vendredi 26 août 2022

Le diable est tapi dans les laboratoires

1. Introduction

Je sais bien que des amis m'ont dit qu'il ne fallait pas dire "C'est simple", à des étudiants, mais :
1. je crois que ce conseil est mauvais
2. j'ai analysé ma position et je l'ai publiée
3. je crois que, si c'est un encouragement, alors c'est utile
4. quand on avance pas à pas, le plus long des chemins n'est qu'une succession de pas (qui veut voyager loin ménage sa monture, en quelque sorte).

Voir :


En l'occurrence, je propose de voir, avec un nouveau texte, qu'un mélange de calculs simples, formel et numérique, permet d'analyser des cas analytiques pathologiques (en rappelant qu'analyse et synthèse sont indissociables, en chimie et en physico-chimie.

2. La question posée : l'intégration des signaux

Le texte complet est téléchargeable ici :

jeudi 25 août 2022

In English: Atoms, elements, compounds, substances...

It's a mess.
In the Encyclopedia britannica (, I looked for the definition of "chemical compound", and I found a very messy and wrong text.
Indeed, here it is: "chemical compound, any substance composed of identical molecules consisting of atoms of two or more chemical elements".

And immediately, you see the mistake, as a "substance" is a material object: water is a liquid substance, in the ambiant conditions, and iron is a solid substance, with metallic aspect. But water (the substance) is made of identical objects, i.e., molecules ("water molecules"), which are made of atoms of different kinds, such as hydrogen (the element, not to be confused with dihydrogen) or oxygen. And "water" is also the name of the compound "water", i.e. the chemical category of all molecules made of one oxygen atom and two hydrogen atoms.

For sure, the fact that "water" applies to a substance  and a compound creates confusion. Moreover, the word "water" applies to the chemical pure water (substance) as any tap water, or water in the river, or sea water, which are rather aqueous solutions containing a lot of solutes, such as ions, molecules, etc.

Let's read more: "All the matter in the universe is composed of the atoms of more than 100 different chemical elements, which are found both in pure form and combined in chemical compounds."
Yes, no, the matter of the universe is not composed of the atoms of etc."... because there are a lot of subatomic particles, not considering dark matter.

More : " A sample of any given pure element is composed only of the atoms characteristic of that element, and the atoms of each element are unique". No, again : a "pure element" does not exist : an element is an element, a category of atoms, and the question of purity has no meaning here. Purity can only apply to substances, to materials.
And no again, the atoms of an element are not all the same, because some can have more neutrons than others. Wrong again: don't you think it's too much?

More :
"For example, the atoms that constitute carbon are different from those that make up iron, which are in turn different from those of gold." : here, the mistake in the "make up". Stricto sensu, objects don't "make up" a category.

" Every element is designated by a unique symbol consisting of one, two, or three letters arising from either the current element name or its original (often Latin) name." : yes.

"For example, the symbols for carbon, hydrogen, and oxygen are simply C, H, and O, respectively. The symbol for iron is Fe, from its original Latin name ferrum.  : yes.

" The fundamental principle of the science of chemistry is that the atoms of different elements can combine with one another to form chemical compounds." : here, there is a pleonasm, was chemistry being a science, expressions such as "the science of chemistry" is too much.

And here, I have enough, but shouldn't EB make corrections?

vendredi 19 août 2022

Combattons le mercantilisme

 Pas de place pour le mercantilisme, en sciences de la nature !

Je vois apparaître des adjectifs honteux dans des publications qui se disent scientifiques ou technologiques. Par exemple, je vois l'adjectif "unique" ou "remarquable" ou "extraordinaire",  ou encore un "ultrastable" qui doit nous faire penser à cet "ultra-transformé" qui ne signifie rien ; et tout cela n'a rien à faire dans le titre des publications : la science, ce n'est pas le commerce des savonnettes.

D'ailleurs, ces mots n'ont aucun sens, en science, et ils doivent toujours être remplacés par la réponse à la question "Combien ?".

Certes, une caractéristique physique d'une système, par exemple, peut être supérieure à celle d'autres systèmes mieux connus, mais supérieur de combien ? Et c'est une faiblesse d'esprit bien grande (;-)) de croire que c'est   en ajoutant un adverbe qu'on résoudra la question.

