A little science tends to lead us away from design but a lot of science tends to lead us right back?

 As Science Observes, Talk of Evolution Fades

David Coppedge

Here is something that emerges from stories that have appeared recently in journals and at science sites, including news that updates some of my previous articles. We find that the more detail that scientists observe, the less talk there is about evolution. Why would that be? Another point worthy of note: the more sophistication that is found in biological engineering, the more scientists want to imitate it. 

Jumping Robot Success

One of the most fascinating animal stories I have reported was about springtails (here). These miniature gymnasts, ranging from 2 to 6 mm long, perform Olympic-grade leaps, accelerating up to 80g, rotating at a phenomenal rate of 290 revolutions per second. Harvard reported success at mimicking the springtail with small robots that can jump 1.4 m, 23 times their length, using a rapidly unfolding furcula resembling the device the springtail uses to launch. 

Robert J. Wood’s lab had earlier reported mimicking the mantis shrimp’s club, a device that I described here. Both the springtail and mantis shrimp use “latch-mediated spring actuation, in which potential energy is stored in an elastic element … that can be deployed in milliseconds like a catapult.” Does he believe it evolved? Hard to say. The news release only says that the inspiring springtail is ubiquitous “both spatially and temporally across evolutionary scales.” That could be interpreted as stasis

Our Bubble-Wrap Noses

Feel your nose. New Scientist announced a new fact about that monument on our facial map: “Your ears and nose are made from tissue that looks like bubble wrap.” It’s a different form of cartilage from that found in other parts of the body. Maksim Plikus at UC Irvine found this by accident when studying mouse ears, lending support to Young’s Law of Science: “All great scientific discoveries are made by mistake.”

Our bubble wrap cartilage, which the UCI team calls lipocartilage due to its fat content, does not pop when squeezed, nor does it make good shipping material, but the UCI team believes that “harnessing it could make facial surgery, like nose reshaping, easier.” One item of ethical concern appeared in the article: “The team also found lipocartilage in human ear and nose samples collected from medically aborted fetuses.”

Magnetic Navigators

A sea turtle hatchling disappears into the waves. How does it know where to go? And how does it know the way back years or decades later? These questions were explored ten years ago in Illustra Media’s film Living Waters: Intelligent Design in the Oceans of the Earth. It suggested that the turtles follow magnetic waypoints in an inherited map. Now, scientists at the University of North Carolina at Chapel Hill have filled “an important gap in our knowledge” by confirming that the turtles can memorize magnetic signatures. “Through controlled experiments, the research team demonstrated that loggerhead turtles can indeed learn and remember the magnetic fields of areas where they receive food.” Incidentally, it was good to hear from Deakin University that the endangered turtles are making a comeback thanks to conservation efforts.

UNC’s discovery adds understanding about animal migration in general. “More broadly, these findings could apply to a wide range of migratory animals that rely on magnetic cues for navigation,” they said. Indeed, earlier news from the University of Oldenburg found that desert ants memorize their nest location when out on learning walks by paying attention to the polarity of the earth’s magnetic field. Changing the inclination of artificial magnetic fields had no effect, they found, but changing the azimuth made the ants aim in the wrong direction. All is not lost, however; a recent paper in Current Biology reports that desert ants use a “variety of navigational tools” in their learning walks, including path integration: “Once the learning walks are completed the ants can reach the nest from any direction.” For more on the remarkable abilities of animals to navigate by the earth’s magnetic field, see Eric Cassell’s excellent book Animal Algorithms published by Discovery Institute Press.

Zooming in on the Flagellar Stator

Calling the iconic bacterial flagella “amazing natural machines!”, news from the Nagoya Institute of Technology announced new details in the stator at unprecedented resolution. Using CryoEM (see my article here about super-resolution microscopy), Japanese scientists peered into sodium ion channels that are arranged in a ring around the stator. They determined that these channels contain “key molecular cavities for sodium ions” that “act as size-based filters that allow the intake of sodium ions — but not other ions — into the identified cavities.” This is remarkable given that some flagellar motors operate on protons, which are smaller.

As hydrated sodium ions flow through the cavities, an accompanying video explains, they generate conformational changes, “transferring the mechanical energy to the rotor to make the motor spin.” The team identified numerous specific amino acid residues in the channel involved in size filtering. Even so, “the mechanism of how the ion flux drives the rotation is still unknown,” their paper in PNAS says. As scientists around the world continue collecting detailed clues about this molecular outboard motor, it’s exciting to see them approach the secret of torque generation. And so far, as this evolution-free paper illustrates, the irreducible complexity has been growing ever since Michael Behe brought this iconic motor to our attention in 1996.

Machine Recycling

Some eukaryotes alternate between amoeboid and flagellated forms. Swiss scientists publishing in EMBO Reportsexamined one shape-shifter: “The early branching eukaryote Naegleria gruberi can transform transiently from an amoeboid life form lacking centrioles and flagella to a flagellate life form where these elements are present, followed by reversion to the amoeboid state.” When it comes time to recycle the eukaryotic flagellum (different in design from bacterial flagellum), the axonemes “fold onto the cell surface and fuse within milliseconds with the plasma membrane” (emphasis added). That’s radically fast recycling! Then, a molecular machine called spastin cuts up the axonemes into similarly sized chunks and sends them to the lysosome, where the molecules are disassembled for reuse. 

