In 1806 a chemistry book appeared in London without its author’s name. It took the form of conversations between a teacher, Mrs B., and two young pupils, Emily and Caroline, and it opened with an apology. The author, “herself a woman,” conceived that some explanation might be required for offering the public an introduction to chemistry, and felt it the more necessary to apologise “as her knowledge of the subject is but recent, and as she can have no real claims to the title of chemist.” The writer was Jane Marcet. She had learned her chemistry by attending the fashionable lectures of Humphry Davy at the Royal Institution, and her Conversations on Chemistry went on to sixteen editions in Britain and twenty-three printings in America, some of them issued under the names of American men who added pages of their own and put themselves on the title page. Her own name did not appear on the book until 1832.
The apology is charming and, I think, mistaken about its own subject. The recentness of Marcet’s knowledge was not a weakness to be excused. It was her qualification. She still remembered what it had been like not to know, which questions a beginner asks and in what order, which word in a definition blocks the way and which picture opens it. Emily and Caroline ask what a newcomer would ask, and Mrs B. answers at the speed a newcomer can follow. Within a few years of its appearance, an apprentice in a London bookbinder’s shop read it. His name was Michael Faraday, and he later credited Marcet’s book with sparking his interest in science.
This essay is about explanation, and about the kind of teacher who practises it well: the teacher who makes a subject make sense, whom many students meet once or twice in a schooling and remember long after they have forgotten the rest of the timetable. It names no such teacher and reconstructs no lesson. The subject is the act itself, what it gives, what it costs, and why it deserves to be called generous, with one piece of chemistry worked through along the way so that the act can be watched rather than merely praised. Chemistry is the right subject for it. It is the science every pre-medical student must pass through, and the one that most often arrives first as a list.
A Recent Knowledge #
The people who know a subject best are not always the people who explain it best, and economists have given the reason a memorable name. In 1989 Colin Camerer, George Loewenstein and Martin Weber published a paper in the Journal of Political Economy called “The Curse of Knowledge in Economic Settings.” Its subject was the difficulty that better-informed people have in setting aside what they know when they try to predict how less-informed people will judge a situation. Knowledge, once acquired, is hard to subtract. The expert cannot easily remember the shape of his own former ignorance, and so he explains from the far side of a gap he no longer sees.
That is why the first act of a good explanation is an act of imagination, and why I call it generous. Before the explainer says anything useful, he has to reconstruct a mind that is not his own: what it already has, what it lacks, and where precisely the two fail to meet. This is effort spent entirely for someone else’s benefit. It earns the explainer nothing that he did not already possess. He already understands the subject; the work of re-imagining it from outside is pure expenditure, and it is expenditure most experts are disinclined to make, because it involves pretending, for a while, to be less than they are.
Marcet did not need to pretend, because her ignorance was recent, and the circle of her book’s influence makes the point better than any argument. Faraday, apprenticed at fourteen to the bookbinder George Riebau, read the books that passed through the shop. In 1812, at the end of his apprenticeship, he attended lectures by Davy himself, took notes, bound them into a volume of some three hundred pages, and sent it to the lecturer. In 1813 Davy took him on as an assistant. Thirty-two years later, when Marcet was revising her book once more, she wrote to Faraday, by then a Fellow of the Royal Society and one of the most famous scientists in Europe, to ask for details of his latest research, and he supplied them to the author who had first set him on the road. The pupil became the source of the teacher’s revision. Explanation had gone round the circle and come back improved.
A Vocabulary Without a Grammar #
The confusion that a good explanation repairs is rarely stupidity. More often it is a vocabulary without a grammar: a learner in possession of many correct pieces and no rule that connects them.