Décidément, les éditeurs des journaux scientifiques  et technologiques feraient bien d'être un peu plus rigoureux  : ils ne devraient pas tolérer l'emploi de tels mots, car il en va de la crédibilité du monde scientifique et,  aussi, de la crédibilité de leur journal.

D'ailleurs je me demande si cela ne vaudrait pas la peine de toujours signaler aux éditeurs l'erreur qu'ils font quand ils admettent des titres indus ?

Si l'on n'est pas entièrement charitable, on peut aussi penser que les éditeurs de ces journaux ne sont pas les scientifiques les meilleurs : bien souvent, ceux qui détournent de leur temps de recherche scientifique pour la participation à des comités éditoriaux... privent leur recherche scientifique de ce temps-là : ce ne sont pas les plus compétents, dirions-nous en litote.

Et quand le ver est dans le fruit...

jeudi 18 août 2022

I don't agree

I appreciate the research of George Whitesides, as far I can judge from his scientific articles, but I don't always agree with him.
In  Using Simplicity (The Analytical Scientist, 04/25/2014), he writes : 

"For more than five decades, I have worked in academic research. The questions I and my colleagues – graduate students, postdocs, and collaborators – addressed in the beginning were “academic”, meaning that they focused purely on curiosity."

For example, he writes "purely on curiosity". And I have the feeling that this is inappropriate. I shall comment on it later.

Then he adds  : "They were usually great fun, but often seemed a little other-worldly."

Here, I have the feeling that this is his point of view, with no generality.

Next sentence : 

"More recently, I have become interested in how best to make university research both intellectually interesting (that is, science for the sake of understanding) and practically useful (that is, technology that works)."

And here, it is clear that this is only his point of view. And if he is happy in the new way, all the best, but again, nothing general.
On the other hand, I observe that "for the sake of understanding" is different from "focused on curiosity", and I have to comment on "practically useful", as it misses one point, i.e. to recognize that sciences of nature don't have only applications in technique, but also in instruction (I don't use "education", because this would mean to teach politeness, social practices, etc.).

Finally (for this introduction), he quotes the "Pasteur quadrant"... forgetting that Pasteur himself recognized very clearly that the fruit is not the tree, on one hand, and also that he felt the obligation to move from science to technology (vaccines, serums, remedies to diseases of vinegar, wine, etc.).

About sciences of nature

First, let us observe that when "science" is discussed, in this context, it means "sciences of nature", not sciences of humans and of societies. 

Now, I propose that the goal of science is "exploring the mechanisms of phenomena". And Albert Einstein can be quoted: to lift a corner of the great veil, in other words to make discoveries.
This is not a question of curiosity, or "amusement of scientists", and I have the feeling that such a description is not fair: it is a symptom of the state of mind of Whitesides, not more.
Now, I also know that Whitesides was invited to write about his personal way, in this article, but strange enough, I prefer his work than some of his personal thoughts. Indeed, I prefer  the ideas of scientists such as Michael Faraday, or Albert Einstein, even if my ideas as slightly different, as one can see about my transformations of the talk given by Albert Einstein about Max Planck.

First the Einstein's text

Principles of Research, address by Albert Einstein (1918, Physical Society, Berlin, for Max Planck's sixtieth birthday)

In the temple of science are many mansions, and various indeed are they that dwell therein and the motives that have led them thither. Many take to science out of a joyful sense of superior intellectual power; science is their own special sport to which they look for vivid experience and the satisfaction of ambition; many others are to be found in the temple who have offered the products of their brains on this altar for purely utilitarian purposes. Were an angel of the Lord to come and drive all the people belonging to these two categories out of the temple, the assemblage would be seriously depleted, but there would still be some men, of both present and past times, left inside. Our Planck is one of them, and that is why we love him.

