Marie Gueguen is an alumnus of the Rotman Institute, who completed her doctorate under the supervision of Chris Smeenk in 2019. She was recently awarded a Marie Skłodowska-Curie Actions (MSCA) Individual Fellowship (IF) grant by the European Commission. Her unique project will embed her in a research group working with molecular physicists and astrochemists–one of the first ever collaborations between a philosopher & scientists working in France. We asked Marie to complete this brief interview with us to tell us about a bit more about the exciting research she’ll be conducting & what she hopes to achieve with this innovative project.

First, congratulations on the Marie Curie Fellowship you’ve just been awarded! Your project is titled, “Taming the Uncertainty Monster: Lessons from Astrochemistry (TUMLA)’’. What will be the focus of this project & what are you hoping to learn?

Thank you!  I am especially thrilled to have been awarded this fellowship as it is the result of a common effort between molecular physicists, chemists and philosophers willing to work together in order to promote philosophy of science and to advance the field of astrochemistry. Astrochemistry is a young discipline, which started with the detection of molecules in the interstellar medium –the medium where stars are born– in the 1940’s, even though such an environment, with low temperatures, low densities, constant exposure to radiation and to cosmic rays had been considered too hostile to host molecules, even more so the complex organic molecules that have since been discovered there. In this field, models based on extrapolated data containing a lot of sources of uncertainties, fail to reproduce observations. Observations, on the other hand, are known to be both incomplete and uncertain. Yet, models are indispensable to take the most of observations, making it possible to better target future campaign observations; to determine where better experimental data are needed; and also to motivate further theoretical developments. Thus, astrochemists have no choice but to develop methods to evaluate their models and decide how the disagreement between the observations and the model should be interpreted, i.e., how this disagreement must guide their future work. As a philosopher, I will be working on analyzing and assessing the trustworthiness of these methods based on a very innovative use of sensitivity analysis coupled with more traditional uncertainty propagation methods, and more generally by contributing to building an account of the adequacy of models that takes into account the challenging difficulties that high-uncertainty contexts such as astrochemistry face.

The second aim of the project is to appeal to philosophy of science to facilitate the interdisciplinary work between experimentalists, theoreticians and modelers. The existence of molecules in such a hostile environment has openedbrand new perspectives both for chemistry and for astrophysics. Chemistry has much to learn from molecular behavior in these extreme, low-temperature conditions. From the perspective of astrophysics, the presence of molecules offers a formidable window into the physical conditions at play in the interstellar medium: indeed, molecules can be used to diagnose the physical conditions of their environment, given their dependence upon physical properties such as the density, temperature and radiation of the molecular clouds. But taking the most of astrochemistry requires for experimentalists, who cannot reproduce in their laboratory the temperature and pressure conditions of the ISM; theoreticians proceeding to calculate reaction rates with a very high degree of precision on systems of very small size –i.e., often up to three atoms; and modelers having to design chemical models involving hundreds of molecules and thousands of reactions to work together. My role in this project is to facilitate this interdisciplinary work to hopefully contributing to advancing the field of astrochemistry.

Your project team will include physicists from the Institute of Physics de Rennes 1 (IPR). Tell us a bit about the collaborators who will be working with you. Will this be their first time engaging with philosophers?

I will be joining the research group of Pr. François Lique, a group  composed of 8 Master, PhD and postdoctoral students working in the field of molecular physics and astrochemistry. Belonging to this group and working with them on a daily basis will allow me to better understand the interdisciplinary challenges they face and how philosophical tools can help overcoming them, and in return to introduce them to philosophy of science, to which they have never been exposed so far. François is a world leader in the field of molecular astrophysics, whose research focuses on the very accurate molecular data that astronomers and experimentalists need to make the most of very high-resolution observations and experiments. He will introduce me to the way in which the work of theoretical chemists, astronomers, astrophysicists, and laboratory chemists must enter the modelling of chemical processes of astrophysical interests, how models are developed when key observations are lacking, and how models disagreeing with data can still be a valuable resource in guiding future experimental and theoretical work. This will be the first time that François engages with philosophers of science, which is both an exciting and intimidating prospect for me!

I will also be mentored by Pr. Sébastien Le Picard, who is a professor specialized in molecular physics, responsible of the astrophysics axis, at the IPR. Sébastien has developed an expertise in uncertainty management techniques as they apply to building photochemical models of Titan’s atmosphere, and will therefore help me to navigate the use of sensitivity analysis in astrochemistry and its application to Titan’s atmosphere. The successful outcome of this Marie Curie project greatly results from his efforts, during the last decade, to promote philosophy of science and establish connections that were wanting between philosophers and physicists in Rennes 1.

What lead you to pursue this field of study & this research project? Were there specific people, courses you took, or other experiences that first sparked your interest in astrochemistry?

During my PhD at the University of Western Ontario, I worked under the supervision of Pr. Chris Smeenk, and  gradually specialized, due to his contagious enthusiasm, in the philosophy of cosmology and astrophysics, with a focus on interdisciplinary facilitation and on the methods for eliminating model and observation uncertainties (be it numerical artifacts in astrophysical simulations or random and systematic errors in astronomical measurements). My research has convinced me that astrochemistry holds key information for tackling some of the most important cosmological questions. The chemical evolution of the interstellar medium, for instance, is a determining factor for how structures such as galaxies, stars, and planets form in our universe. Yet, very often, astrochemistry is reduced within hydrodynamical simulations to a set of purely numerical, physics-free, parameters tuned to reproduce observations. Likewise, cosmologists such as T. Abel have insisted on the hidden resources that can be found in astrochemistry— e.g., how the spectroscopic analysis of  molecules could constrain solutions to the Hubble constant crisis.  I met Sébastien as he had invited me to give a conference at the IPR back in 2019, in the continuity of his efforts to create a dialogue between philosophers and physicists. We have been working together for almost one year to build this unprecedented project in France, with a philosopher hosted, trained in a physics department and participating to the life of the laboratory, while training students to philosophy of science and helping to facilitate interdisciplinary work in return.

You graduated from Western in 2019. Could you tell us a bit about your experience as a graduate student and a member of the Rotman Institute? What have you been up to since graduating? 

I became a resident member of the Rotman Institute of Philosophy after one year at Western Ontario. I found in the Institute exactly what I was looking for when I decided to leave France back in 2015, after my Master at the Université of Paris 1-Panthéon Sorbonne. The Institute provides a stimulating environment where graduate students don’t work in isolation, where lasting collaborations regularly emerge from informal discussions around the espresso machine, where graduate students have the opportunity to present their work to scientists who are willing to listen to philosophers and to give them feedback. This environment has been decisive in forging my philosophical interests, my vision of my work, my understanding of the most pressing challenges that scientists face today and of the role of philosophy of science in face of these challenges. I am really grateful for having been part of this exciting adventure.  After graduating, I spent 8 months at the Center for the Philosophy of Science at the University of Pittsburgh as a postdoctoral fellow. The Center is devoted to promoting teamwork, collaborations, exchange with fellows from all over the world and with scientists from all areas – a perfect place for me. Since September 2020, I have been a research associate for the Rotman Institute, working with the New Directions in the Philosophy of Cosmology group.

When you aren’t working on philosophy, what other things do you enjoy doing?

I started my professional career as a pianist and a music teacher, and music has kept a central place in my life- especially baroque music and opera. I am always surprised at how a good musical choice can change a day of writing!

But after a long day spent sitting in front on my computer, I find nothing more relaxing and energizing than an intense kickboxing or MMA workout.

Pictured above: Marie Gueguen in Pittsburgh.