School chemistry in many places has long begun this way. A student learns symbols, then valencies, then formulas. Valency arrives as a number attached to each element, to be memorised like a telephone number: hydrogen one, oxygen two, nitrogen three, carbon four; sodium one, magnesium two, aluminium three. Then comes a trick for writing formulas. Write the two symbols side by side, cross over their valencies as subscripts, and simplify. Aluminium three and oxygen two give Al₂O₃. Magnesium two and chlorine one give MgCl₂. The trick works. A diligent student can produce correct formulas for a whole page of compounds without the faintest idea why aluminium should be three or oxygen two, or why the numbers should be crossed rather than added or multiplied. He has an answer. He does not have a model.
The chemist and educator Alex Johnstone, writing in 1991 under the wry title “Why is science difficult to learn? Things are seldom what they seem,” gave the most useful account I know of why this stage is so hard. Chemistry, he argued, is taught on three levels at once: the visible level of powders, gases and colour changes; the invisible level of atoms, ions and molecules; and the symbolic level of formulas and equations. Experts move between the three without noticing. Beginners are asked to hold all three in a working memory that has room for only a few items at a time, and they survive by retreating to the one level that can be memorised, the symbols. The crossing trick is a perfect specimen of that retreat. It lives entirely on the symbolic level. It asks nothing of the invisible level, where the reasons are.
To locate a confusion of this kind, the explainer first has to let it speak. Plato staged the method in the Meno, where Socrates draws a square and asks an untaught slave boy how long the side of a square twice its area must be. The boy answers at once that the side must be doubled. It is wrong, and Socrates makes no attempt to correct it by announcement. He lets the boy follow his own answer until it produces a square four times the original instead of twice, then tries again with a side of three, which also fails, until the boy admits that he does not know. Socrates turns to Meno with evident satisfaction. At first the boy “thought that he knew, and answered confidently as if he knew”; now he has a difficulty, “and neither knows nor fancies that he knows.” The next step, the diagonal, can only be taken after that. One need not accept Socrates’ claim that he is not teaching, only asking, to admire what he does. He treats the wrong answer as information about the learner’s model, not as a mark against him, and he does not supply the right answer until the wrong one has been examined and set down.
The Decisive Move #
Here, then, is the piece of chemistry, offered in the spirit the essay is praising. The move that turns valency from a list into sense is a single idea about the invisible level: an atom’s electrons are arranged in shells around its nucleus, and only the outermost shell takes part in ordinary chemical combination.
Count the electrons shell by shell for the first twenty elements and a pattern appears. The innermost shell holds two, the next holds eight, the third, for these light elements, eight more. Sodium has eleven electrons, arranged two, eight, one: a single electron alone in its outer shell. Chlorine has seventeen, arranged two, eight, seven: one short of eight. Neon, two and eight, and argon, two, eight and eight, have outer shells exactly full, and these are the gases that were long known for refusing to combine with anything. Now the idea that changes the question: atoms combine in ways that leave them with the electron arrangement of the nearest such gas, by giving up electrons, taking them, or sharing them.
Everything on the memorised list follows. Sodium gives up its one outer electron and chlorine takes it, so they combine one to one, and the formula is NaCl. Magnesium, two, eight, two, has two to give; each chlorine can take only one; so one magnesium needs two chlorines, MgCl₂. Oxygen, two and six, needs two more, and a hydrogen atom can share one, so oxygen takes two hydrogens, H₂O. Carbon, two and four, sits halfway and shares four, so CH₄. Valency is not a property to be memorised. It is the number of electrons an atom must lose, gain or share to reach a filled outer shell, and it can be read off from the atom’s position in the periodic table, because the table’s columns are, it turns out, families of atoms with the same number of outer electrons. The crossing trick, too, stops being a trick. It is a shorthand for balancing what one atom gives against what the other takes.
The test of the move is what the learner can now do that he could not do before. Ask for the formula of a compound that was never on any list: calcium with fluorine, say. Calcium, two, eight, eight, two, has two to give; fluorine, two and seven, can take one; so CaF₂. Aluminium with sulphur: aluminium has three to give, sulphur needs two; the smallest numbers that balance are two aluminiums giving six electrons to three sulphurs taking two each, Al₂S₃. The student who memorised valencies could have produced these answers too, if both numbers happened to be on his list. The student who understood shells can produce them for pairs he has never seen, and can say why. That difference, between retrieving an answer and generating one, is the clearest sign I know that an explanation has done its work. The question in the student’s head has changed its form. It is no longer what is the valency of aluminium? It is how many electrons does aluminium have to lose?, and that question carries its own method of answer.