I am quite aware that we have just now lightheartedly expelled in imagination many excellent men who are largely, perhaps chiefly, responsible for the buildings of the temple of science; and in many cases our angel would find it a pretty ticklish job to decide. But of one thing I feel sure: if the types we have just expelled were the only types there were, the temple would never have come to be, any more than a forest can grow which consists of nothing but creepers. For these people any sphere of human activity will do, if it comes to a point; whether they become engineers, officers, tradesmen, or scientists depends on circumstances. Now let us have another look at those who have found favor with the angel. Most of them are somewhat odd, uncommunicative, solitary fellows, really less like each other, in spite of these common characteristics, than the hosts of the rejected. What has brought them to the temple? That is a difficult question and no single answer will cover it. To begin with, I believe with Schopenhauer that one of the strongest motives that leads men to art and science is escape from everyday life with its painful crudity and hopeless dreariness, from the fetters of one's own ever shifting desires. A finely tempered nature longs to escape from personal life into the world of objective perception and thought; this desire may be compared with the townsman's irresistible longing to escape from his noisy, cramped surroundings into the silence of high mountains, where the eye ranges freely through the still, pure air and fondly traces out the restful contours apparently built for eternity.

With this negative motive there goes a positive one. Man tries to make for himself in the fashion that suits him best a simplified and intelligible picture of the world; he then tries to some extent to substitute this cosmos of his for the world of experience, and thus to overcome it. This is what the painter, the poet, the speculative philosopher, and the natural scientist do, each in his own fashion. Each makes this cosmos and its construction the pivot of his emotional life, in order to find in this way the peace and security which he cannot find in tbe narrow whirlpool of personal experience.

What place does the theoretical physicist's picture of the world occupy among all these possible pictures? It demands the highest possible standard of rigorous precision in the description of relations, such as only the use of mathematical language can give. In regard to his subject matter, on the other hand, the physicist has to limit himself very severely: he must content himself with describing the most simple events which can be brought within the domain of our experience; all events of a more complex order are beyond the power of the human intellect to reconstruct with the subtle accuracy and logical perfection which the theoretical physicist demands. Supreme purity, clarity, and certainty at the cost of completeness. But what can be the attraction of getting to know such a tiny section of nature thoroughly, while one leaves everything subtler and more complex shyly and timidly alone? Does the product of such a modest effort deserve to be called by the proud name of a theory of the universe?

In my belief the name is justified; for the general laws on which the structure of theoretical physics is based claim to be valid for any natural phenomenon whatsoever. With them, it ought to be possible to arrive at the description, that is to say, the theory, of every natural process, including life, by means of pure deduction, if that process of deduction were not far beyond the capacity of the human intellect. The physicist's renunciation of completeness for his cosmos is therefore not a matter of fundamental principle.

The supreme task of the physicist is to arrive at those universal elementary laws from which the cosmos can be built up by pure deduction. There is no logical path to these laws; only intuition, resting on sympathetic understanding of experience, can reach them. In this methodological uncertainty, one might suppose that there were any number of possible systems of theoretical physics all equally well justified; and this opinion is no doubt correct, theoretically. But the development of physics has shown that at any given moment, out of all conceivable constructions, a single one has always proved itself decidedly superior to all the rest. Nobody who has really gone deeply into the matter will deny that in practice the world of phenomena uniquely determines the theoretical system, in spite of the fact that there is no logical bridge between phenomena and their theoretical principles; this is what Leibnitz described so happily as a "pre-established harmony." Physicists often accuse epistemologists of not paying sufficient attention to this fact. Here, it seems to me, lie the roots of the controversy carried on some years ago between Mach and Planck.

The longing to behold this pre-established harmony is the source of the inexhaustible patience and perseverance with which Planck has devoted himself, as we see, to the most general problems of our science, refusing to let himself be diverted to more grateful and more easily attained ends. I have often heard colleagues try to attribute this attitude of his to extraordinary will-power and discipline -- wrongly, in my opinion. The state of mind which enables a man to do work of this kind is akin to that of the religious worshiper or the lover; the daily effort comes from no deliberate intention or program, but straight from the heart. There he sits, our beloved Planck, and smiles inside himself at my childish playing-about with the lantern of Diogenes. Our affection for him needs no threadbare explanation. May the love of science continue to illumine his path in the future and lead him to the solution of the most important problem in present-day physics, which he has himself posed and done so much to solve. May he succeed in uniting quantum theory with electrodynamics and mechanics in a single logical system.

