Roughly speaking, it is at the end of my chemistry PhD (defended in December 2006) that epistemological questions about the ‘basic equation’ of chemical kinetics led me to study the history and philosophy of science quite seriously. This ‘basic equation’ is of course the rate law, which governs the rates of chemical reactions (translation note: in the francophony, this law is called van ‘t Hoff law, the same name as the law governing the equilibrium constant! But apparently, in English-spoken countries, it holds only for the second case).  Why these questions?… Simply because the results of my doctoral works led me to this! Some explanations are required here.

I used a polymerization process, called RAFT polymerization, extensively during my PhD work. The RAFT process is a special type of radical chain polymerization: without an additional component that is added to perform RAFT polymerization, it is a ‘conventional’ polymerization. The synthesis of this type of additional component – which is called a ‘chain transfer agent’ – was a significant part of my PhD works. But it turns out that no one really understands why the polymerization rate is (mostly) slower during a RAFT polymerization compared to a conventional one: if we apply the rate law to the known mechanism of a RAFT polymerization, we end up with the same equation as during a conventional polymerization: basically, as chemical equilibriums are set up, there are many terms that are simplified and we end up with the ‘classical’ equation.
Personally I found it a bit strange not to find any record of the complex mechanism of RAFT in the final result, because it was against my ‘intuitive’ understanding of the process; But as one should of course be suspicious (very often) of the primary intuition in science, I did not initially consider this minor annoyance. In short, in theory it is supposed to go as fast as a conventional polymerization, but in practice we can see that a RAFT polymerization is (often) much slower! This is called a ‘retardation phenomenon’. Between 2000 and 2006, two research teams were fighting for resolving this phenomenon, each giving their possible explanation by modifying the reaction mechanism (or by constraining some of the rate constants): two relatively different hypotheses were then in place.
But by repeatedly encountering experimental results that did not support either one of the hypotheses or the other, a weak consensus was reached in the polymer science community since 2006: it was probably necessary to consider the conjunction of both hypotheses at the same time in order to understand the retardation phenomenon.

However, on my side, without being initially interested in the kinetics of RAFT polymerization, I was confronted during my PhD work (at the end of 2005) with even slower RAFT polymerization rates (in comparison with a so-called ‘classical’ RAFT… therefore already slower than a conventional polymerization)! It is by trying to understand this ‘over-retardation’ phenomenon that I entered the debate by presenting a poster in an international conference (poster on the top right of this page) and then by publishing the corresponding article in a scientific journal. What is not explicitly stated in these two publications is the fact that these results challenge, according to me, the weak consensus of the moment (but it is written quite clearly in my thesis manuscript on pages 158 and 159). In short, according to me, we don’t even have the beginning of an explanation for the retardation phenomenon!
As I have confidence in the competence of my peers in the discipline, but as they have been trying for 6 years to modify (on somewhat in all directions) the mechanism of RAFT polymerization without obtaining any convincing result in the end, I considered that I should explore another direction. And here I was wondering, which I didn’t know yet to be, in a certain sense, a heretic question (with respect to what I would learn to be the paradigm of polymer science): is the rate law really suitable to describe the RAFT process? … and to continue logically on the following question: but by the way, where does this law come from? These are probably the first epistemological questions that I really seriously considered in my research activity … even before I knew what epistemology was and that this particular scientific field existed!

After a few brief searches on the internet, here I am at the library of the University Lyon 1 looking for a copy of “Etudes de dynamique chimique” by Jacobus Henricus van ‘t Hoff published in 1884. In short, it is a very old law and it appears that J.H. van ‘t Hoff received the first Nobel Prize in Chemistry in 1901 for (among other things) this work. Nevertheless, both this ancientness and this award do not prevent the totally empirical character of van ‘t Hoff’s kinetic law. The basic principle of an empirical law is that it works as long as it works… but the time when it does not seem to accurately describe an atypical phenomenon, it is then legitimate to wonder if we have not gone beyond the field of validity of this law (and therefore it is also legitimate to try to find another one more appropriate to this `resistant’ phenomenon). The small problem is that one never learns during the training of a chemist either the empirical character of van ‘t Hoff’s law, or the epistemological limits of an empirical equation. Personally, a little interest of mine for philosophy since the final year of high school made that I was a bit familiar with some notions of philosophy of sciences (by some self-educated readings, but also having attended a small module of history and philosophy of sciences proposed by my doctoral school). For the funny story, the sentence highlighted at the bottom of the page of this web site was already in epigraph of my thesis manuscript.
Furthermore, I had been surprised in the original works of J.H. van ‘t Hoff by the absence of definition of the proportionality constants in the presentation of his law (the famous ‘velocity constants’, usually noted k_x). This is not necessarily surprising for an empirical equation, but it revealed the author’s lack of interest in giving a real chemical/physical meaning to these k_x rate constants: they were just proportionality constants linking the reaction rate to the concentrations of reactants, and that’s all. I must admit that I was somewhat disappointed by this finding.

