Mysterious spiral shells

I have visited one of the most iconic sea forts in Maharashtra – the Sindhudurga at Malvan on the Konkan Coast twice. It is one of the most beautiful sea forts you will witness. The crystal clear waters and blue skies will be imprinted in your memories. The first time I had an analog camera with me, so I couldn’t take as many photos as I would have wanted (one of the analogue snaps is above c. 2001). The second time I had a really nice digital camera with me, so I did take a load of photos (all the ones below).

Maratha navy was a very formidable force on the Konkan coast. The maratha navy under the Angre’s was a force feared by the Portuguese and English alike. They ruled the waters from North of Goa to Colaba Fort (not the same as Colaba in South Bombay) with their capital at Gheria (Vijaydurg), in the later half of 1700s. Maratha navy ships were fastest and very agile in open waters and were absolute terror for the europeans. Anticipating the need for a strong navy as well, Sindhudurga was one of the first sea forts to be built by Shivaji. The fort is built on a rocky outcrop off the coast of Malvan. The fort played an important role after Shivaji as well. It housed Tarabai, the widower queen of younger son Raja Ram during the invasion Mughals. The fort has walls which have stood the test of time and are still standing well even after several centuries against sea water and constant barrage of waves. (though in the second visit we found parts of wall had collapsed). The architecture of the fort is amazing, though we only see the bastions and ramparts now. The fort walls are shaped smoothly when required (in the mathematical sense of continuity), unlike later european forts which are more angular in nature. The front gate is hidden inside a curved pathway between two bastions so that is not visible directly (hence cannot be hit directly with a canon. This mechanism is also seen in several other forts such as Raigad and Janjira. But so much about the fort, coming back to the topic of the post.

On the southern end of the fort there is a small door which opens to a patch of beach. This is one of the best spots on the fort if you are a nature lover. In this small patch there is clear water and beach.

From a bit far
A bit closer to the small door, Sindhudurga Sea Fort Malvan
A bit more close to the small door, Sindhudurga Sea Fort Malvan
Crystal clear waters at Sindhudurga Sea Fort Malvan

The beach sand is coarse, meaning most of it is actually made of seashells. This is a treat to see, myriad shapes, sizes and colours of seashells blended to form the sand. Sand is a fascinating mixture which results from erosion (air, water) and evolution over long time scales. Sand has both inorganic and organic content.

Waves, caustics and crystal clear water…

 

The sea shells are logarithmic in nature, with the nautilus perhaps being seen as exemplary. In many cases of shells the logarithmic spiral is obvious (see the photo), but in other cases as well it shows logarithmic growth.

Close up of the sand shell mix. In the center, Clypidina notata Linne, Size 23-30 mm.
Close up of the sand shell mix. What is this see weed by the way? Upper left white shell is most probably Cardita antiquata Linn  or Cardium sp.
A multishade rock in the sand shell mix
Close up of the sand shell mix, too
Our spiral shell standing out in the sand shell mix
Close up of the sand shell mix. A hermit crab residing in a Trochus radiatus Gmelin (Banded Torchus)
A view of the ramparts and bastion from the small beach
Close up of the sand shell mix, .
Close up of the sand shell mix
Close up of the sand shell mix. This lot needs a lot of identification!
Close up of the sand shell mix
Close up of the sand shell mix. Sundial (Architectonica laevigata Lamarck) with most probably Cardium asiaticum Bruguiere.
A quadrumvirate of hermit crabs in Dwarf turban (Turbo brunneus Röding) with copper legs in a tidal pool near Aguada Fort, Goa)
A company of pebbles (Anjuna beach, Goa)
A company of pebbles (Anjuna beach, Goa)

See a previous post on patterns in nature, this post is a sort of extension of that. For an extensive and excellent treatise on spirals see The Curves of Life by Theodore Cook. On a side note, you should also read Junijo Ito’s spiral themed horror manga Uzumaki.

I did collect a few noteworthy shells from this patch (there were so many to collect!), and these included a few approximately hemispherical ones which were flat on the other side. These shells had a nice logarithmic spiral on the flat side which was also relatively smooth. While the hemispherical side was comparatively rougher.

