Jargonium poses its questions to philosopher of chemistry Hinne Hettema who has worked extensively on the question of chemistry's reducibility.
1. How did you get into the history and/or philosophy of chemistry?
I ended up in philosophy of chemistry through a series of circumstances; it was not by design. It was determined as much by a confluence of divergent interests as well as a certain amount of ‘gut feel’. After high school, I decided to go and study chemistry in Groningen because I liked the subject, the atmosphere of the department, and the intellectual challenge.
I did my ‘kandidaats’ exam (roughly a bachelor’s) in chemistry in March 1984 and at that point considered doing a double major for the remainder of my time. It turned out that the philosophy department was offering a program for people who had a bachelor’s in some (any) other subject and offered them the opportunity to complete a second master’s alongside their original field of study. If I remember correctly, the assumption was that you would continue with your other studies too. That fit exactly with my plans, and naturally set me up for ‘philosophy of chemistry’, although the field as such didn’t really exist at the time.
Groningen in the 1980s was an interesting place to be, and, with the benefit of hindsight, was leading the world in many areas. Luckily for me, both the chemistry and the philosophy department were part of that. I worked mostly with Theo Kuipers on philosophy of science and Wim Nieuwpoort in theoretical chemistry. What I discovered was that while I was not an organic chemist, I loved the little diagrams they made of things (especially molecular cages for some reason), sort of liked theories and models, enjoyed programming and computers, and wanted to know more about how one can use ‘just enough formalism’ to answer interesting questions, such as for instance approaches to the truth and how that impacts the sequencing of scientific theories.
Some of that ‘just enough formalism’ I still do–at the moment I’m very focused professionally on how to apply data science concepts and modelling to cybersecurity problems and identifying events before they become problems. It’s called the ‘left of boom’ approach, or ‘threat oriented defense’. It also helps us to get a handle on the quantity called ‘risk’.
All of that together more or less put me in the theoretical chemistry basket, also because fitting two non-conformant schedules of two geographically separate departments (inner city versus outskirts) together did not allow for long-running or fickle lab experiments to determine my timelines. Theoretical chemistry was the only chemistry one could do whenever wherever. I liked quantum mechanics, but now also wish I’d done more work in molecular dynamics and statistical mechanics when I had the chance.
Due to sheer luck, I spent an hour on my own with Peter Atkins when he was visiting Groningen. I was asked to talk to him because of a gap in his schedule and a shared interest in philosophy. I don’t think we talked much about philosophy, at least nothing I still remember now. I really wanted to know how he came to write the first edition of his textbook on Physical Chemistry. I got that answer, but don’t think it is correct to share it here.
I got my chemistry degree in March 1987 and my philosophy one on 31 August 1988. By some crazy coincidences I had three philosophy publications in the works upon graduation: a book review, a conference presentation which made it to the proceedings and a joint article with Theo in Erkenntnis.
After 1988 I went to Nijmegen to complete my PhD in theoretical chemistry with Paul Wormer on open shell and MBPT approaches to frequency dependent polarisabilities. I also spent about a year in Aarhus with Poul Jorgensen to work on the hyperpolarisability code for the Sirius MCSCF program (it’s now called Dalton: https://www.daltonprogram.org). With that latter work, in 1990 there was a certain amount of uncertainty whether that could be done at all. Poul had published, with Jeppe Olsen, a paper in 1985 that had a lot of the abstract formulas, but there was no implementation beyond linear response functions. I spent three months with pen and paper and worked out the technical programming aspects of that problem. Then we went and did it, initially on an Alliant, and then we got the RS6000 in Nijmegen, which sped things up quite considerably. Fortunately, around that time, operating systems started to converge on Unix, which made skills a lot more portable.
With Paul Wormer, I reworked the existing code for MBPT frequency dependent polarisabilities to the point where calculations at that level of precision could be done routinely. We essentially traded memory for execution time, making the most of the ‘obscene’ (if I remember correctly) 32MB of memory we had in the RS6000. I’m still happy to be one of the relatively few theoretical chemists who have had real impact on the code people still use today, having code in the Dalton program as well as the asymptotic components of the SAPT program. Both programs are still in use today.
I think theoretical chemistry needs to work harder as a discipline to regain that focus on novelty, As a happy outsider, I feel that academia has become overly risk averse. With that, I think we’ve seen the locus of innovation shift to the private sector, especially once the internet became a phenomenon. At some point, as a society, we’ll have to pay for that.
Then I spent 18 months at JHU in the US working in the Yarkony group on conical intersections and eventually ended up in New Zealand where I also ended my academic career and started working in IT and security.
I completed my philosophy PhD in the shed in my garden in my spare time between 2007 and 2012, more or less starting from our 1988 Erkenntnis article and Eric Scerri’s 1997 critique on it. Of all the philosophy work that I’d done, philosophy of chemistry was the one that got some traction. The result was published in 2012 as my thesis, and in 2017 by Springer in a shortened form called ‘The Union of Chemistry and Physics’. I came to the conclusion that there is a reductive and explanatory relationship between chemistry and physics, but that one needs to be pretty careful characterizing it. This relationship is accompanied by a rich ontology and is certainly not eliminative. It is good to see that the tide of anti-reductionism has turned, but it leaves us with interesting questions that I think we’re slow in answering.