I then tried to give some physical meaning to these rate constants in the specific case of radical polymerization. Combining this research with a very personal and ‘intuitive’ understanding of the RAFT polymerization mechanism, I then proposed a new chemical kinetics equation for chain reactions: it turns out that van ‘t Hoff’s law becomes a perfect approximation of this new equation in the case of a conventional polymerization, but in the case of a RAFT polymerization there are additional terms that are not negligible. I then compare this equation to the experimental kinetic data of the literature… and it works really well ! Very confident, as I am in the period of writing my thesis manuscript, I write an appendix of about twenty pages where I try (rather awkwardly I must admit with the retrospect of years) to explain my approach and the use of the new kinetic law to better understand the RAFT process. In this appendix, I perform (without knowing it at the time) what should not be done if one wants to stay in the paradigm of the polymerists (in the sense given by Thomas Kuhn): I quote the initial work of J.H. van’t Hoff (whereas one usually limits oneself to a maximum of 10-15 years of age in the bibliography), I make a reminder about the strict mathematical definition of what is the integration of a mathematical equation (and most polymerists are not really ‘math geeks’), and I even evoke Zeno’s Paradoxes by quoting a philosopher, Henri Bergson. And so here it gets tricky!
First of all, I must emphasize the humility of my PhD supervisors, who felt overwhelmed by my somewhat complicated thinking on chemical kinetics equations, and considered themselves incompetent to judge the scientific quality of the content of this appendix. This was quite normal for polymerists specialized in the synthesis of complex macromolecular architectures, but not particularly interested in the problems of chemical kinetics. But then, they deferred this task to the referees of my PhD committee by choosing experts (of course from the same field, because the quality of the 280 other pages of the manuscript had to be evaluated as well) having a little more interest in the problem of kinetics of RAFT polymerization. So I send my PhD manuscript containing this appendix to the referees. And there, it is the drama!
I’ll give you the short story here, avoiding the epistemological aberrations that I heard: it simply ended at the jury’s deliberation during my PhD defense with my obligation to withdraw the appendix, highly problematic in their opinion, in the final version of my PhD manuscript (which, apart from the appendix, had nevertheless been considered as an excellent work)! The only sign of the initial presence of this appendix that remains in this final version is the identical last sentence on pages 159 and 222 (initially followed by a reference to the appendix).
In short, without knowing it, I was presenting a modest work of critical epistemology (concerning the sub-discipline of ‘chemical kinetics’) to polymerist researchers, who were obviously very skilled in their field of expertise, but who had never been trained (neither from afar nor closely) in epistemology: so inevitably, it could only end in mutual misunderstanding. Of course, I didn’t convince anyone of the plausibility of my results, but it was the same the other way around: no one was able to show me how my inquiry process was not legitimate and/or was flawed. So, I didn’t give up…