The researchers also found that the centrioles, parts of the basal bodies of the flagella on the inside, get recycled by lysosomes or proteasomes too. Some centrioles, though, are shed to the outside of the cell. “Remarkably, we discovered that externalized centrioles can be taken up by another cell,” they noted. What they found is probably not unique. “Collectively, these findings reveal fundamental mechanisms governing the elimination of essential cellular constituents in Naegleria that may operate broadly in eukaryotic systems.” Evolution made only a cameo appearance in the paper but was not essential to the science.

Cable Bacteria Update

Finally, new research on cable bacteria (see here) was published in PNAS in January. A study from the Naval Research Laboratory “presents the direct measurement of proton transport along filamentous Desulfobulbaceae, or cable bacteria. So it’s not just electrons that can travel on these miniature wires, but protons, too. And they go long distances. (Well, that is, if you consider 100 micrometers a long distance.) Why is this significant? “The observation of protonic conductivity in cable bacteria,” they say, “presents possibilities for investigating the importance of long-distance proton transport in microbial ecosystems and to potentially build biotic or biomimetic scaffolds to interface with materials via proton-mediated gateways or channels.” Proton transfer, they believe, may play essential roles in the ecology at the micro level. And as they point out, the imitation of nature in biomimetics remains a hot pursuit. Has Darwinism helped? “However, despite these hypotheses, the evolutionary benefit of this phenomenon, its role in environmental settings, and its role in microbial interaction remain unknown.” Let engineers figure it out.

Thank Darwinism for free will?

 Did Evolution Give Us Free Will?

Daniel Witt

If you pick up a book up about free will by a materialist neuroscientist, you are generally safe to assume that the point of it will be to explain that free will is merely an illusion — that we are actually at the whim of the blind forces of Nature, and are therefore not responsible for our actions. So it’s surprising and somewhat refreshing to see a self-proclaimed naturalist defend free will. That’s what Trinity College Dublin neurobiologist Kevin Mitchell sets out to do in Free Agents: How Evolution Gave Us Free Will. 

As Denyse O’Leary has noted about the book, the scientific debate over free will seems to be reviving a bit, with another book by another prominent scientist arguing the opposite position released the same year (Determined by Robert Sapolsky). So after reading Mitchell’s book, I thought it would be worth digging into the details of his argument a bit for Evolutions News readers.

Does the book succeed? By my assessment, no and yes and no. There are really several different questions at play here: Do we have a will? Is it free? Did evolution give it to us? And if so, how? Each of these subjects has its own set of scientific and philosophical difficulties, and the book is not equally persuasive on every point. To keep the various strands of the argument straight, let’s go in order, following the subtitle. We’ll start with “how evolution gave us”…  

“How Evolution Gave Us…”

Anyone expecting a defense of the claim that Darwinian processes can or did create complex neurological systems will be disappointed. That’s not the point of the book. With a very few exceptions1, Dr. Mitchell works from the tacit assumption that (a) there is no real limit to what Darwinian processes can achieve, and (b) that anything that exists in biology must have arisen through Darwinian processes. That means the book is largely concerned with describing what exists in nature, with “evolved” acting as a synonym for “is.” 

Thus, phrases like “mechanisms evolved” prevail throughout the book. Complex systems are simply “built” or “invented” or even “designed,” without much concern given to the concrete details or the relevant engineering problems. The following passage is typical:

More complex creatures emerged, colonizing and creating new niches, with expanded repertoires of possible actions. A system was then required to coordinate the movement of all the organism’s constituent parts and select among actions. Muscles evolved, along with neurons to coordinate them, initially distributed in simple nerve nets. As evolution proceeded, the nervous system became more complex, linking sensory structures to muscles via intervening layers of interneurons. The meaning of signals became disconnected from immediate action, giving rise to internal representations…   

In all fairness, Mitchell presumably did not set out to defend Darwinian evolution against other possible explanations. The heart of Free Agents is not really in explaining how we evolved to be what we are, but rather in simply describingwhat we are, according to the cutting edge of neurobiology. That’s where the book shines.

“Free”

One view of free will, called “compatibilism,” maintains that materialistic determinism and free will are really compatible. This position is apparently quite popular in philosophy of mind circles, and has been argued by Daniel Dennett and other famous philosophers. The argument says, first, that it doesn’t matter if an organism “could have done otherwise” — what matters is that the organism is the source of the action. That is, we can reasonably be said to have free will if we are able to do what we want, even if we are not able to want what we want. Second, compatibilists point out that organisms and their environments are so complex that there is no way, even theoretically, to predict what an organism will do in a future situation. So for all practical purposes, we are free. 

