Tuesday 18 July 2023
Go to the ant and be instructed?
Ants Build Landmarks for Navigation
Picture being alone on a featureless planet. You’ve just left your underground station and are seeking minerals necessary to supply the base. Soon, the station entrance vanishes from sight as you continue searching. When you find the minerals, you turn around and have forgotten the way home! The horizon all around you is a monotonous waste. You wish you had left breadcrumbs like Hansel and Gretel, or better yet, had built a tall visible tower where the base is.
This is the plight faced by Cataglyphis fortis ants that live on a salt pan in Tunisia. Tree ants and rock ants do not have this problem; they have plenty of landmarks. But the ones that live on the salt pan are surrounded by a white, flat horizon in all directions. Along the shoreline there are visual cues, but those out in the middle of the playa have few to none. The ants face death from heat exhaustion as they forage under the hot sun alone, walking fast to keep their feet from overheating. Scientists from Germany were intrigued how they can almost always navigate their way back to the nest.
Eric Cassell discussed ant navigation in Animal Algorithms, noting that with brains only a quarter the size of a honeybee brain, ants “produce exquisitely efficient, robust navigation in complex environments” with their 250,000 neurons. As mentioned for the salt pan, simple environments without landmarks can be no less challenging. The situation calls for exceptional methods of path integration, especially for solitary foragers like C. fortis. For path integration to work, the ants need a neural compass and neural odometer and memory to store the global vector, Cassell says. The global vector can also be informed by odor trails, a polarized light compass and sun compass, and by landmarks.
Landmark Foresight
The successful strategy of C. fortis ants was revisited recently in Current Biology by Freire, Bollig, and Knaden. Their observations and experiments showed that the ants build landmarks on the journey out — but only when needed. Commenting on the research in the same issue, Cornelia Buehlmann rhapsodized about the architectural abilities of ants and many other creatures.
When we look at structures built by animals, we instantly appreciate that animals are naturally better architects than most humans. For example, beavers build fascinating constructions containing dams and dome-shaped lodges; birds construct elaborated nests; badgers form setts consisting of extensive underground networks of tunnels and chambers; termites build enormous mounds that can be a few metres in height; and ants build amazingly complex nest structures in many sizes and shapes. The key purpose of most homes is to provide a safe shelter for its inhabitants. Animals need to be safe from harsh weather conditions, hide from prey or house their offspring. Most animals have optimised the way of building their homes to get the best possible protection. Termites and ants, for example, have the ability to build nest mounds that allow perfect thermoregulation and ventilation and also protect from occasional flooding. Of course, nest structures can also have other functions: bird nests, for example, can play a role in sexual selection. A new study reported in this issue of Current Biology by Freire et al. now shows that nest hills from desert ant colonies not only provide a safe home but that they are built as visual landmarks and are crucial for successful navigation.
The height of the nest hill is one strategy used by C. fortis ants for navigation. The entrance hill can be up to 10 cm high, visible tens of meters away. Some foraging ants, though, travel up to 1 km away, beyond line-of-sight visibility. This new measurement, longer than previously recorded for this species, shows that ants must be able to use multiple cues for path integration.
Experimental Setup
To see if the ants use their tall nest hills for navigation, the research team removed 16 nest hills at sites deep in the salt pan too far out for visual cues from the shoreline. They placed cookie crumbs at various distances to tempt foragers to venture out. Adjacent to half of the nest entrances, they placed 50-cm black cylinders as artificial landmarks, then followed individual foraging ants at a safe distance. They found that the ants were able to use the artificial landmarks to get back, but navigation was impaired without the cylinders. At those sites, they observed the ants inside the colony busily rebuilding their nest hills. This proved that the height of the nest hill is important as a visual landmark, not just for flood protection or thermoregulation. Buehlmann comments,
These results show that ants are less likely to build these hills when other landmarks are available. This is a fascinating finding that suggests that ants sensibly decide whether it is necessary to build a nest hillthat facilitates the accurate localisation of the nest entrance.
To Buehlmann, this implies that “Small-brained animals have the cognitive ability to control the colonies’ navigational success.” As a result, fewer individuals die of heat exhaustion or are killed by a predator.
Foraging in the salt pan is a race against time. About 20 percent of the foraging ants that were displaced by the researchers died in the desert sun while trying to find their way back. Other arthropods routinely die in the heat, too, providing a main source of food for the C. fortis ants. The cookie crumbs were undoubtedly a treat. One ant got as far as 2 km out but didn’t make it back. The record for distance and successful return with its cookie crumb was 1.1 km — probably near the limit of its physical ability. So far from its visual cue, it must have relied on other cues to successfully integrate its path back home.
Investment Wisdom and Information Flow
The importance of having a tall nest was a surprise to the research team:
We were surprised that Cataglyphis ants not only build their own nest-associated landmarks but also do so readily when deprived of other visual cues necessary for navigation. A colony’s investment into building a nest hill is justified when other guiding visual cues are absent, as fast and efficient homing is evidently paramount for survival in the harsh habitat of the salt pan. However, as soon as other visual cues are present, the investment does not seem justified anymore and no nest hill is rebuilt.