Now in all other shells, one could easily visualise where would the animal be that created the shell or how the animals used that shell. for example

Connus mutabilis (Reeve) showing excellent spiral structure, from Madh beach
Cantharus spiralis (Gray), from Madh beach
Turritella duplicata (Lamarck) along with a hermit crab, 
Natica didmya (Röding), Revdanda Beach
Burasa tuberculata (Brodip) Tuberculated Frog, Madh Beach
Surcula javana (Linne) Javan Turrid, Nagaon Beach
Mix of organic and mineral sand, Madh Beach
Mix of organic and mineral sand, Madh Beach
Variants of Umbonium vestiarium (Linne), Button shells
Variants of Umbonium vestiarium (Linne), Button shells, Nagaon beach
Variants of Umbonium vestiarium (Linne), Button shells (from Nagaon beach)
Our mysterious spiral shells
Our mysterious spiral shells.
Our mysterious spiral shells
Our mysterious spiral shells

 

But in case of these spirals I could not understand how or where the animal would be using this shell. There was no hole to hide or provide a protection to the animal, as it was solid. It was indeed a puzzle. The shells definitely belonged to an animal, but which one and how did it use it? I asked around but did not get any clear answers. Thus began a journey to unravel the mystery. The image search for spiral shell did not help, though I came to know that these shells are used in astrology oriented rings with silver. And apparently they are seen in jewellery shops.

The first thing we knew for sure was that the shell belonged to a marine animal. But how did that animal use this? It remained an unsolved question for a couple of years. I would ask around to anyone with some knowledge of zoology, but it didn’t get any answers. Then one day someone did faintly recognised, “Isn’t this an operculum?” Now a quick image search with this new term, operculum, I learned gave the answer to this mystery. And commonly it is also known as cat’s eye shell. And the long mystery was solved:

The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of “trapdoor” to close the aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. (wiki)

TODO: Identify all the shells in the photos..

 

References

Deepak Apte – The Book of Indian Shells (BNHS)

 

 

Algorithmic Nature

Such natural beauty! Does mathematics lie at the basis of these diverse and beautiful forms? Photo taken during summer of 2017 in Mumbai. None of these are native to India. On left: The Cannonball tree flower (Couroupita guianensis) is South and Central American, African Tulip Tree (Spathodea campanulata) native to tropical. Africa; On Right: The Cannonball tree flower, and Gulmohar is Madagascan (Delonix regia).

What could be more “organic” and “natural” than looking at a pristine forest with a variety of tree forms and leaf forms of various shapes and shades, with inflorescences of variety of shapes, sizes and colours? Mathematicians and physicists are often accused of being not able to enjoy nature and because mathematics and physical theory is so “abstract” and nature is so “organic”. Organic growth is in the form of variety of morphologies of roots, branches, flowers shapes and arrangement, leaf shapes and arrangements, while mathematics typically is abstract graphs, equations, symbols and numbers. How can these two possibly have anything in common? This has also to do with how biology is traditionally taught. While physics has mathematics at its foundation, the teaching of biology doesn’t acknowledge any need for mathematics – it is mostly descriptive as it was in its early stages a couple of centuries later. This is more so at the school level teaching of biology. So this creates an impression in the students and teachers alike that mathematics is not a part of “biological” nature and it is only reserved for falling bodies and ascending projectiles. 

 

What can be similarities in the two images? One is abstracted representation of motion of a body in algebraic and graphical format and other is organic growth of a plant showing its branching and similar leaves with its pigmentation of chlorophyll.

Of course the variety of forms and their classification is one of the foundations of biology. Linnaeus used the morphological differences and similarities to form his classification system.

 

Linnaean system brought order to seemingly diverse and chaotic forms of natural world. Linnaeus named the different forms. Naming is the first step in studying anything. Naming helps in categorisation, which is one of ways to formation of concepts. This led to further finer classification of the system as whole which now includes both flora and fauna. Then began the programme of finding organisms and classifying them in existing categories with descriptions – or creating new ones when the existing ones did not fit – became the normal way of doing biology in the nineteenth century. Even now finding a new plant or animal species is treated with celebrated as a new discovery. 

Darwin in his thesis about evolution by natural selection used the differences and similarities of the form as one of evidence. He theorised that organisms that have evolved from common ancestors will show similar forms with slight variations. Over long periods of time these slight variations evolve into larger variations which ultimately leads to a completely different species. Fossil records tell us about ancestors and current relatives of organisms.

There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone circling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved. (emphasis added)

The morphologies tell us about related species, the ancestries and divergences from there. The fossils tell us the ancestors, the missing links. So finding organisms, both extant and extinct, to fit in the jigsaw puzzle of tree of life became the standard programme in biology. This enabled us to construct the tree of life. Ernst Haeckel’s version of the tree, depicted below, is highly anthropocentric which places humans at the apex of evolution. This is rather common misconception about evolution – humans are not at apex of evolution or the prime product of it as some would have us believe – we have co-evolved with all the current extant species. Evolution by natural selection is not anthropocentric, it is indifferent to humans and other organisms alike. Daniel Dennett likens it to universal acid, and makes a point that it is not only applicable to living systems, but applies to any system which fulfil the three required criteria. 