Since the new equation I was proposing was finally as empirical as van ‘t Hoff’s law, it was an idea to try to find a physical justification for it that was much more robust than my few intuitions and epistemological considerations that I had presented in the withdrawn appendix. Of course, I checked beforehand that there was no physical justification for van ‘t Hoff’s law, but the bibliographical research I was doing at the time only brought me to works concerning the physical justification of another important law of chemical kinetics, Arrhenius’ law (I must admit, however, that this is a bibliographical search that I should perhaps pursue again in order to confirm this absence of works concerning van ‘t Hoff’s law).
As the driving force of all chemical reactions is the thermal agitation of molecules, I began a small historical and epistemological investigation of our knowledge of this phenomenon. It turns out that the phenomenon of thermal agitation is intimately connected to the final acceptance of the atomic idea at the very beginning of the 20th century (notably the work of Jean Perrin in 1908). And here I am, very quickly, diverging towards the history of the contemporary atomic model and that of the early development of quantum theory (notably the pioneering works of Planck and Einstein). In short, I moved from chemistry to the history and epistemology of physics.
At the same time, I notice that the existence of the phenomenon of thermal agitation, which seems to indicate that there is no immobility at the microscopic scale, contradicts the conclusion that Zeno of Elea would like to reach by proposing these famous ” Motion Paradoxes ” (i.e. that motion would only be an illusion). In short, I started to be very interested in these “Paradoxes”, and therefore incidentally also in the notions of rest vs. motion. By accident, these two notions are fundamental in other works of a scientist already mentioned above; so even if I read Einstein for his contribution to the quantum theory, here I am also reading him for his elaboration of the special relativity theory. Of course, this also implies to be interested in the principle of relativity stated by Galileo. In brief, I’m still in full physics with all this!

And this is how I went from a problem of polymerization kinetics that appeared at the very beginning of the 21th century to the history (at the end of the 19th and the beginning of the 20th century) of the two pillars of modern fundamental physics. As I hope to do a serious job, I first focused on the oldest philosophical problem whose resolution (or rather non-resolution in this case!) determines, it seems to me, the framework of thought in which all physical theories were then built: how to conceptualize the passage from immobility to motion? This problem is at the very heart of Zeno’s famous ” Motion Paradoxes “. So I started with it, but my work on this subject is really not an end in itself… it is only the beginning of the challenge…

Source (before modification) of the article’s illustration image: http://wise.ssl.berkeley.edu/gallery_thesky.html
Other sources of the illustration images: https://commons.wikimedia.org/wiki/File:Vant_Hoff.jpg ; https://commons.wikimedia.org/wiki/File:Henri_Bergson_(Nobel).jpg

First, make ‘fictional’ epistemology in order to propose, in a second time, new unexpected basics for fundamental/theoretical physics.

In a little more detail:

My current research project in epistemology is based on the following working hypothesis:

Could the problems encountered by current fundamental/theoretical physics have their origin in implicit (or ‘forgotten’) assumptions accepted from the very beginning of the construction of our modern theories?

The problems in question are the ‘big’ problems of physics, i.e. the lack of a ‘realistic’ interpretation of quantum theory, incompatibility between general relativity and quantum physics, the nature of dark matter, the nature of dark energy, etc….

It is therefore in some way doing a split between the current concerns of theoretical physicists and those of epistemologists and science historians.

This naturally leads to a strong interest in the history of science of the end of the 19th and the beginning of the 20th century, a period during which the two main theoretical cornerstones of present-day physics were born: the theory of general relativity (TGR) on the one hand, and the ‘quantum theory’ on the other. It should be noted that another important element of modern physics, the theory of special relativity (TSR), is common to these two cornerstones: for the first one, the notion of space-time (‘mathematically’ constructed by H. Minkowski, but resulting from the works of H. Lorentz and A. Einstein) is essential to TGR; as for the second, the standard model of particle physics (one of the sub-domains of ‘quantum theory’) has for example incorporated TSR through the presence of antiparticles (via the Dirac equation).

However, my approach is really not that of a science historian since I re-examine the construction of past knowledge with the help of current knowledge: I therefore use anachronism (the sin of a true historian!) as a heuristic tool to try to perceive implicit foundations of physical theories, i.e. hypotheses never really formulated (or never highlighted) but logically necessary for their global consistency.