The whole colony must be involved in the investment of having a tall landmark.
Foraging is usually the last task in the life of a Cataglyphis worker, while the digging involved in building the nest hill is often performed by younger ants. This calls for some kind of information flow between the older foraging ants that face the lack of visual cues surrounding the nest and their younger nestmates responsible for building the nest-defining landmark.
How Do They Know?
If the younger ants do the work of rebuilding the nest hill, Buehlmann wonders how they know to get to work on the project.
If so, how do they know whether there is a lack of nest-defining cues around the nest? At the start of an ant’s foraging career, ants do well-choreographed learning walks around the nest. Their general purpose is the acquisition of information about the visual surrounds of the nest with relation to celestial compass cues. Future experiments will need to reveal the mechanisms of the described nest building behaviour and show who is triggering the hill re-building. It will be exciting to learn how individual foraging and navigation relates to colony-level nest building activities and if and how information is shared between nestmates about the need to build a nest hill for navigational purposes.
Beyond Machinery
In this extreme case of life-or-death navigaton, the ants show themselves remarkably well equipped. They are born into the world with sensors, algorithms, and integrated systems of moving parts supplied by nutrients and machines that enable them to walk fast under the hot sun and perform sophisticated navigation. But more is required.
Of interest in the context of the design debate, information flow is once again shown to be central to the story. Having neurons packed into a tiny brain is important, but neurons are useless without information. Information is an intangible, nonphysical, conceptual reality that makes life work. Information is the substrate on which life operates, and wisdom is the effective use of information. It can be programmed into code, but wisdom is the bequest of a beneficent and capable mind.
On the metaphysics of science?
Can Science Escape Faith-Based Beliefs? Maybe It Needs Them!
Physicist and astronomer Marcelo Glieser offered some thoughts recently on faith and science, noting that the scientific revolution has hardly changed the picture of faith much: “the great scientific advances of the past four centuries have not radically diminished the number of believers” in transcendent realities
If science is to help us, in the words of the late Carl Sagan, by providing a “candle in the dark,” it will have to be seen in a new light. The first step in this direction is to admit that science has fundamental limitations as a way of knowing, and that it is not the only method of approaching the unattainable truth about reality. Science should be seen as the practice of fallible humans, not demigods. We should confess our confusion and acknowledge our sense of being lost as we confront a Universe that seems to grow more mysterious the more we study it. We should be humble in our claims, knowing how often we must correct them. We should, of course, share the joy of discovery, the achievements of human inventiveness, and the importance of doubt.
MARCELO GLEISER, “FAITH-BASED BELIEFS ARE INESCAPABLE IN SCIENCE,” BIG THINK, JUNE 28, 2023
As he implies, there’s no reason why it should. Science, for better or worse, is a faith-based enterprise. Along with many easier quests, scientists continue to pursue outliers like the origin of life, whether there is life in remote star systems, and the nature of consciousness. Many such topics border on metaphysics and may well involve imponderables. But then finding the right answer might not be as important in some cases as developing the right questions.
Why must scientists have faith that we can make progress in understanding our world? Political analyst M. Anthony Mills proposes at least three general ideas about what science does. What we expect science to do for us largely depends on which one of them we adhere to.
First Model
The first is what we might call the accumulationist model of scientific progress. According to this model, science progresses through the steady accumulation of data, facts, or information. The guiding metaphor here is the container: scientists go out and find bits of knowledge and add them to the container. Scientific progress is therefore a cumulative process, linear and gradual.
M. ANTHONY MILLS, “WHAT DOES ‘SCIENTIFIC PROGRESS’ MEAN, ANYWAY?” THE NEW ATLANTIS, SPRING 2023
This model is popular but it can lead us astray. “Science will find the answer!” is only meaningful if the question is framed in a way that science can address. Science can’t tell us whether we are our brother’s keeper, whether it profits us to gain the whole world if we lose our souls, or whether some unfortunate person’s life is worth living. Unfortunately, science is sometimes misused to add apparent weight to a given answer, when the question is really one of ultimate spiritual values, not of science.
Second Model
Another model is what Mills calls “Kuhnian,” after the famous philosopher of science Thomas Kuhn (1922–1996), who introduced the concept of paradigm shifts in science:
According to this account, progress is not linear and gradual; it is punctuated by moments of profound conceptual change and innovation. There are periods of relative calm — what Kuhn termed “normal” science — during which progress looks a lot like it does to the accumulationist. But these periods are interrupted by crises, when prevailing theories break down. Rivals emerge, challenge the consensus, ultimately overthrow a prevailing paradigm, and take its place, as when relativistic and quantum physics dethroned classical physics. These are the scientific revolutions that Kuhn called “paradigm shifts.”