Oliver Goldsmith drew the other kind of teacher in The Deserted Village, published in 1770. His village schoolmaster was severe and kind by turns, could write and cipher, measure lands and presage tides, and argued so well that “e’en though vanquish’d, he could argue still.” The villagers stood round him while “words of learned length, and thundering sound / Amazed the gazing rustics ranged around,” and the passage ends with the most famous couplet in the poem:
And still they gazed, and still the wonder grew That one small head could carry all he knew.
It is an affectionate portrait, and its affection is aimed at the right man for the wrong reason. What the rustics admire is possession. The schoolmaster’s knowledge is a marvel because it stays in his head, and the wonder grows in proportion to the distance between what he knows and what they do. An explanation works in the opposite direction. It closes the distance, and in closing it the explainer gives up the mystique that knowledge confers on whoever alone possesses it. After a good explanation of valency, the teacher who gave it looks less like a wonder and more like someone who saw a pattern and showed it. That is the deepest sense in which explanation is generous. The explainer spends his own advantage.
Holes in the Map #
A model is worth having because it can be carried somewhere new, and the history of the periodic table contains the most dramatic instance of that in all of science.
When Dmitri Mendeleev published his table in 1869, arranging the known elements by atomic weight and by recurring properties, he did something bolder than arrange. He left gaps. Where the pattern required an element that no one had found, he left the place empty, and in 1871 he described what would fill some of the empty places. He gave the missing elements provisional names built from Sanskrit numerals: eka-aluminium, eka-boron, eka-silicon, eka meaning one, the element one place beyond the known one in its family. There is something touching in a Russian chemist reaching for a language of the Indian subcontinent to name what nobody had yet seen. Gallium, matching eka-aluminium, was found in 1875; scandium, matching eka-boron, was isolated in 1879. Germanium was isolated in 1886 and gave the most striking confirmation of all. For eka-silicon Mendeleev had predicted an atomic weight of 72 and a density of 5.5. Germanium came in at about 72.6, with a density of about 5.3.
The episode contains a lesson that is easy to miss. Mendeleev’s table predicted without explaining. He knew nothing of electrons or shells; the idea that atoms combine by rearranging their outer electrons was worked out decades later, by Gilbert Lewis in 1916 and Irving Langmuir, who popularised the name octet, in 1919. The pattern came first and worked; the explanation came later and made the pattern intelligible. A student who learns the table before learning why it has its shape is, in a small way, repeating the history of chemistry, and the moment when the shells arrive and the columns suddenly mean something is a private reenactment of what happened to the science between 1869 and the years of the First World War.
The same history marks the edges of the model, and they are as instructive as its triumphs. Mendeleev’s table did not foresee an entire family of elements. When argon was isolated in the 1890s, followed by its relatives, there was no column waiting for them, and it was only in 1902, having accepted the evidence, that Mendeleev placed the noble gases in a group of their own, Group 0. They were the very gases whose filled shells would later anchor the octet. In the same years he reasoned his way toward elements that did not exist at all: conjectured gases lighter than hydrogen that might constitute the ether, and an element identified with coronium, named for an unexplained line in the spectrum of the Sun’s corona, which was shown in 1939 to come from highly ionised iron. A model that could predict germanium so closely could also, pushed beyond its evidence, produce phantoms. The lesson for anyone who explains is plain: a good explanation is offered as something that can be tested, and therefore as something that can be found wrong.
