individual OR alleles are infrequently activated, followed by a feedback stage halting the process and preserving singular choice. Mathematical modeling has determined parameters for activation and feedback that ensure a high probability of singular expression. These analyses also defined a failure rate, when activation proceeds too quickly, or feedback proceeds too slowly, resulting in neurons expressing multiple ORs. OSNs are unlikely to use feedback suppression to restore singular OR expression once more than one allele is activated. We have revealed a post-selection refinement (PSR) mechanism, which restores singular OR expression and unique neuronal identity.
This is a nice supplement to a previous article here on olfaction two months ago, where we learned how individual olfactory receptors (ORs) respond to not only the shape but vibrational energies of odor molecules, and then took a look down the line at the olfactory bulb to see how the switchboard maintains its complex wiring. Those were design features of the operational adult nose. Now, we see that the design principles of optimization, feedback, and refinement are at work in the initial setup stages of the neurons and their receptors. "From an engineering perspective," it's clearly design all the way down.

But Wait, There's More

Yes, another recent paper shows a nose for "design principles" without mentioning evolution. This paper from Harvard, published in PNAS, uses the phrase "design principle" three times. The authors wanted to understand how a relatively small number of receptors can produce so many scent sensations. Humans only have about 300 ORs but can discriminate at least 2,100 odorant molecules. Other animals, like dogs, have much higher sensitivity. How is this possible? It's by design. "Such remarkable molecular discrimination is thought to use a combinatorial code," we know from earlier studies. Once again, we find optimization (an intelligent design science) at work. The receptor arrays are optimized for natural odor statistics, these scientists discovered:

We study a simple model of the olfactory receptors from which we derive design principles for optimally communicating odor information in a given natural environment. We use these results to discuss biological olfactory systems, and we propose how they can be used to improve artificial sensor arrays.
There you have it. Not only do the authors finding design principles useful for understanding the nose, they look forward to how to copy those principles for artificial noses. The optimization, by the way, continues all the way to the brain:

The activity of a single glomerulus is thus the total signal of the associated receptor type, so the information about the odor is encoded in the activity pattern of the glomeruli. This activity pattern is interpreted by the brain to learn about the composition and the concentration of the inhaled odor. We here study how receptor arrays can maximize the transmitted information.
Using an "information theoretic approach" to quantify how well a receptor array matches the odor statistics in the environment, they even make predictions:

Using an information theoretic model, we show that a receptor array is optimal for this task if it achieves two possibly conflicting goals: (i) Each receptor should respond to half of all odors and (ii) the response of different receptors should be uncorrelated when averaged over odors presented with natural statistics. We use these design principles to predict statistics of the affinities between receptors and odorant molecules for a broad class of odor statistics. We also show that optimal receptor arrays can be tuned to either resolve concentrations well or distinguish mixtures reliably. Finally, we use our results to predict properties of experimentally measured receptor arrays.

Naturally, biological noses, whether in humans or fruit flies, with their "remarkable molecular discrimination" abilities, vastly outperform the sensitivities of "artificial nose" devices created so far. Codes -- optimization -- information: design principles are propelling research into the secrets inside your nostrils.

Thursday, 12 May 2016

Epistemology vs. Darwin.

Evolution May Obscure Reality, Says a Cognitive Scientist and Evolutionist


Wednesday, 11 May 2016

Genetic evidence for common ancestry?Or give us a miracle and we'll explain the rest.

Stunning Evidence for Common Ancestry? S. Joshua Swamidass on the Chimp-Human Divergence


As 'Just so' as it gets II

Rafting Monkeys "Fill a Gap" in Evolutionary Theory?


Tuesday, 10 May 2016

Darwinism vs. the real world XXIX

Calcium's Role in the Body -- and a Note on the Origin of This Series



Monday, 9 May 2016

Twenty years later and proto-life is more irreducibly complex than ever

Galloping Flagella and Cilia Railroads -- Getting Ready to Celebrate Twenty Years of Darwin's Black Box