Let's move on to my vision; every word counts, every difference seems essential to me

Men and women have varied reasons for being in the Castle of Natural Sciences. Their motivations, their characters, their values, their morals are as diverse as outside, in the great world. One devotes himself or herself to these Sciences because he or she takes a marvelous pleasure in it... which he or she could always justify with all the more bad faith that he or she would be more intelligent; but those do not need to waste their time justifying themselves, because it is enough for them to be there, active, engaged, happy. For them, there is this happiness of the mechanisms of the world, like gears to infinity. Their quest is a sufficient sport, a lively world, overflowing with energy, the realization of all their dreams. Their commitment is "intrinsic".

But many others also meet in this Castle, and for these others, there is no shortage of extrinsic or concomitant motivations, rather than intrinsic ones! There are those who come here to rule, to lead (over others). There are those who come there to "make a living". Those who come there because there are people, light, heating...  There are those who like the difficulty of the scientific work. Those who have been driven there by their family, their environment...  There are also those who are there because why not there rather than elsewhere. There are those who are there because the hazards of life have led them there. There are those who are there because they are merchants. There are those who are there because they admire those who have an intrinsic interest in being there, and they would like to have, like them, a kind of naive faith in the Sciences of nature, which, by the way, can lead them to strive for it. And all the others.

If an angel of God were to appear and drive out of the Castle all the men and women who belong to all categories except the first, the Castle would be much emptied, but there would still be men and women of the past and present. Among these, we would find our Jean-Marie. That's why we love him.

I know well that, by his appearance, the angel would have chased away with a light heart many men and women of value, and even some who built the Castle of the Sciences of nature. For the angel, the decision to be made would be frighteningly difficult in many cases, especially since the Castle would not have been built without many of those who were excluded, just as a forest does not survive if it is made up only of trees!
But still, it must be admitted that many could have been satisfied with any theater for their activity. Circumstances could have decided differently on their career, and they could have worked as engineers, officers, merchants, sportsmen, directors, presidents...

Let's look at those who have found grace in the eyes of the angel. They are singular, sometimes solitary and difficult to recognize. How did they get to the Castle? It's hard to say, especially since the reasons are probably not the same for everyone. Albert Einstein and Arthur Schopenhauer proposed that one of the most powerful motivations that lead to an artistic or scientific work is the will to "escape from everyday life in its cruel rigor and despairing monotony, a need to escape the chains of eternally unstable desires". This would push sentient beings to free themselves from their personal existence to seek the universe of objective contemplation and understanding. This motivation would resemble the nostalgia that draws the city dweller away from his noisy and complicated environment to the peaceful landscapes of the high mountains, where the gaze wanders through a calm and pure atmosphere, and gets lost in the restful perspectives that seem to have been created for eternity.
Personally, I believe that the -negative- rejection of a "cruel", "hopeless", "monotonous" world is not a good explanation. Can we not, rather, imagine that the intrinsic interest for the Sciences of nature is the real motivation? Besides, the world is neither cruel, nor hopeless, nor monotonous... It is the world, and we see it as we construct our vision of it: it is up to us to see it as wonderful, perfectible, of infinite variety... It doesn't matter, because the question is not there: there is in the Sciences of nature, in their practice, second after second, an intrinsic pleasure... which is not extrinsic by definition. And this is why the angel would have so much difficulty!

Yes, those who remain in the Castle seek to form a simple and clear image of the world. Thus they overcome the world of experience because they strive, to a certain extent, to replace it with this image. But not to overcome it, but to add a level of vision. To the construction of this intellectual vision, and to its realization, they devote most of their life, focusing their energy, escaping from the swirling and subjective experience of the world.

All is said. Where would Whitesides be, in this context? For sure, for scientists such as Planck and Einstein, but also Faraday and others, "science has purpose beyond simply amusing scientists"  !

Is science out-worldly? No!

Let us now discuss this expression "out-wordly". Indeed, what does it mean? As a scientist, with lectures, with articles, with teachings (at the university or within the lab, with younger scientists), I have to be over-worldly, on the contrary!
Indeed, we scientists are as all other citizens, and we spent a lot of time in administration and in communication, so that the difficulty is indeed to protect our time of scientific activity. We have to apply to grants, to evaluate and be evaluated, to manage our budgets, to discuss with the suppliers, to manage the research team... Out-wordly, you said? No, certainly no.
Indeed, one could interpret what GW wrote: he was thinking of the old opposition of science and technology, with "useless" science and "useful technology".
But first, we should that that technique is useful, rather than technology  (I know that some confuse the two, but they should not: let's use the words correctly, not according to our owns definition). Then science is definitely useful, even practically, and I take the example of Einstein's relativity theory to show it: without it, the GPS couldn't have  been introduced. You see how useful it was! Indeed the question is of timing, and we could speak of immediate usefulness and delayed usefulness... except that "useful" is an adjective... and my proposal (and recommendation) is to always replace adjectives by the answer to the question "how much?".
How would you measure the usefulness of science to instruction, for example? Is it immediate (if taught at the university, immediately, as it has to be), or delayed? Let's be cautious when we make generalities, and  comparisons!