What makes such a moment hold? Cognitive scientists have studied the question with less romance and more precision. In 1989 Michelene Chi and her colleagues analysed what students said aloud while studying worked examples of problems in mechanics. The students who learned well, they found, generated many explanations of their own as they went, explaining to themselves why each step of the solution was taken and connecting it to a principle in the text, and they monitored accurately where their understanding held and where it did not. Those who learned poorly produced few such explanations, misjudged their own understanding, and leaned heavily on the examples when they later tried to solve problems. The good students ended up with knowledge independent of the examples; the poor ones remained tied to them. An explanation offered by a teacher, in other words, is not received like a parcel. It has to be rebuilt inside the learner by the learner’s own explaining, and the sign that it has been rebuilt is that it can be taken somewhere the example never went.
The Second Attempt #
Many explanations fail the first time. This is not a scandal; it is the normal condition of trying to reach a mind one cannot see. What distinguishes a generous explainer is less the brilliance of the first attempt than the willingness to make a second, and a third, each time adjusting to what the failure revealed. The second attempt is the more generous of the two, because by then the explainer knows his first effort was not enough, and the easy conclusion, that the learner is slow, is right there to be taken.
Faraday understood repetition as a gift rather than a chore. Between 1827 and 1860 he gave nineteen series of the Royal Institution’s Christmas lectures for young people, and when he took up The Chemical History of a Candle in 1860 he had given it once before, in 1848. He told his audience so at the start. He had taken the subject on a former occasion, he said, “and were it left to my own will, I should prefer to repeat it almost every year.” He chose the candle because it was familiar to every child in the hall: “There is no better, there is no more open door by which you can enter into the study of natural philosophy, than by considering the physical phenomena of a candle.” And then, with the knowledge that his words would be printed and read by his seniors, he set the seniors aside: “I claim the privilege of speaking to juveniles as a juvenile myself.”
That sentence is the best short definition of explanatory generosity I know. Faraday, by then among the most celebrated experimental scientists in Britain, claims the right to stand where his listeners stand. He does not pretend to be ignorant. He chooses an object they already hold in their hands and walks from it into combustion, water, hydrogen, oxygen and the carbon in their own breath, at a pace set by their curiosity rather than his learning. The candle is his crossing-point between Johnstone’s three levels: a thing anyone can see, made to disclose the invisible, before the symbols are introduced.
Punjabi grammar puts the labour of all this where it belongs, inside the verb. To understand is ਸਮਝਣਾ (samajhṇā); to explain is ਸਮਝਾਉਣਾ (samjhāuṇā), its causative, to cause someone else to understand. To read or study is ਪੜ੍ਹਨਾ (paṛhnā); to teach is ਪੜ੍ਹਾਉਣਾ (paṛhāuṇā), to cause someone else’s reading to happen. The grammar does not let the teacher’s work be described as transmission, as though knowledge were poured from one vessel to another. It describes it as making something occur in another person, which is an undertaking whose success depends on that person, and which the teacher therefore cannot complete alone.
The causative has a second edge, and the edge matters. ਸਮਝਾਉਣਾ also means to counsel, to reason with, sometimes to admonish: one says it of an elder talking sense into a young man bent on a foolish course. The same verb covers the explanation that frees and the persuasion that presses. That is a fair warning about explanation in general. An explainer holds power over the learner’s picture of the world, and the power can be used to make him see or merely to make him agree. The generous explanation leaves the learner able to check it, and therefore able to disagree with it. It hands over the method along with the conclusion, which is exactly what the electron shells do for valency and what the crossing trick does not.
A physician lives inside this verb more than he usually admits. Much of a clinic day is explanation in the causative mood: making a diagnosis, a risk, a choice between two imperfect treatments understood by someone whose training is in some other field entirely, often while frightened. The curse of knowledge sits in the room with every such conversation. A word like benign, or chronic, or negative, which the doctor hears as information, may land on the patient as reassurance, sentence or riddle. Health-literacy practice has a modest technique for this, usually called teach-back, in which the clinician asks the patient to explain in his own words what was just said, not as a test of the patient but as a test of the explanation. It is Chi’s finding turned into a habit of courtesy: the explanation counts as given only when it can be rebuilt by the person who received it. What the chemistry teacher does for valency, the clinician must do for a prognosis, and the two kinds of explaining fail in the same way when the explainer forgets that he was once on the other side of the knowledge.