2. What is your favourite question in the history and/or philosophy of chemistry?
I think we’re generally not paying enough attention to chemical ontology. We’ve let the metaphysicians run away with that topic in academic philosophy, and the field of ‘pure’ metaphysics is very specialized and small and has an essentialist orientation. In that way we have impoverished the field somewhat.
I strongly believe that the correct approach to ontology is existential quantification, and from there it follows that what there ‘is’ in this world is a series of ontological commitments to the things that appear in the theories we have but also in the stories we tell. I cannot make sense of the concept of ‘ontology’ without existential quantification, and that makes the world a rich place.
For me, having a perspective from computers and cybersecurity helps–we have many, many concepts in cybersecurity that are only getting flushed out through actual experience and shared stories, and that may shift very rapidly. Ontology is an evolving thing in cyber and a lot of the work in cyber and data science is setting up ontologies. Attackers are the ultimate innovators and sowers of confusion, and I see some of my day job as a philosophical laboratory with an incredibly compressed timeline. That can be tiring too, because you can never stand still.
Back to chemistry, which I think has a much richer ontology than our philosophical ontologists generally allow–one that is ‘essential’ in a non-reductionist (to physics) sense but also relational. And that is only true for those areas in chemistry where we have theories. And if you think about it, we only have ‘theories’ in the traditional sense in about half of chemistry. If you look at research in organic synthesis or biochemistry, for instance, we don’t have theories, we have processes, recipes and mechanisms. Looking at the ontology of recipes would be very interesting. And it is possible that work done in that area will force us to rethink the concept of scientific laws.
I also think the ontology question is strongly related to the reduction question, although, for me, ‘existential quantification’ in ontology does not allow for ontological reduction. I differ there, I believe, from Olimpia Lombardi, but quite frankly I don’t understand the whole idea of ‘ontological reduction’ and reading more about it doesn’t make things better for me. At an intuitive level, maybe, yes–stuff is stuff–but at the level of things it no longer adds up. I arrived at a Kantian notion of things, in which there is no scrutable ‘essence’ as such, but a set of relationships and functions.
From my perspective, ‘reduction’ can only happen once we connect theories or stories, and then whatever ontology happens is a result of that, but not something standing on its own. The world is diverse and rich. For me, theory reduction is the only allowable mechanism for reduction if we want to remain scientifically robust. From an ontological perspective, we end up with something like ‘encapsulation’ as we have in object-oriented programming, where certain things are just abstracted away from view, and may or may not have causal efficacy.
Interestingly, that ‘hiding’ does not need to be, and in chemistry certainly isn’t, strongly consistent. And this takes me to another topic that I think needs more attention: the logic we use to discuss reduction. We know at this point that a strictly interpreted reductionist model based on identities and strong consequence relations (roughly using a form of propositional logic) is not adequate to describe how physics and chemistry connect, but we have not yet done the work to employ other logics that may do the trick.
I think I’ve made a start by couching the whole thing in a Sneedian framework. Models take you away from strict identities, and rather encourage a modal way of thinking. Alternatives will also exist in para consistent logic or Priest’s ‘chunk and permeate’ approach. I think a lot more can be got from analysing the use of non-classical logics in reduction and philosophy of chemistry has every reason to be at the forefront of that. The likely outcome is in my view that some of these logics will fit, and as approaches can stand side by side. If we can do that well, logicians may even learn a new thing or two.
3. What is the value of history and/or philosophy of chemistry?
The value is asking new questions about the sort of science that chemistry really is. I don’t think that sort of questioning opens up new scientific questions in chemistry per se (although it may, but that would be very rare in my view; scientists usually do a pretty good job of pushing the boundaries), but it will help with fitting these new developments into a broader perspective and articulate how they fit in the whole fabric.
It also allows us to explore the boundaries and relationships of chemistry–to biology, medicine, physics and industrial processing. I think these boundary questions help us articulate better what chemistry is and help us to work out a consistency in approach, as well as interesting differences. So far, we’ve overly focused on the boundary to physics, but I think that potentially the boundary to biology may be richer.
I think chemistry is special in that chemistry is the simplest science in which we have very rich complexities, and it is possible that the boundary between ergodic and non-ergodic systems runs right through the middle of the field. If that is true, then I think chemistry is the lowest level (in terms of the complexity of the basic building blocks) at which some of the thinking that we need to understand complexity, path dependence and constraints, all key concepts in modern systems thinking, occurs. Chemistry is a beautiful pivot point between physics and its fundamental laws and the complex richness of biology and complex systems. From that perspective, its philosophy is immensely valuable, and also relatively underdeveloped.
We may have an early indication for the truth of this contention in the research of protein folding. From first principles protein folding is an immensely complex problem, which I think is also unsolved. But when train an AI on existing protein structures we start getting decent predictive protein structures starting with nothing more than protein sequences (https://deepmind.google/technologies/alphafold/).
