Who are we?

Sarah Hijmans

I am a PhD student in history and philosophy of chemistry at the Laboratoire Sphère (Université Paris-Diderot) in Paris, France. My research is mainly focused on the concept of chemical element and its historical development, but I am also interested in chemical classifications and laboratory practice.

The main aim of my PhD is to find out how chemists identified chemical elements during the eighteenth- and nineteenth century. In theory, they agreed that a substance was elementary when it could not be decomposed in the lab - but it was not always possible to apply this criterion in practice. It seems that for a new element to be accepted, its similarities to known elements might have been just as important as its indecomposability.

Vanessa Seifert

I am interested in examining standard issues of the philosophy of science, from the novel and relatively unexplored perspective of chemistry. This includes questions such as: how does chemistry contribute to our understanding of the world around us?; what is the relation between chemistry and other sciences like physics and biology; and, do chemical entities and properties like molecules and chemical bonds, exist?


I currently work as a post-doctoral research associate with the ERC project 'Metaphysical Unity of Science' (grant no. 771509) at the University of Bristol. In the context of the project, I explore chemistry's role in our metaphysical understanding of the world, and examine alternative positions on the unity of the sciences, with a particular focus on chemistry and its history.


My undergraduate studies were in Chemical Engineering from the National Technical University of Athens. I then pursued an MSc in Philosophy of Science from the London School of Economics. I recently completed my PhD in Philosophy under the supervision of James Ladyman at the University of Bristol. 

For more info on what I do, check out my personal website!


Karoliina Pulkkinen

I'm a philosopher of science with a special interest in how values influence chemistry and climate modeling.

I’m currently working as a postdoctoral researcher in KTH Royal Institute of Technology. Prior to moving to Stockholm, I was a Ph.D. candidate at the Department of History and Philosophy of Science at University of Cambridge. In my doctoral research, I investigated the role of values in developing the periodic systems of chemical elements.

In my PhD monograph, I argued that examining the competing periodic systems with the framework of values gives us an especially insightful explanation of their differences. My thesis demonstrates how three chemists – Mendeleev, Julius Lothar Meyer, and John Newlands – emphasised different values when developing their systems in 1863-1875. While no chemist emphasised just one value, I argue that Newlands elevated simplicity (“simple relation”), Mendeleev completeness (polnost’), and Meyer carefulness when systematising the elements. I also identified a relationship between values guiding the development of the systems and chemists’ subsequent uses of their systems.