Telling and Withholding #
The sharpest doubt about all this comes from the classroom, not from cynicism. Perhaps explanation is not generous at all. Perhaps it is the easy kindness that robs the learner of the struggle by which understanding is actually made, the way a parent who always ties the child’s shoes is kind in the moment and unhelpful in the long run. Socrates, in the same dialogue, announces his method as a refusal to explain: “I shall only ask him, and not teach him, and he shall share the enquiry with me.” A long line of educational thought has followed him, holding that what a learner discovers for himself he keeps, and what he is told he borrows.
The argument has evidence on its side, though not all of it. In 2008 the education researcher Manu Kapur gave the name productive failure to a design in which students first wrestle with a problem they are not yet equipped to solve, and only afterwards receive instruction. A meta-analysis that he published with Tanmay Sinha in 2021, pooling fifty-three studies and 166 comparisons, found a moderate advantage for problem-solving followed by instruction over the reverse order, and a stronger one when the design was carried out faithfully. The same analysis found the advantage reversed for the youngest children studied and for general skills. On the other side stands a well-known paper by Paul Kirschner, John Sweller and Richard Clark, published in 2006 under the blunt title “Why Minimal Guidance During Instruction Does Not Work,” which argued that discovery, inquiry and problem-based methods fail novices precisely because novices lack the knowledge that would let them learn from unguided struggle; their working memories are consumed by the search, and little is left for learning.
I do not think the debate is settled, and I am not qualified to settle it. But it clarifies what generosity in explanation actually requires. Neither side argues for leaving a learner alone with a problem indefinitely, and neither argues for reciting conclusions to a mind that has not yet felt the question. Kapur’s students struggle first and are then taught; their failure is productive because explanation follows it and makes use of it. Socrates’ slave boy is allowed his wrong answers, and then Socrates draws the diagonal, which is to say he shows him. The generous teacher’s real skill is timing: judging when the learner has struggled enough for the explanation to land on a prepared question, and not so long that struggle turns into the conclusion that the subject is closed to him. Withholding is generous only when it is a stage of explaining. Withholding as a permanent policy is merely another way of keeping the knowledge in one small head.
What the Pupil Brought #
Gratitude has a way of erasing its owner. When a student remembers the teacher who made chemistry make sense, the memory tends to compress: one lesson, one blackboard, one sentence, and after it the subject lay open. The compression is understandable and almost certainly false. Understanding of anything worth understanding is built over many encounters: a textbook paragraph that half-explained, an examination question that exposed the missing half, a second teacher who used a different picture, a problem that refused to come out until it did. Memory assigns the whole achievement to the most vivid of those occasions, and the most vivid is usually the one that came last, when the remaining piece fell into place and the learner felt the click.
The click belongs partly to the learner. Faraday’s story is usually told as one of patronage, the bookbinder’s boy discovered by the great Davy, but it was Faraday who read the books that passed through Riebau’s shop instead of merely binding them, who worked through Isaac Watts’s The Improvement of the Mind and tried to follow its advice, who joined the City Philosophical Society and attended its lectures, and who turned his notes on Davy’s lectures into a bound volume fit to send to their author. Marcet’s book found him prepared. Chi’s good students were good not because their examples were better but because of what they did with them. A gratitude that forgets the pupil’s labour is, in its way, a small injustice to the pupil, and the pupil is usually the one telling the story.
None of this diminishes the teacher. It locates the teacher’s gift more exactly. A good explanation does not do the learner’s work. It makes the learner’s work possible, by giving it a shape it can take: a question that can be asked of each new compound, a picture that can be checked against each new fact. The explainer supplies the frame. The learner supplies the effort that fills it, many times over, until the frame becomes his own. When both have done their part, the result feels, from the inside, as though it came all at once from the teacher. It did not. It came from the meeting.