 

Haeckel’s – Pedigree of Man – a version of tree of life which is highly anthropocentric.

But can we make sense of similarities of the form in terms of mathematics? Can we find mathematical algorithms which will generate forms, as they generate trajectories of moving projectiles? Looking at similarities in form, it is Galileo who was one of the first to discuss the problem of scaling and its effect on form.

To illustrate briefly, I have sketched a bone whose natural length has been increased three times and whose thickness has been multiplied until, for a correspondingly large animals, it would perform the same function which the small bone performs for its small animal, From the figures here shown you can see how the proportion of the enlarged bone appears. 

Whereas, if the size of a body be diminished, the strength of that body id not diminished in the same proportion; indeed the smaller the body the greater its relative strength. Thus a small dog could probably carry on his back two or three dogs of his own size; but I believe that a horse could not carry even one of his own size.

At the start of twentieth century we had a few  classics which gave a strong mathematical flavour to the study of the biological forms and scaling – The Curves of Life by Theodore Cook (1914), D’arcy Thompson’s  On Growth and Form (1917) and  Julian Huxley’s Problems of Relative Growth (1932)

The kind of mathematical treatment that entered in study of biology by above classics looked at the mathematical aspects of morphological forms in organisms. The Curves of Life looks at the spiral forms which are found in nature, and also in various human creations – architecture and art. 

The spiral is one of the most easily identifiable mathematical forms in nature.
In many flowers, a double spiral forms the basis of the central pattern. The Fibonacci numbers are easily identifiable with this pattern.
The spiral is found in animals too, most easily identifiable in the shells of various types. They represent logarithmic spirals.

 

Despite tremendous success of Darwin’s theory, physics and mathematics were in a separate compartment from biology. There seemed to be no common elements, while biology became more and more descriptive with focus on the form, but not mathematical. 

The word “form” in this article will refer to the shapes of material objects, the arrangement in space of groups of them, and the arrangement in space of their component parts. Our appreciation of form is partly sensory, but we can be helped by measurement and calculation to gain some confidence that what we perceive is not entirely unconnected with the outside world. (Physical Principles underlying Inorganic FormS.P.F. Humphreys-Owen)

But this is a folly. Nature and organic growth is as mathematical as is the description of a projectile flying under gravity. Perhaps the mathematical description is 

The sparse branching of Frangipani (Plumeria sp.), a native of central America.
The dense branching of the Acacia (Vachellia nilotica) native to Africa, Middle East and India. Is the branching in Frangipani and Acacia related? What about the branching in grass in the figure at top? Can these be generated from a single mathematical algorithm? And why do only these forms are found and not any other?

In my experience a lot of young children who take to biology do so because they hate mathematics or computations. In India there are even streams at +2 level which allow you to shun mathematics for biological subjects. This utter hatred for mathematics is, IMHO, due to a carelessly designed and too abstracted mathematics curriculum at the school level – a curriculum which takes out the soul of mathematics and puts on a garish display of the cadaver of mathematics with bells and whistles. But this post is not about the problems of mathematics education, I have talked about it elsewhere.

 

The aim of this series of posts is to touch upon the inherent mathematics and algorithms in the natural world. How nature is mathematical especially in living and non-living things. How can algorithms generate natural forms? In the next posts in this series we will explore how the ideas of mathematical models can explain the variety of forms that result from natural selection in environment and possibly why only those forms can be found. 

Note: All photographs were taken by me over the years. Only now I am able to piece a narrative linking them together.

 

 

John Tukey on data based pictures and graphs

John Tukey‘s wisdom on importance and value of graphics and pictures in making sense of exploring data.

Consistent with this view, we believe, is a clear demand that pictures based on exploration of data should force their messages upon us. Pictures that emphasize what we already know — “security blankets” to reassure us — are frequently not worth the space they take. Pictures that have to be gone over with a reading glass to see the main point are wasteful of time and inadequate of effect. The greatest value of a picture is when it forces us to notice what we never expected to see. (p. vi emphasis in original)

John Tukey – Exploratory Data Analysis

Galileo’s Experiments on Accelerated Motion

A short account of Galileo’s description of his own experiment on accelerated motion — a short account of it, the apparatus he used and the results he got.
The first argument that Salviati proves is that in accelerated motion the change in velocity is in proportion to the time (𝑣 ∝ 𝑡) since the motion began, and not in proportion to the distance covered (𝑣 ∝ 𝑠) as is believed by Sargedo.