Mitchell finds these arguments unconvincing. They seem to be saying that if we just change our perspective, or our definitions, the problem will go away. “But I cannot escape feeling that some sleight of hand is part of this line of argument,” he writes. “It feels as if some (presumably unwitting) misdirection is going on — as if the primary problem has been circumvented or even denied, rather than confronted.” Instead, there ought to be some genuine indeterminacy in the system, or else “no matter how complex, the agent will be pushed around deterministically by its own components.” 

I think the “sleight of hand” Mitchell senses is the confusing of epistemology with ontology: confusing what can be known with what is. Regardless — Mitchell argues that the fuss is unnecessary. There is really no reason that free will needs to be compatible with strict determinism, he says, because physics, as it turns out, is not strictly deterministic. That requirement is a relic from a bygone era, when everything seemed to move inexorably according to simple Newtonian laws. Most modern quantum physicists, in contrast, agree that particles seem to actually have a degree of freedom or true randomness to their movement. So, Mitchell says, “there is nothing in the laws physics that rules out the possibility of agency or free will, a priori.” 

In fact, various studies seem to show organisms acting in a non-deterministic way. In one fascinating experiment, an electrical probe was attached directly to a leech’s central nervous system, allowing the experimenters to bypass the complexities of environment altogether and administer the exact same stimulus, repeatedly. Even under such perfectly controlled conditions, there seemed to be no way to predict how a leech (like the one pictured above) would respond to the stimulus each time. 

This apparent indeterminacy scales all the way up to more complex behaviors and situations, resulting in what is known as the Harvard Law of Animal Behavior: “Under carefully controlled experimental circumstances, an animal will behave as it damn well pleases.” 

So Far, So Good

But what about the experiments that seem to show the opposite, that free will is a mere illusion?

There are quite a few famous experiments of this kind, but in Mitchell’s professional opinion, they show nothing of the sort.

For example, Benjamin Libet’s now-famous 1983 experiment showed a signal called a “readiness potential” in the brain a fraction of a second before the subject was conscious of choosing to move his hand. Many have taken this to be definitive proof that free will is only an illusion: at the moment we think we are freely choosing, the brain has actually decided beforehand. 

Mitchell writes that this interpretation is “to put it mildly, a drastic overinterpretation”: 

That is because the design of the experiment makes it effectively irrelevant for the question of free will. The participants made an active and deliberate decision when they agreed to take part in the study and to follow the instructions of the researchers. Those instructions explicitly told them to act on a whim: “to let the urge to act appear on its own at any time without any preplanning or concentration on when to act.” They had no reason to want to move their hand more at one point than another because nothing was at stake. And so, it seems they did indeed act on a whim: they (decided to) let subconscious processes in their brains decide, by drawing on inherent random fluctuations in neural activity. 

This is what a different group of neuroscientists, led by Aaron Schurger, concluded from analyzing the data from the original experiment — that the test subjects had (instinctively, of course) set a certain potential level of neuronal activity, deciding that when random fluctuations in the brain reach that level, they would take the proscribed action. 

So now you have two plausible interpretations of the data. 

But Which One Is True? 

Another experiment, led by Uri Maoz and Liad Mudrik, sought to distinguish between the two possibilities. The researchers gave half the test subjects a decision with no serious consequences, and half a decision with consequences that they cared about. Sure enough, when the subjects were given inconsequential decision, a readiness potential preceded the decision, as in Libet’s experiments. But when the decision mattered, no readiness potential was detected. 

“Overall then,” Mitchell writes, “Libet’s experiments have very little relevance for the question of free will. They do not relate to deliberative decisions at all, where readiness potential is not observed. Instead, they confirm, first, that neural activity in the brain is not completely deterministic and, second, that organisms can choose to harness the inherent randomness to make arbitrary decisions in a timely fashion.”

So much for “free.” We’ll examine what Mitchell has to say about “will” tomorrow.

Notes

1.E.g., Mitchell mentions that the now-classic view that symbiosis might have been necessary to make the switch from prokaryotic to eukaryotic life.

Still no little green men?

 Hope for Mars Life Is Dashed Again

David Coppedge

Fifty years ago this August, the twin Viking spacecraft were launched toward Mars. They landed during the U.S. Bicentennial in 1976 at separate locations with three experiment packages designed to detect life if it existed. Two of the three yielded negative results on both landers, but one result was ambiguous. The labeled-release experiment detected unusual activity that the researchers could not explain when radioactively labeled nutrients were added to the soil. The activity gave rise to speculations that something alive in the soil was metabolizing the nutrients — speculations that, while remote, have lingered to the present day. 

Subsequent landers, beginning with Phoenix in 2008, discovered a high concentration of perchlorates in the soil. Perchlorates are chlorinated salts, often used in fireworks. These reactive salts were found to be almost ubiquitous on Mars. Now, in the journal Icarus, NASA astrobiologist Christopher McKay and two colleagues have determined that the reactions in the Viking landers can now be explained: “Perchlorate, plus abiotic oxidants, explains the Viking results and there is no requirement to postulate life on Mars.”

Profile of a zombie hunter?