Where the Octet Breaks #
Every explanation offered to a beginner is a simplification, and every simplification has an edge beyond which it fails. The generous explainer knows where the edge is, and says so.
The account of valency given above is usually taught in a form that adds one dangerous word. Atoms, students are told, want a full outer shell of eight. Sodium wants to lose its electron; chlorine wants to gain one; they meet and both are satisfied. The language is vivid and easy to remember, and it is wrong in a way that matters. Removing the outer electron from an isolated sodium atom does not satisfy any desire; it costs energy, about 5.1 electron-volts per atom. Adding an electron to an isolated chlorine atom releases less than that, about 3.6. Taken alone, the exchange is a losing bargain. Sodium chloride forms, and forms readily, because the resulting ions pack into a crystal, and the electrical attraction of positive and negative ions in that lattice releases a great deal more energy, around 8 electron-volts per pair, which pays the deficit with plenty to spare. The atoms do not want anything. The arrangement as a whole ends up lower in energy than the separate parts, and the full shells are part of that accounting, not its motive.
The chemistry educator Keith Taber, in a 1998 paper in the International Journal of Science Education titled “An alternative conceptual framework from chemistry education,” described what happens when students take the octet too literally: it hardens into a framework of its own, in which atoms are agents seeking full shells, and that framework then gets in the way of the more accurate ideas that later study requires. The simplification, offered generously, becomes an obstacle when it is not handed over with its limits.
The limits are not obscure. The gases at the end of each row were long called inert, and textbooks said they formed no compounds at all. On Friday, 23 March 1962, at the University of British Columbia, Neil Bartlett mixed xenon with platinum hexafluoride and obtained a solid, the first compound of a noble gas; other chemists soon made several fluorides of xenon, and the word inert had to be retired. In the usual drawing of sulphur hexafluoride, the sulphur atom is surrounded by twelve shared electrons rather than eight. The transition metals in the middle of the table obey the octet hardly at all. The rule of eight is an excellent account of the lighter elements in their commonest compounds and a poor account of a good deal else.
None of this means the simplification should not be taught. A beginner who is given the full quantum-mechanical account first will understand nothing, and a teacher who refuses to simplify is refusing to explain. What it means is that the simplification should be given with its expiry date written on it. The phrase need not be elaborate: this picture will carry you a long way; it is not literally true; later you will meet compounds it cannot describe, and they will not be exceptions to chemistry, only to the picture. A learner told that will not be betrayed when xenon reacts. A learner not told it may be, and may conclude, wrongly, that chemistry itself is arbitrary, when the arbitrariness was in the explanation’s unstated claim to completeness.
Puran Singh, one of the founders of modern Punjabi poetry, knew both sides of this from the inside. Born in Abbottabad in 1881, he went to Tokyo in 1900 on a scholarship and studied pharmaceutical chemistry there until 1903; later, from 1907 until 1918, he worked as a forest chemist at the Forest Research Institute in Dehradun, publishing notes with titles such as A note on the analysis of cutch and preparation of pure catechin and Note on the Manufacture of Ngai Camphor. The same man wrote some of the most expansive free verse in the language. It would be easy to make him a symbol of the scientist redeemed by poetry, and I distrust that move. The better lesson is plainer. The exact prose of the forest chemist and the wide lines of the poet did not cancel each other. Explanation does not dissolve wonder; it relocates it, from the man who knows to the thing that is known. Goldsmith’s rustics marvelled at a head. Puran Singh’s poems, like Faraday’s candle, marvel at the world, and the marvel survives the analysis because it was never resting on the ignorance of the audience in the first place.
Gratitude with Accurate Edges #
What, then, can honestly be credited to the teacher who makes a subject make sense?
