Philosophy of chemistry – that is a thing! Whether one thinks of it as a separate field of philosophy or as a sub-discipline within the more general philosophy of science (who cares anyway!), there is no doubt that chemistry provokes interesting philosophical questions. The aim of this article is to sketch the main philosophical issues that are investigated from the perspective of chemistry and in this way explain what people mean when they say that they are doing research on the philosophy of chemistry.
So, chemistry and philosophy; how do these two relate? What does philosophy have to say about chemistry that might be interesting to chemists, and what is chemistry offering to any kind of philosophical discussion? After all, physics seems to be the mother of all empirical sciences and if one wants to investigate philosophical questions in terms of empirically validated and rigorously justified propositions, one would most probably search for answers in physics. And indeed, there is a separate field that deals with the epistemological and ontological issues that arise through the study of physics, namely the philosophy of physics. Given all this, what kind of philosophical issues does chemistry introduce that are not already addressed in the context of physics? What is it about chemistry that not only raises interesting philosophical questions, but also renders such an investigation a separate, autonomous field?
In a nutshell, philosophy of chemistry signifies the systematic expression and development of philosophical interest in chemistry. It involves a critical analysis of the concepts, theories, methods and representations employed in chemistry and by chemists, as well as the investigation of the inter-relations developed between chemistry and other sciences (such physics, biology and chemical engineering).
While philosophising about chemistry was prevalent since ancient times, the philosophy of chemistry as an organised research study is a relatively new field that flourished in the past 20 years. One of the key events that signified the formation of this field was the foundation of the International Society for the Philosophy of Chemistry (ISPC) which organises annual conferences since 1997 and publishes its journal Foundations of Chemistry since 1999. This is accompanied by the publication of books and collections of papers as well as by the publication of articles in philosophy of science journals such as Philosophy of Science (PSA) and the British Journal for the Philosophy of Science (BJPS). Moreover, the presence of the philosophy of chemistry has expanded online. Notable examples are the electronic journal HYLE: International Journal for Philosophy of Chemistry, and the entries on philosophy of chemistry in the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy.
Here are some of the issues that philosophers of chemistry are interested in.
First, there is the conceptual analysis and clarification of chemical concepts. This includes investigating atomic and molecular structure, as well as the chemical concepts involved in their description. It involves the investigation of the representations of the structure of matter, the atomic model, the numerous concepts that describe matter (such as substance, mixture, compound, molecule, element), the description of chemical reactions and the periodic table.
Secondly, there are questions about mereology. Various classifications of matter into substances, elements, compounds, etc. are examined, as well as the role of the periodic table as a method of classification and prediction of the chemical characteristics of elements. Historical investigations of chemistry contribute largely to the discussion of mereological issues, since various chemical concepts have acquired different meanings since antiquity.
Realism is also a heated topic within the philosophy of chemistry. In this context, one investigates different realist and anti-realist stances with respect to specific chemical concepts. There are various positions that one could take with respect to chemical concepts and theories, such as supporting entity realism with respect to atoms or molecules, structural realism with respect to chemical bonds, or an antirealist stance about chemistry. How chemistry is related to other sciences is also a crucial question which is often investigated in connection with questions about realism. This involves the possibility of reducing or unifying chemistry to physics, and examining what kind of relation could correctly characterise such a unification. The issue of a broader unification is also investigated, as well as the possibility of understanding chemical ontology and practice in terms of some form of emergence or pluralism.
Moreover, what sort of explanations do chemical hypotheses provide with respect to the phenomena examined by chemistry? This question often involves comparing chemical explanations with explanations provided by physical theories that attempt to provide their own account of chemical phenomena. Furthermore there are questions concerning laws and models in chemistry. These questions include whether there are laws in chemistry, what the status of chemical law is, and how important the role of the empirical versus the mathematical expression of those hypotheses is. Models in chemistry are also closely connected to discussions about laws in chemistry. This includes investigating the role of idealisations and approximations in the formulation of chemical hypotheses, as well as the status of chemistry as a special science.
Furthermore, chemistry is unique compared to the other empirical sciences in the sense that experimentation plays a particularly important role not only in testing chemical hypotheses but also in formulating them. This prompts various interesting issues about the role of experimentation in chemical investigations but also the possibility of making generalised hypotheses for the explanation and prediction of chemical phenomena. In this context, one also investigates the methods employed by chemists. Relevant questions include the importance of induction (through the particularly vital role of experimentation in chemical theorising), as well as the role and level of abstractness when formulating chemical hypotheses.
The history of chemistry plays an important role in the analysis of all these philosophical questions about chemistry. For example, the changing perceptions of chemical concepts- such as the image of the atom or the classification and understanding of substances from Aristotle and onwards- play a crucial role in the philosophical analysis of chemistry. Another example is the Chemical Revolution which is examined both with respect to the changing theories in chemistry but also with respect to the work of main contributors in chemistry.
Lastly, it is no surprise that chemistry’s role in environmental, healthcare, and societal issues prompts the investigation of ethical questions. What is the moral responsibility of chemists given the current environmental and healthcare challenges faced in the world; what constitutes ethically responsible research and how should knowledge production be influenced by such ethical questions? There are just a few of the moral issues that are raised with respect to chemical practice.
All in all, chemistry has a unique history and role in society, and employs its own concepts, methods, tools, explanations and laws when investigating chemical phenomena. This prompts fruitful and interesting philosophical questions. The philosophy of chemistry encompasses this philosophical work by systematically examining philosophical questions from the perspective of chemistry.
* Vanessa is a postdoctoral researcher in the University of Bristol, working for the European Research Council Project ‘The Metaphysical Unity of Science’ (grant no. 771509).