“But for one and the same body to fall eight feet and four feet in the same time is possible only in the case of instantaneous (discontinuous) motion; but observation shows us that the motion of a falling body occupies time, and less of it in covering a distance of four feet than of eight feet; therefore it is not true that its velocity increases in proportion to the space. (Salviati)

Also, he proves that the increase in proportion is not of simple doubling but larger. They agree upon a definition of uniformly accelerated motion,

“A motion is said to be equally or uniformly accelerated when, starting from rest, its momentum receives equal increments in equal times. (Sargedo)

To this definition Salviati adds an assumption about inclined planes, this assumption is that for a given body, the increase in speed while moving down the planes of difference inclinations is equal to the height of the plane. This also includes the case if the body is dropped vertically down, it will still gain the same speed at end of the fall as it would gain from rolling on the incline This assumption makes the final speed independent on the profile of the incline. For example, in the figure below, the body falling along𝐶 → 𝐵, 𝐶 → 𝐷 and 𝐶 → 𝐴 will attain the same final speed.

This result is also proved via a thought experiment (though it might be feasible to do this experiment) for a pendulum. The pendulum rises to the height it was released from and not more.
After stating this theorem, Galileo then suggests the experimental verification of the theorem. of The actual apparatus that Galileo uses is an wooden inclined slope of following dimensions: length 12 cubits (≈ 5.5 m, 1 cubit ≈ 45.7 cm), width half-cubit and three-finger breadths thick . In this plank of wood, he creates a very smooth groove which is about a finger thick. (What was the thickness of Galileo’s fingers?) The incline of this plank are changed by lifting one end. A bronze ball is rolled in this groove and time taken for descent is noted.

“We repeated this experiment more than once in order to measure the time with an accuracy such that the deviation between two observations never exceeded one- tenth of a pulse-beat.

Then Galileo performed variations in the experiment by letting the ball go different lengths (not full) of the incline and “found that the spaces traversed were to each other as the squares of the times, and this was true for all inclinations of the plane”. Each variation was repeated hundreds of times so as to rule out any errors. Also, the fact that for different inclines the times of descent were in noted and were in agreement with the predictions.
Since there were no second resolution clocks to measure time, Galileo devised a method to measure time using water. This was not new, water clocks were used earlier also.

The basic idea was to the measure the amount of water that was collected from the start of the motion to its end. The water thus collected was weighed on a good balance.This weight of water was used as a measure of the time. A sort of calibration without actually measuring the quantity itself: “the differences and ratios of these weights gave us the differences and ratios of the times”

Galileo used a long incline, so that he could measure the time of descent with device he had. If a shorted incline was used, it would have been difficult to measure the shorter interval of time with the resolution he had. Measuring the free fall directly was next to impossible with the technology he had. Thus the extrapolation to the free fall was made continuing the pattern that was observed for the “diluted” gravity.

“You present these recondite matters with too much evidence and ease; this great facility makes them less appreciated than they would be had they been presented in a more abstruse manner. For, in my opinion, people esteem more lightly that knowledge which they acquire with so little labor than that acquired through long and obscure discussion. (Sargedo)

 

Reference

Dialogues Concerning Two New Sciences

Book Review: Ages in Chaos by Stephen Baxter

Ages in Chaos is a scientific biography of James Hutton by Stephen Baxter. Hutton was a Scottish scientist who also played his part in Scottish enlightenment. Hutton was the first to speculate on the idea deep time required for geological processes at the end of 1700s arguing with evidence he collected. He was trained as a medical doctor, practiced farming for 10 odd years and had continued his explorations of geology throughout. The prevalent theories of geology, called Neptunists, posited that water was the change agent. Hutton on the other hand posited that it was heat which was responsible for changes, hence Vulcanists. Also, another thing was that of time needed for this change. As others of his era, Hutton was deeply religious, like Newton, wanted to find evidence for creation as per bible.
During his time, especially popular was the idea of flood as per Bible, while the Earth was literally considered to be 6000 years old. This created a problem for Hutton, who was labelled to be atheist and heretic for suggesting that Earth is much older and that there was no design. But Hutton was a conformist and wanted to find a uniform evidence for all observable aspects. He was not like a modern scientist, as he is painted many times. The ideas were vehemently attacked on each point. Though he went to the field to find geological examples for this theory. James Watt, Black and John Playfair were his friends and provided him with evidence in the form of rock samples. During his lifetime, Hutton’s ideas will not find much audience. But due to his friends, his ideas sustained a a barrage of criticisms. Only in the next generation with Lyell this work would find acceptance. This idea of a deep time was crucial in formation Darwin’s theory.
https://www.goodreads.com/book/show/157978.Ages_in_Chaos
The book reads well mostly, but at times a complete lack of illustrations in the forms of geological artefacats and maps (of Scotland) makes it difficult to read well.

