Scientific realism, the idea that science reveals truths about the nature of reality, has long been a central theme in the Philosophy of Science, influencing our understanding of knowledge and reality. But how does this issue manifest itself in the Philosophy of Chemistry? Unlike other sciences, Chemistry relies on multiple, often overlapping, models to represent reality.

This multiplicity of models raises particular questions about how chemists perceive and represent reality. Exploring this perspective, researchers investigated the unique spatial dimension within Chemical Realism, drawing inspiration from the work of French philosopher Gaston Bachelard. The aim was to analyze how chemists construct and interpret models, intuiting the space of atoms, molecules, and chemical processes as a whole. Using the Daniell cell — a classic electrochemical system — as a case study, the work reveals how these spatial intuitions shape chemical epistemology and may impact science education, especially in the training of future teachers.

“I believe this work can contribute mainly to teacher training, offering support for this. We were able to identify realism in specific concepts, especially through spatial realism. It is often said that chemistry is realistic, but how exactly? Our approach analyzes the representation of space in a semiotic way, allowing us to identify this realism, as we did with the Daniell cell, for example. The same can be done with many other models,” explains Artur Aldi, a master’s student in the Interunit Postgraduate Program in Science Teaching at Universidade de São Paulo (USP), under the supervision of Professor Carmen Fernandez, from the Instituto de Química at USP and a member of the RIDC Redoxoma. The article by Aldi and Fernandez was published in the Revista da Sociedade Brasileira de Ensino de Química (Journal of the Brazilian Society for Chemistry Education).

According to Aldi, “The idea is to shed light on something that seems obvious but is not: the complexity of the levels of representation in Chemistry. Realism is present in textbooks, but do teachers know how to recognize it and work with it? Do they understand the different levels of representation superimposed on these materials?”, asks the researcher.

Better teacher training will directly impact the quality of teaching. For Fernandez, “The idea of ​​chemical realism is embedded in textbooks, which makes teaching easier, but it also creates obstacles. The model comes to life there in the book, in the drawing, but it is not reality, it is just a model. I think this is the biggest difficulty for students: they enter this world as if it were a video game, where everything works in a specific way but is, in theory, meant to explain reality. This transition between model and reality is complex, especially in Chemistry.“

In textbooks, it is still common to find images that reinforce this confusion. “For example, a beaker with a microscope showing molecules, as if the chemist could see them directly. This makes understanding difficult, because in the same drawing, we have both macroscopic and submicroscopic representations, without a clear distinction,” explains the researcher.

Scientific Realism in Chemistry

Scientific realism argues that science accesses reality and builds knowledge about it to understand it. It is a broad philosophy, as it defines not only the purpose of science but also how we should understand scientific knowledge and what characterizes this knowledge.

When the Philosophy of Chemistry investigates how this science conceives reality, it reveals specific features not found in other scientific domains. These particularities call for adaptations to the traditional theses of scientific realism. “A very peculiar aspect in chemistry, for example, is the plurality of models. To describe the same entity – the molecule –, we use different representations, such as structural formulas, line formulas, molecular formulas, and models based on orbitals. Analyzing these different representations, we can find some that are contradictory to each other. The question then becomes, what is the meaning of Truth when we can understand reality in so many different ways?” explains Aldi.

Classical scientific realism is strongly associated with the idea that true knowledge describes reality. However, when we consider Chemistry and its diversity of models, this notion becomes more complex. “And that is what I try to do in my work: to describe how chemists understand how to access and work with reality. That is the goal, in essence,” concludes the researcher.

Bachelard and the Concept of Space

In his book The Experience of Space in Contemporary Physics, Gaston Bachelard seeks to establish how science and scientists understand the concept of space. He recognizes that science does not maintain a single philosophical approach over time. On the contrary, its ways of constructing knowledge evolve, going through different phases. Bachelard identifies two distinct ways of interpreting space: a realistic and a rationalist view, this one aligned with the advances in quantum mechanics.

The realistic notion of space proposed by Bachelard, according to the researchers, closely aligns with how chemists formulate their concepts. It is founded on the principle that objects exist to the extent that they can be precisely situated in space.

“This principle is the basis of chemical structure. For example, when we perform an X-ray diffraction (XRD) analysis of a molecule, we obtain well-defined spatial coordinates. These points delimit the position of the atoms, and through these precise locations, we confirm the existence of the molecular structure. Thus, the construction of chemical concepts follows this same logic: if we know the location, we know that the object exists. Furthermore, it is the difference in the occupation of space that distinguishes one molecule from another. This is, of course, thinking about modern chemistry,” explains Aldi.

This perspective highlights the importance of analyzing chemical concepts in detail. “We cannot treat Chemistry in general terms, just as we cannot simply talk about Physics in general. It is essential to address specific content, such as electrochemistry and thermochemistry, to better understand the particularities of each area,” says the researcher.

When analyzing chemical realism from Bachelard’s perspective, the researchers emphasize the importance of making explicit the different representations used in Chemistry, helping teachers and students understand that scientific models are not reality itself, but tools for interpreting it.

“I believe it is essential for students to learn this idea of ​​a model, not only for Chemistry, but for other sciences as well. They need to learn that science works this way, that these models are being tested all the time, and sometimes they fail, and a new one needs to be created. And that is why I can trust science,” concludes Fernandez.

The article Scientific Realism in Chemistry and the chemical Intuition of Space: philosophical considerations and applications in Teaching, by Artur Aldi and Carmen Fernandez, can be accessed here.