Not a career. A single explanation does not decide a life, and to claim that it did would be to tell a story about the teacher that serves mainly the person telling it. Not a mind either; minds are made by too many hands. What can be credited is narrower and more durable: a changed question. Before the explanation, the learner asked what the valency of aluminium was and looked it up or remembered it. After it, he asks how many electrons aluminium has to lose, and finds the answer himself, and can find it for elements nobody listed. The explanation altered the form of his questions, and the altered form outlasts the occasion, the classroom and even the memory of who was standing at the board.
An essay about the act can leave its practitioners unnamed. Naming would turn an act into a portrait, and a portrait asks for details: a voice, a phrase, a particular afternoon. The act needs none of them. It is visible in the result, in every formula worked out rather than retrieved. Gratitude with accurate edges says what was given and leaves what was not known unknown.
Marcet thought she had to apologise because her knowledge was recent. It was the most useful thing about her. Explanation, at its best, is a deliberate return to recentness: the expert agreeing, for the length of a lesson, to stand again where the beginner stands, and to spend there the advantage that his knowledge gave him. It costs him something. It gives the learner a question he can carry. And sometimes, as with Mrs B. and the apprentice who read her, it comes back years later as a letter from the teacher asking the former pupil to help correct the next edition, which is the best return any explanation can hope for, and a reminder that the generosity was never meant to run in one direction only.
Evidence and Editorial Note #
Documented findings. The essay relies on the author’s public biography: pre-medical studies at Khalsa College, Amritsar, and medical training; Punjabi as first language. Jane Marcet, Conversations on Chemistry (1806 according to the Science History Institute, 1805 in some other accounts; anonymous; Mrs B., Emily and Caroline; Davy’s lectures; the preface quoted; 16 British editions and 23 American printings; American editions under men’s names; her name first in 1832; her 1845 letter to Faraday for a revised edition; Faraday reading the book as an apprentice and crediting it): Margaret E. Wood, “Mrs. Chemistry,” Distillations, Science History Institute (2010), and John H. Lienhard, The Engines of Our Ingenuity, episodes 741 and 744 (University of Houston). Faraday’s apprenticeship to George Riebau at fourteen, Watts’s The Improvement of the Mind, the City Philosophical Society, the 1812 Davy lectures, the bound notes of some 300 pages, appointment as Davy’s assistant in 1813, and nineteen Christmas lecture series between 1827 and 1860: Wikipedia, “Michael Faraday.” The Chemical History of a Candle, given in 1848 and in 1860 and printed in 1861: Wikipedia, “The Chemical History of a Candle” and “Royal Institution Christmas Lectures”; passages quoted from the Project Gutenberg text. Camerer, Loewenstein and Weber, “The Curse of Knowledge in Economic Settings: An Experimental Analysis,” Journal of Political Economy 97 (1989): 1232–1254, and A. H. Johnstone, “Why is science difficult to learn? Things are seldom what they seem,” Journal of Computer Assisted Learning 7 (1991): 75–83: bibliographic records and abstracts (Crossref); the summaries of their arguments (the curse of knowledge; macro, sub-micro and symbolic levels and working-memory load) are standard reference knowledge. M. T. H. Chi, M. Bassok, M. W. Lewis, P. Reimann and R. Glaser, “Self-explanations: How students study and use examples in learning to solve problems,” Cognitive Science 13 (1989): 145–182: abstract (Crossref). K. S. Taber, “An alternative conceptual framework from chemistry education,” International Journal of Science Education 20 (1998): 597–608: bibliographic record; the description of the octet framework is standard reference knowledge in chemistry education. Plato, Meno, Jowett translation (Project Gutenberg), for the slave-boy passage and quotations, including “I shall only ask him, and not teach him.” M. Kapur, “Productive Failure,” Cognition