Book Review: Pendulum: Léon Foucault and the Triumph of Science by Amir D. Aczel

The book traces Leon Foucault’s ingenious approach to solving the problem of providing a terrestrial proof of rotation of the Earth. The pendulum he devised oscillates in a constant plane, and if properly engineered (as he did) can actually show the rotation of the Earth. The demonstration is one the most visually impressive scientific experiments. Also, Foucault gave prediction, an equation which would tell us how the pendulum will behave at different parts of the Earth. The pure mathematicians and physicists alike were taken aback at this simple yet powerful demonstration of the proof which eluded some of the most brilliant minds, which includes likes of Galileo and Newton. Rushed mathematical proofs were generated, some of the mathematicians earlier had claimed that no such movement was possible. That being said, Foucault was seen as an outsider by the elite French Academy due to his lack of training and degree. Yet he was good in designign things and making connections to science. This was presented to the public in 1851, and the very next year in 1852 he created another proof for rotation of the Earth. This was done by him inventing the gyroscope.. Gyroscope now plays immense role in navigation and other technologies. Yet he was denied membership to the Academy, only due to interest of the Emperor Napolean III in his work in 1864. The pendulum is his most famous work, but other works are also of fundamental significance.

  • He was first person to do photomicrography using Daguerreotype
  • Accurate measurment of speed of light using rotating mirrors –
  • Devised carbon arc electric lamp for lighting of micrcoscope
  • One of the first to Daguerreotype the Sun
  • Designed the tracking systems used in telescopes
  • also designed many motors, regulators to control electrical devices

There are a couple of places in the book where Aczel seems to be confused, at one point he states parallax as a proof for rotation of Earth around its axis, whearas it is more of a proof of Earths motion around the Sun. At another place he states that steel was invented in 1800s which perhaps he means to say that it was introduced in the west at the time. Apart from this the parallels between the rise of Napoleon III, a Nephew of Napolean, to form the second Empire in France and Foucault’s own struggle for recognition of his work and worth is brought out nicely.

Rotating Earth: the proofs or significance of Leon Foucault’s pendulum – Part 1

rotating-earth
In an earlier post, we had discussed proofs of the round shape of the Earth. This included some ancient and some modern proofs. There was, in general, a consensus that the shape of the Earth was spherical and not flat and the proofs were given since the time of ancient Greeks. Only in the middle ages, there seems to have been some doubt regarding the shape of the Earth. But amongst the learned people, there was never a doubt about the shape of the Earth. Counter-intuitive it may seem when you look at the near horizon, it is not that counter-intuitive. We can find direct proofs about it by looking around and observing keenly.
But the rotation of Earth proved to be a more difficult beast to tame and is highly counter-intuitive. Your daily experience does not tell you the Earth is rotating, rather intuition tells you that it is fixed and stationary. Though the idea of a moving Earth is not new, the general acceptance of the idea took a very long time. And even almost 350 years after Copernicus’ heliocentric model was accepted, a direct proof of Earth’s rotation was lacking. And this absence of definitive proof was not due to a lack of trying. Some of the greatest minds in science, mathematics and astronomy worked on this problem since Copernicus but were unable to solve it. This included likes of Galileo, Newton, Descartes, and host of incredibly talented mathematicians since the scientific revolution. Until Leon Foucaultin the mid-1800s provided not one but two direct proofs of the rotation of the Earth. In this series of posts, we will see how this happened.
When we say the movement of the Earth, we also have to distinguish between two motions that it has: first its motion about its orbit around the Sun, and second its rotational motion about its own axis. So what possible observational proofs or direct evidence will allow us to detect the two motions? In this post, we will explore how our ideas regarding these two motions of the Earth evolved over time and what type of proofs were given for and against it.