4. What are you currently working on?
I am writing a book about the philosophy of cybersecurity and progress is incredibly slow, because the field develops so fast. My publisher is fortunately very patient, and they’ll have to be.
I’m also, through my paid work, looking in depth at Dave Snowden’s work around Cynefin and Estuarine mapping as well as constraint theory and path dependence (because it helps cybersecurity problems) but the underlying science and philosophy there is, I think, very relevant for philosophy of chemistry too (more at No. 6 below).
I’m opportunistic in my philosophical work–if I see a problem I think I can contribute to in a new way I’ll write a paper, otherwise I leave it be.
Some people in the field know I’ve said ‘no’ to some opportunities in philosophy of chemistry, and that is because at the time I felt I had said what I wanted to say in the way I wanted to say it and had no desire to add something more to it. Maybe I will write some more papers in the future, maybe not.
5. How do you envision the future of the field? What are the areas/topics that you believe deserve more attention?
I am optimistic about the intellectual future of philosophy of chemistry and believe we’re only starting to scratch the surface. There are tremendous opportunities and unexplored questions.
From my outsider perspective, I am pessimistic about the future of philosophy of chemistry in academia. The field has never obtained a solid foothold when times were good, and times in academia are about to get much, much worse. There is some evidence that when funds are reduced, as they surely already are and further will be, organizations tend to ossify into the structures that already exist. That’s because of defensiveness, sunk cost fallacies and the fact that well-trodden paths are easier to traverse. When times are difficult, humans tend to do more of what is failing us. Philosophy of chemistry in my opinion does not have enough of a foothold to broadly survive that situation in its current form.
To make the most of the intellectual opportunities open to us, as a discipline we have to learn to survive outside the academic world, or perhaps be only half in it. We should not aim to structure the field as a traditional academic discipline, but as something that can stand on its own wherever it happens to be. If that hunch is correct, we also have to consider how we can maintain our quality mechanisms and how we can broaden the appeal to current outsiders that have a legitimate role to play. Not easy questions, but things that I believe can be solved.
It is obvious to me that ‘online’ offers good opportunities, but we’ll have to consider what works and what doesn’t. From humanity’s early experiences in social media, we now know that a ‘marketplace of ideas’ is not a good model to be operating on. Organizationally, it is possible that Steve Wolfram’s ‘physics project’ offers us a template to work from (https://wolframphysics.org/).
Philosophy can learn from cyber there. It is easy to go to an online cyber conference, and it is hard to go to an online philosophy conference.
6. A recently published paper or book that you would recommend reading?
Anything Stuart Kauffman has written about the adjacent possible is I think a starting point for fleshing out some of the more interesting ontological questions in philosophy of chemistry. The idea that there is a state space of adjacent possibles (with a corresponding thermodynamics) is just fascinating, and I think highly relevant to us (https://arxiv.org/pdf/2204.14115.pdf). Similarly, the idea that the world above 500 Daltons is largely non-ergodic (https://mitpressbookstore.mit.edu/book/9780190871338 and https://arxiv.org/pdf/2106.15271v4.pdf) has huge consequences for how we think about chemistry (most chemistry of biological importance would be non-ergodic in that case, and the ergodic / non-ergodic dividing line runs somewhere right through the middle of chemistry). As Kauffman writes, the world ‘is not ergodic with respect to complex molecules.’ (p. 4 of ‘A world beyond physics’).
We should be very aware that if all that is true–and I think there might be experiments there that we might be able to do–then any biologically interesting chemistry is strongly emergent. As philosophers of chemistry, we may have to come to grips with that reality. Since I’m a believer in existential quantification as the road to ontology, I do not find the idea of strong emergence intuitively problematic, but I also think I’m in the minority there.
Alicia Guerrero’s book on how constraints create coherence (https://mitpress.mit.edu/9780262545662/context-changes-everything/) has, I think a few key concepts for how we think about those pieces of chemistry that are not, strictly speaking, theoretical. Similarly, any ontology of processes or recipes will need to consider the concept of path dependence, which would be a new idea for philosophy of chemistry, and also an area where philosophy of chemistry leads the way.
A lot of this also has feedback loops to the work Ilya Prigogine did in the 1960s through to the 1980s on non-equilibrium thermodynamics, although I think the book he wrote at the time with Isabelle Stengers (https://www.penguinrandomhouse.com/books/643445/order-out-of-chaos-by-ilya-prigogine-and-isabelle-stengers/) is a bit too non-specific about the problems and potential solutions. His technical work is much better, but one would have to look anew with the eye of the philosopher to determine what was really going on there. A lot of the 1980s popular work is tainted with ‘new ageism’ and from both a philosophical as well as a scientific perspective, just sheer tendentious nonsense.
All this would also allow philosophy of chemistry to explore its other boundary–that with biology and medicine–in more detail. I think we’ll get unique perspectives from that, and integrating those perspectives back into all the work we’ve already done around chemistry’s boundary to physics will help us flesh out what chemistry’s unique relation is to the world.
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