and Instruction 26 (2008): 379–424 (bibliographic record, Crossref); T. Sinha and M. Kapur, “When Problem Solving Followed by Instruction Works: Evidence for Productive Failure,” Review of Educational Research 91 (2021): 761–798 (abstract, Crossref: 53 studies, 166 comparisons, moderate effect favouring problem solving first, reversed trends for younger learners and domain-general skills); P. A. Kirschner, J. Sweller and R. E. Clark, “Why Minimal Guidance During Instruction Does Not Work,” Educational Psychologist 41 (2006): 75–86 (bibliographic record, Crossref; its argument summarised as standard reference knowledge). Teach-back as a health-literacy technique: standard reference knowledge. Goldsmith, The Deserted Village (1770), quoted from the Project Gutenberg illustrated edition. Electron shells, valency and the formulas used: standard chemistry. Sodium ionisation energy (about 5.14 eV, 495.8 kJ/mol), chloride formation (about 3.62 eV) and the sodium chloride lattice energy (about 8.12 eV, 783 kJ/mol): Wikipedia, “Octet rule,” citing Housecroft and Sharpe. Lewis (1916) and Langmuir (1919): Wikipedia, “Octet rule.” Mendeleev’s 1869 table, the 1871 predictions with Sanskrit prefixes, gallium (1875), scandium (1879), germanium (1886) and the eka-silicon figures, his placing of the noble gases in Group 0 in 1902, the conjectured ether elements, and coronium’s identification with ionised iron in 1939: Wikipedia, “Mendeleev’s predicted elements.” The isolation of argon in the 1890s: standard reference knowledge. Neil Bartlett’s experiment of 23 March 1962 at the University of British Columbia, the further xenon fluorides that followed, and the earlier belief that noble gases were entirely inert: Wikipedia, “Xenon hexafluoroplatinate” and “Neil Bartlett (chemist).” Sulphur hexafluoride and transition-metal exceptions to the octet: standard chemistry. Puran Singh’s birth in Abbottabad in 1881, chemistry studies in Tokyo 1900–1903, work as research chemist at the Forest Research Institute, Dehradun (about 1908–18), the titles of his technical notes, and his place among the founders of modern Punjabi poetry: Wikipedia, “Puran Singh.” Punjabi ਸਮਝਣਾ/ਸਮਝਾਉਣਾ and ਪੜ੍ਹਨਾ/ਪੜ੍ਹਾਉਣਾ and the counselling sense of ਸਮਝਾਉਣਾ: standard Punjabi usage. Vendor representations. None.
Recollection and tradition. That the author pursued pre-medical studies is part of his published biography. No teacher is named, described or invented, and no lesson, classroom, textbook, examination or moment of understanding from the author’s own schooling is reconstructed. The worked chemistry is the essay’s own explanation addressed to the reader, not a remembered lesson. The remarks on explaining to patients describe clinical conversation in general terms; no patient or encounter is described. The account of how gratitude compresses memory is a general reflection, not a claim about the author’s memories.
Analysis and forecast. The description of explanation as generosity, the readings of Marcet, Plato, Goldsmith, Faraday and Puran Singh, the distinction between retrieving and generating an answer, and the view that simplifications should be taught with their limits are the author’s interpretation as of November 6, 2026. Independence. This essay is not sponsored by any institution, company, health system or technology developer. It is personal reflection, not medical advice; readers seeking care should contact their own physician’s office.
About the Author #
Kanwar Partap Singh Gill, MD, traces his family roots to Khadur Sahib in Punjab’s Majha region and grew up in Amritsar. He attended Spring Dale School and completed pre-medical studies at Khalsa College in 1994–1996. He earned his MBBS from Sri Guru Ram Das Institute of Medical Sciences and Research in Amritsar in 2002.
He completed PGY-1 at the University of Arkansas for Medical Sciences in Little Rock in 2007–2008, and PGY-2 and PGY-3 with UCSF Fresno at Community Regional Medical Center from 2008 through 2010. He has practiced medicine in California since 2010.
His career has crossed four distinct information eras: predominantly paper-based medicine, early and fragmented electronic records, the integrated-EHR era, and the emerging age of generative and agentic artificial intelligence.