Even more, there was a simple geometrical fact directly opposed to the Earth’s annual motion around the Sun and there was nothing that could directly prove its diurnal rotation. (Mikhailov, 1975)

Let us consider the two components of Earth’s motion. The first is the movement around the Sun along the orbit. The simplest proof for this component of Earth’s motion is from the parallax that we can observe for distant stars. Parallax is the relative change in position of objects when they are viewed from different locations. The simplest example of this can be seen with our own eyes.
Straighten your hand, and hold your thumb out. Observe the thumb with both the eyes open. You will see your thumb at a specific location with respect to the background objects. Now close your left eye, and look at how the position of the thumb has changed with respect to the background objects. Now open the right eye, and close the left one. What we will see is a shift in the background of the thumb. This shift is related by simple geometry to the distance between our eyes, called the baseline in astronomical parlance. Thus even a distance of the order of a few centimetres causes parallax, then if it is assumed that Earth is moving around the Sun, it should definitely cause an observable parallax in the fixed stars. And this was precisely one of the major roadblock

Earth moving around an orbit raised mechanical objections that seemed even more serious in later ages; and it raised a great astronomical difficulty immediately. If the Earth moves in a vast orbit, the pattern of fixed stars should show parallax changes during the year. (Rogers, 1960)

The history of cosmic theories … may without exaggeration be called a history of collective obsessions and controlled schizophrenias.
– Arthur Koestler, The Sleepwalkers

Though it is widely believed that Copernicus was the first to suggest a moving Earth, it is not the case. One of the earliest proponents of the rotating Earth was a Greek philosopher named Aristarchus. One of the books by Heath on Aristarchus is indeed titled Copernicus of Antiquity (Aristarchus of Samos). A longer version of the book is Aristarchus of Samos: The Ancient Copernicus. In his model of the cosmos, Aristarchus imagined the Sun at the centre and the Earth and other planets revolving around it. At the time it was proposed, it was not received well. There were philosophical and scientific reasons for rejecting the model.

aristarchus-01
Aristarchus’s model of the heliocentric Universe

First, let us look at the philosophical reasons. In ancient Greek cosmology, there was a clear and insurmountable distinction between the celestial and the terrestrial. The celestial order and bodies were believed to be perfect, as opposed to the imperfect terrestrial. After watching and recording the uninterrupted waltz of the sky over many millennia, it was believed that the heavens were unchangeable and perfect. The observations revealed that there are two types of “stars”. First the so-called “fixed stars” do not change their positions relative to each other. That is to say, their angular separation remains the same. They move together as a group across the sky. Imagination coupled with a group of stars led to the conceiving of constellations. Different civilizations imagined different heroes, animals, objects in the sky. They formed stories about the constellations. These became entwined with cultures and their myths.
telescope_0013
The second type of stars did change their positions with respect to other “fixed stars”. That is to say, they changed their angular distances with “fixed stars”. These stars, the planets, came to be called as “wandering stars” as opposed to the “fixed stars”.

Ancient Greeks called these lights πλάνητες ἀστέρες (planētes asteres, “wandering stars”) or simply πλανῆται (planētai, “wanderers”),from which today’s word “planet” was derived.
Planet

So how does one make sense of these observations? For the fixed stars, the solution is simple and elegant. One observes the set of stars rising from the east and setting to the west. And this set of stars changes across the year (which can be evidenced by changing seasons around us). And this change was found to be cyclical. Year after year, with observations spanning centuries, we found that the stars seem to be embedded on inside of a sphere, and this sphere rotates at a constant speed. This “model” explains the observed phenomena of fixed stars very well.
The unchanging nature of this cyclical process observed, as opposed to the chaotic nature on Earth, perhaps led to the idea that celestial phenomena are perfect. Also, the religious notion of associating the heavens with gods, perhaps added to them being perfect. So, in the case of perfect unchanging heavens, the speeds of celestial bodies, as evidenced by observing the celestial sphere consisting of “fixed stars” was also to be constant. And since celestial objects were considered as perfect, the two geometrical objects that were regarded as perfect the sphere and the circle were included in the scheme of heavens. To explain the observation of motion of stars through the sky, their rising from the east and setting to the west, it was hypothesized that the stars are embedded on the inside of a sphere, and this sphere rotates at a constant speed. We being fixed on the Earth, observe this rotating sphere as the rising and setting of stars. This model of the world works perfectly and formed the template for explaining the “wandering stars” also.
These two ideas, namely celestial objects placed on a circle/sphere rotating with constant speed, formed the philosophical basis of Greek cosmology which would dominate the Western world for nearly two thousand years. And why would one consider the Earth to be stationary? This is perhaps because the idea is highly counter-intuitive. All our experience tells us that the Earth is stationary. The metaphors that we use like rock-solid refer to an idea of immovable and rigid Earth. Even speculating about movement of Earth, there is no need for something that is so obviously not there. But as the history of science shows us, most of the scientific ideas, with a few exceptions, are highly counter-intuitive. And that the Earth seems to move and rotate is one of the most counter-intuitive thing that we experience in nature.
The celestial observations were correlated with happenings on the Earth. One could, for example, predict seasons as per the rising of certain stars, as was done by ancient Egyptians. Tables containing continuous observations of stars and planets covering several centuries were created and maintained by the Babylonian astronomers. It was this wealth of astronomical data, continuously covering several centuries, that became available to the ancient Greek astronomers as a result of Alexander’s conquest of Persia. Having such a wealth of data led to the formation of better theories, but with the two constraints of circles/spheres and constant speeds mentioned above.
With this background, next, we will consider the progress in these ideas.
A stabilised image of the Milky Way as seen from a moving Earth.

