Amanda Nichols (Oklahoma Christian University), Myron Penner (Trinity Western University)
In the late 19th century, Sophus Jørgensen proposed structures for cobalt complexes that utilized the more developed bonding principles of organic chemistry and the reigning understanding of valence. Similar to how organic compounds typically form hydrocarbon chains, Jørgensen created models for cobalt complexes that also had a chainlike structure. His models featured (1) a cobalt metal center with three attachments because cobalt was understood as trivalent and (2) one of those attachments was a chain of atoms, like the carbon chain featured in organic chemistry.
Alfred Werner proposed a different model for cobalt compounds that featured octahedral arrangements around the cobalt metal center, calling the metal complex a coordination compound. Werner’s coordination theory introduced a new type of valence allowing cobalt to have six attachments and abandoned Jørgensen’s chain theory. Experimental work confirmed Werner’s theory making it central to inorganic chemistry.
One issue in the Jørgensen-Werner debate over the structure of cobalt complexes concerns differences between the two scientists over the nature of theoretical justification-- the epistemic reasons each had for resisting change (as with Jørgensen) or looking for a different model (as with Werner). In our paper, we compare and contrast the concepts of theoretical justification employed by Jørgensen and Werner. Jørgensen felt that Werner lacked justification for his experimental model. Werner, presumably, had some justification for his model, albeit a different sort of justification than Jørgensen.
While Werner constructed a radically different and creative model, Jørgensen resisted revision to the established framework. Werner emphasized symmetry and geometric simplicity in his model, and the consistent patterns that emerged were viewed as truth-conducive. Jørgensen, on the other hand, criticized Werner’s model on the basis that it lacked evidence and was an “ad hoc” explanation. Jørgensen disagreed that Werner’s method of hypothetical reasoning was the best approach in theory-building. G. N. Lewis’ electronic theory of valency and later theories, such as crystal field and molecular orbital theories of bonding that explain Werner’s coordination theory were not developed until later. Though Werner seemed comfortable proceeding with details not settled, Jørgensen was not. Werner’s descriptions of his model would frame him as a scientific realist, while some historical evidence suggests that Jørgensen could be classified as an anti-realist. Assuming this, we explore the contribution realism makes towards the progress of science, and how anti-realism might hinder. We conclude by noting how the different concepts of theoretical justification embodied by Jørgensen and Werner help us understand both continuity and diversity in multiple approaches to scientific method.