More positively

For me, thinking does not mean "saying no", but on the contrary "saying yes". Carefully, for sure, and not to any idea, but I want "yes", enthusiasm, wonderment...
I propose to think that science, technology, technique, instruction are at the same level, considering for example that a good technician is better than a bad scientist, that a good professor is better than a bad technologists, etc. For each of these activities, the issue is the personal fun that we found in it, and comparison is needed. If you want to do technique, do it; but if you are interested (a mild word, for me), then do science ! And don't forget this wonderful sentence in Alsatian "Mir isch was mir màcht" (we are what we do).

Les gâteaux au miel ne vieilliraient pas ?

 Les gâteaux au miel vieillissent-ils ? Je considère la question ici :

mercredi 17 août 2022

Un exemple pour bien expliquer ce qu'est la technologie

Un collègue me demande la différence entre les sciences de la nature et la technologie. Je lui explique d'abord formellement, en indiquant bien l'objectif de l'un et de l'autre : "lever un coin du grand voile", en explorant les mécanismes des phénomènes pour les sciences de la nature, et chercher des applications des connaissances scientifiques pour le second.

Mais il m'objecte que l'exploration technologique s'accompagne souvent d'un travail qu'il dit "scientifique", et je veux lui expliquer mieux la différence.

Dans un billet précéent, j'ai déjà considéré la table des matières d'une revue scientifique de "science et technologie des aliments" pour bien montrer la différence entre les articles scientifiques, très rare, et les articles technologiques, bien plus nombreux.
Pourquoi ceux qui font un travail technologique se raccrochent-ils souvent à l'étiquette "scientifique" de façon un peu indue ? Au fond, la technologie est merveilleuse, et, politiquement, nous aurions bien raison d'expliquer à nos jeunes amis qu'elle l'est, si nous voulons contribuer à nous entourer de technologues de talent, au lieu d'avoir des technologues frustrés de ne pas faire de science.
Et puis, c'est aussi une question d'honnêteté intellectuelle, ou de bonne compréhension du monde, de clarté.

Là, pour mieux me faire comprendre,  je viens de trouver un texte qui s'intitule  :
Texture formation of dehydrated yellow peach slices pretreated by osmotic dehydration with different sugars via cell wall pectin polymers modification
L'objectif du travail rapporté était de se préoccuper de la consistance  de rondelles de pêche qui avaient été déshydratées à l'aide de divers sucres.
La déshydratation des pêches ? Une question technique (du grec techne, qui signifie "faire"). Et l'amélioration des techniques de déshydratation ? Une question technologique.

Les auteurs de l'article ont déterminé les différences dues à l'emploi de divers sucres (une caractérisation, donc), ce qui est manifestement un travail technologique : il s'agit de déshydrater des pêches, et pas de chercher des connaissances nouvelles.

Evidemment, lors de leur travail, les auteurs  ne se sont pas contentés d'observer les effets différents obtenus à l'aide de sucres différents, et ils ont  cherché à comprendre ces différences. On pourrait dire qu'ils ont "découvert" des effets différents de sucres différents, et qu'ils ont cherché à comprendre ces résultats différents. N'est-ce pas de la "science" ?

Non, car le but n'était pas de trouver des mécanismes nouveaux : nos collègues ont utilisé des connaissances classiques pour faire ce travail ; ils n'ont pas trouvé d'objet nouveau du monde (pensons aux fullérènes, à la compréhension de la décohérence quantique, etc.), ils n'ont pas introduit de concept nouveau (pensons au potentiel chimique, à l'entropie, etc.).
Bref, leur intention était de comprendre un effet à l'aide de connaissances classiques, et pas de rénover les connaissances.

C'était de la bonne technologie ; pas des sciences de la nature.