 

Asimov on science literacy

Science literacy does not have a unique definition. Depending on what your ideas about science are, the meaning of science literacy will change. But being scientifically literate, is usually taken as a sign of being informed, being rational in decisions. Here is what the great science and science-fiction writer Issac Asimov had to say about its importance.

A public that does not understand how science works can, all too easily, fall prey to those ignoramuses … who make fun of what they do not understand, or
to the sloganeers who proclaim scientists to be the mercenary warriors of today, and the tools of the military. The difference … between … understanding and not understanding . . . is also the difference between respect and admiration on the one side, and hate and fear on the other.
– Isaac Asimov

 

Why philosophy is so important in science education

This is a nice article whicH I have reposted from AEON…

Each semester, I teach courses on the philosophy of science to undergraduates at the University of New Hampshire. Most of the students take my courses to satisfy general education requirements, and most of them have never taken a philosophy class before.
On the first day of the semester, I try to give them an impression of what the philosophy of science is about. I begin by explaining to them that philosophy addresses issues that can’t be settled by facts alone, and that the philosophy of science is the application of this approach to the domain of science. After this, I explain some concepts that will be central to the course: induction, evidence, and method in scientific enquiry. I tell them that science proceeds by induction, the practices of drawing on past observations to make general claims about what has not yet been observed, but that philosophers see induction as inadequately justified, and therefore problematic for science. I then touch on the difficulty of deciding which evidence fits which hypothesis uniquely, and why getting this right is vital for any scientific research. I let them know that ‘the scientific method’ is not singular and straightforward, and that there are basic disputes about what scientific methodology should look like. Lastly, I stress that although these issues are ‘philosophical’, they nevertheless have real consequences for how science is done.
At this point, I’m often asked questions such as: ‘What are your qualifications?’ ‘Which school did you attend?’ and ‘Are you a scientist?’
Perhaps they ask these questions because, as a female philosopher of Jamaican extraction, I embody an unfamiliar cluster of identities, and they are curious about me. I’m sure that’s partly right, but I think that there’s more to it, because I’ve observed a similar pattern in a philosophy of science course taught by a more stereotypical professor. As a graduate student at Cornell University in New York, I served as a teaching assistant for a course on human nature and evolution. The professor who taught it made a very different physical impression than I do. He was white, male, bearded and in his 60s – the very image of academic authority. But students were skeptical of his views about science, because, as some said, disapprovingly: ‘He isn’t a scientist.’
I think that these responses have to do with concerns about the value of philosophy compared with that of science. It is no wonder that some of my students are doubtful that philosophers have anything useful to say about science. They are aware that prominent scientists have stated publicly that philosophy is irrelevant to science, if not utterly worthless and anachronistic. They know that STEM (science, technology, engineering and mathematics) education is accorded vastly greater importance than anything that the humanities have to offer.
Many of the young people who attend my classes think that philosophy is a fuzzy discipline that’s concerned only with matters of opinion, whereas science is in the business of discovering facts, delivering proofs, and disseminating objective truths. Furthermore, many of them believe that scientists can answer philosophical questions, but philosophers have no business weighing in on scientific ones.
Why do college students so often treat philosophy as wholly distinct from and subordinate to science? In my experience, four reasons stand out.
One has to do with a lack of historical awareness. College students tend to think that departmental divisions mirror sharp divisions in the world, and so they cannot appreciate that philosophy and science, as well as the purported divide between them, are dynamic human creations. Some of the subjects that are now labelled ‘science’ once fell under different headings. Physics, the most secure of the sciences, was once the purview of ‘natural philosophy’. And music was once at home in the faculty of mathematics. The scope of science has both narrowed and broadened, depending on the time and place and cultural contexts where it was practised.
Another reason has to do with concrete results. Science solves real-world problems. It gives us technology: things that we can touch, see and use. It gives us vaccines, GMO crops, and painkillers. Philosophy doesn’t seem, to the students, to have any tangibles to show. But, to the contrary, philosophical tangibles are many: Albert Einstein’s philosophical thought experiments made Cassini possible. Aristotle’s logic is the basis for computer science, which gave us laptops and smartphones. And philosophers’ work on the mind-body problem set the stage for the emergence of neuropsychology and therefore brain-imagining technology. Philosophy has always been quietly at work in the background of science.