A work of ‘classical’ epistemology is normally respectful of the historical context in which a knowledge/theory was built (thus avoiding for example anachronisms such as interpreting an experiment with notions that appeared later); it is therefore a ‘realistic’ epistemology: one tries to put oneself in the place of the scientist in his time in order to understand, for example, how he interpreted such and such an experiment or proposed such and such a theory. Now, in many cases, the interpretation of an experiment (or the choice of the fundamental notions of a theory) could have been confronted with several logical possibilities; thus the choice among these possibilities is then often constrained by several parameters: scientific context, historical context, sociological context, psychology of the scientist, etc., and it is precisely the role of the historian of science to try to evaluate the importance of each of these parameters. By remaining faithful to historical contexts, one can therefore potentially reconstruct the way of thinking of scientists in order to arrive at exactly the same results as they did: one thus understands how and why such knowledge was constructed, which is the very purpose of the history of science and epistemology.  Conversely, if one deliberately mobilizes current knowledge to interpret historical experiences or to judge the relevance of a theoretical choice of the past, one certainly has little chance of understanding the previous scientists, but it is sometimes possible to reach interpretations/conclusions different from those proposed (and/or accepted and/or validated) until then.  This is doing what we could call ‘fictional’ epistemology: if a particular scientist of a certain period had access to part of our current knowledge, what might have changed in the continuation of these experiments/theories? In short, it can give new ideas for the understanding of the physical world; this is the heuristic dimension of the exercise. It is in a way hijacking the goal of a classical epistemology in favor of theoretical physics (in the sense of bringing new concepts that can be potentially mobilized in the construction of innovative theoretical frameworks).

It should be noted that this exercise in ‘fictional’ epistemology does not necessarily involve real anachronisms: one can also play with the non-knowledge or non-taking into account, whether voluntary or not, on behalf of a scientist (or a community of researchers) of elements of knowledge produced by other scientists and/or other disciplines, even though they are from the same period. A typical example might be the interpretation of an experiment that is presented by the experimenter as the discovery of a particular phenomenon or entity, whereas from a purely epistemological point of view, it cannot be an ultimate proof (according to the principle of ‘under-determination of theories by data’) but is only the refutation of an adverse hypothesis. This ‘discovery’ then passes into posterity only because of the lack of imagination of other researchers (contemporaries of the experiment or later) who do not suggest other hypotheses that are not compatible with this ‘discovery’ but remain in agreement with the experiment (then wrongly called ‘crucial’). A concrete example is perhaps the ‘discovery’ of the electron by J.J. Thomson in 1897. Indeed, among the ‘new unexpected basics’ mentioned above, there is in particular the possibility of understanding the physical world without the concept of electron!

My publishing method

My first publication (Foundations of Science 2018) as part of this research project deals with the Zeno’s paradoxes of motion. This subject may seem very different from the concerns described above. However, it is the same approach: it is to consider the question (which may indeed seem absurd) “What if Zeno had known about the existence of thermal agitation, what would it change in his argumentation ?  ». The consequence of such a ‘bizarre’ hypothesis is to have been able to find what has been lacking for 25 centuries, namely a logical solution to these famous paradoxes. This solution consists in rejecting the notion of immobility as being relevant to describe reality. I have the impression that this simple result can change the game both at a philosophical and scientific level: it is the aim of my future works and articles to make this impression more practical.

This research project may seem rather heterodox, but my ‘strategy’ for sharing my ideas remains that of a ‘normal’ academic researcher: I write articles that I submit to philosophical/scientific journals; either it is accepted for publication and is then announced on this website, or it is rejected with the hope of getting constructive criticism from the reviewers in order to improve the article (and then submit it in another journal again). My first publication (Foundations of Science 2018) is for example the result of three review processes (and the final published version is quite different from the first submitted version; thanks to the six anonymous reviewers for their constructive contributions). In short, I do not wish to reveal all my research tracks on this site before peer review.

In particular, I already have some quite precise ideas about a new theoretical framework that seems promising enough to solve the ‘big’ problems of physics. These ideas came to me partly after the observation of some epistemological weaknesses in current theories. Because I do not wish to reproduce the errors of some previous scientific approaches, this new theoretical framework will probably only be released once I am sure that the philosophical (or even metaphysical) foundations that underlie it are robust. Thus, my current work in philosophy of science is a way of preparing the foundations for a more ambitious (but perhaps even too ambitious!) scientific framework. In this sense, I defend a natural continuity between the disciplinary field of philosophy (of science) and that of fundamental/theoretical physics, which does not seem to me to be too much the case in the current organization of research.

Source (before modification) of illustration image: http://wise.ssl.berkeley.edu/gallery_thesky.html