M. ANTHONY MILLS, “WHAT DOES “SCIENTIFIC PROGRESS” MEAN, ANYWAY?” THE NEW ATLANTIS, SPRING 2023
When we are contemplating a vast historical sweep, Kuhn’s theories are indeed helpful. But on the ground, we usually can’t know for sure whether we are living in a massive paradigm shift. Theories rise and fall all the time. Which of the changes matter? For example, findings from the James Webb Space Telescope upended a variety of assumptions but how much they will change the basic paradigm remains to be seen.
Third Model
He calls the third model Baconian, after the early modern philosopher of science Francis Bacon (1561–1626):
According to the third model, however, science progresses not by extending existing scientific paradigms, nor by resolving problems or crises internal to science. Instead, science progresses by grappling with problems posed to it from outside by social, political, and economic needs. We recognize scientific progress not by advances or innovations in our theoretical knowledge but by whether and to what extent our theories help us solve practical problems. Does science generate technological breakthroughs, contribute to economic growth, or help us solve pressing social and political problems?
M. ANTHONY MILLS, “WHAT DOES “SCIENTIFIC PROGRESS” MEAN, ANYWAY?” THE NEW ATLANTIS, SPRING 2023
Of course, if we rely entirely on the third model, we might reject science that isn’t telling us what we want to hear, even if what it is telling us is true and important.
Generally, as Mills acknowledges, we must try all three models to see how much each can contribute to our understanding. But each model requires an initial input of faith: Faith that a big picture will emerge from small contributions (Model 1), faith that we will recognize when theories must change (Model 2), and faith in a bigger picture of the universe that we don’t allow our current issues to completely obscure (Model 3).
No matter how scientists navigate between models, Gleiser thinks that, for creativity in science, faith is indispensable:
A scientist therefore must base their approach on an imponderable process that some call a hunch or an intuition. This is an intellectually guided expression of faith in how the scientist imagines the world to be. There is no way to venture into the unknown without this guiding light, and that light comes from a source that is not completely known. This is where science meets faith.
MARCELO GLEISER, “FAITH-BASED BELIEFS ARE INESCAPABLE IN SCIENCE,” BIG THINK, JUNE 28, 2023
It’s hard to imagine creativity in science working any other way.
Finding context for the sophistication of primeval technology
Something Is Missing from the Materialist Framework
In sketching here what I have called the science of purpose, I have argued that the best way to topple the materialist paradigm is to reverse the fundamental concepts of structure and function. (See, most recently, “Replacing Chemistry with Purpose.”) The framework of materialism is based on randomness, from which, combined with natural selection, any structure theoretically can arise. In this way of thinking, over billions of years, randomly generated structures accidentally began to perform functions, resulting in life on Earth as we know it. That is, all the seemingly designed function in the biosphere is simply a result of randomly generated structures. The appearance of design is an illusion.
What is not an illusion, not even to materialists, is the nearly unfathomable complexity of function carried out, nanosecond by nanosecond, in every living creature since life first arose. From the time you started reading this article, perhaps 60 seconds ago, trillions upon trillions of discrete exquisitely tuned chemical reactions took place in your body. And that has been going on since the time that your father’s sperm met your mother’s egg.
And so of course no one argues the fact that function is real.
But Is It Designed?
The funny thing about function is that it is utterly dependent on context. You could have cells with insulin receptors so that glucose is allowed into the cytoplasm from the extracellular compartment. That chemical reaction, even by itself, is enormously complex. But then what? Without all the necessary enzymes to convert glucose and oxygen into ATP, which is another 20 or so extraordinarily exquisite metabolic steps, the entry of glucose into the cell by itself is meaningless. Purpose is only served when the entire series of molecular events achieves the end, the telos, that it was designed to accomplish: benefit the host.
This straightforward analysis creates a conundrum for the materialist who wants to maintain that function emerges out of randomly generated structures. Let’s say the primordial soup randomly generated lipid-encasing vesicles that let glucose in and out. You might call this a mechanical operation, but it is not a function. Function only has meaning when it serves a purpose, and purpose only materializes when it serves a self.
It Is Really That Simple
Function and purpose are meaningless terms absent a self that benefits from their realization. You can pound a board with a hammer all you want. But until you put a nail between the hammer and the board, so that the board attaches to some other object that creates a structure that achieves the end that the carpenter intended, you have accomplished nothing. No function has been carried out. No purpose served.
Professor Terrence Deacon, a distinguished biological anthropologist as well as a widely published author and materialist, has described this confusing state of affairs, even coining a word, “ententional,” to help to characterize it. In his book Incomplete Nature: How Mind Emerged from Matter, he asks how “teleological appearances of living processes [can] be accounted for…Investigators could neither accept ententional properties as foundational nor deny their reality, despite this apparent incompatibility.” (p. 147)
Scientists have learned over the centuries that when a fundamental theoretical impasse is encountered, we do not blame nature. We must blame the theory that fails to account for the observed natural phenomenon.
Something is missing from the theoretical framework of natural science if it cannot explain the function and purpose that are ubiquitous in life. And yes, the answer is there in plain sight in Professor Deacon’s own words. The truth is that “intentional” properties are foundational. They are the genesis of all purpose in life.
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