A third reason has to do with concerns about truth, objectivity and bias. Science, students insist, is purely objective, and anyone who challenges that view must be misguided. A person is not deemed to be objective if she approaches her research with a set of background assumptions. Instead, she’s ‘ideological’. But all of us are ‘biased’ and our biases fuel the creative work of science. This issue can be difficult to address, because a naive conception of objectivity is so ingrained in the popular image of what science is. To approach it, I invite students to look at something nearby without any presuppositions. I then ask them to tell me what they see. They pause… and then recognise that they can’t interpret their experiences without drawing on prior ideas. Once they notice this, the idea that it can be appropriate to ask questions about objectivity in science ceases to be so strange.
The fourth source of students’ discomfort comes from what they take science education to be. One gets the impression that they think of science as mainly itemising the things that exist – ‘the facts’ – and of science education as teaching them what these facts are. I don’t conform to these expectations. But as a philosopher, I am mainly concerned with how these facts get selected and interpreted, why some are regarded as more significant than others, the ways in which facts are infused with presuppositions, and so on.
Students often respond to these concerns by stating impatiently that facts are facts. But to say that a thing is identical to itself is not to say anything interesting about it. What students mean to say by ‘facts are facts’ is that once we have ‘the facts’ there is no room for interpretation or disagreement.
Why do they think this way? It’s not because this is the way that science is practised but rather, because this is how science is normally taught. There are a daunting number of facts and procedures that students must master if they are to become scientifically literate, and they have only a limited amount of time in which to learn them. Scientists must design their courses to keep up with rapidly expanding empirical knowledge, and they do not have the leisure of devoting hours of class-time to questions that they probably are not trained to address. The unintended consequence is that students often come away from their classes without being aware that philosophical questions are relevant to scientific theory and practice.
But things don’t have to be this way. If the right educational platform is laid, philosophers like me will not have to work against the wind to convince our students that we have something important to say about science. For this we need assistance from our scientist colleagues, whom students see as the only legitimate purveyors of scientific knowledge. I propose an explicit division of labour. Our scientist colleagues should continue to teach the fundamentals of science, but they can help by making clear to their students that science brims with important conceptual, interpretative, methodological and ethical issues that philosophers are uniquely situated to address, and that far from being irrelevant to science, philosophical matters lie at its heart.Aeon counter – do not remove

 
Subrena E Smith
This article was originally published at Aeon and has been republished under Creative Commons.

Thomas Kuhn on the role of textbooks in science education

The single most striking feature of this [science] education is that, to an extent wholly unknown in other fields, it is conducted entirely through textbooks. Typically, undergraduate and graduate students of chemistry, physics, astronomy, geology, or biology acquire the substance of their fields from books written especially for students.

Thomas Kuhn The Essential Tension
Here Kuhn is trying to show us the nature of science education which is usually divergent from the historical processes and events which led to the currently accepted theories. Most of the textbooks rather show the content matter which makes sense conceptually in a rationally organised manner. Of course, the ideal goal, at least in the physical sciences, is to create a hypothetico-deductive model in which a given theory, its predictions, explanations and implications can be derived from some basic definitions and axioms. For example, an introductory text on motion in physics usually starts with definitions and assumptions usually of a mass point, and/or operations that are defined on it. The text does not describe the historical conditions in which this conceptual approach arose, rather it adapts a very pragmatic pedagogical approach. It defines the term and ends it there, but in this process, it redefines the conceptual history. This approach assumes that there is no pedagogical merit or role in introducing a concept in its historical context. This perhaps is also linked to Poppers distinction of the context of discovery and the context of justification. What we see is a rational reconstruction of historical processes to make sense of them in a straightforward manner.