Chemistry, as a science, lies somewhere between physics and biology. In many ways all these sciences are interrelated, but they do have essential limitations that hinder their reduction to one another.
Chemistry deals with atoms and molecules, and inter-atomic and inter-molecular structures, and how they interact chemically; while physics and biology deal with visible matter and try to discover the micro structure only coming down from their macro lenses.
But this seeming difference is also superfluous, as the real problem of chemistry is that although it boasts as being a science of the atomic and subatomic levels, it too has been a top-down technique, relying on theories about the atomic realm basing on sensual properties of the substances under study. As far as the atoms and molecules are concerned, no one has actually seen them, even with latest techniques like the scanning tunneling microscope (STM), which is a type of microscope used for imaging surfaces at the atomic level. This technique can distinguish features smaller than 0.1 nanometer, but the image retrieved is based on the readings of the passing current and is not any direct image — so, no one has ever seen the actual atoms yet.
The hundreds of millions of substances that chemists study, their structures, their chemical properties and their interactions are really not determined by a bottom-up methodology wherein the knowledge of the parts would determine the knowledge of the whole. Rather it is a reverse-engineering based on hundreds of years of hit and trial experimentations that have brought into observation definite patterns of behaviours of substances, and the same lead to the theoretic construction of the basic structure of the substances and their bonding at the atomic level.
For this reason, there have been two overarching groups in the philosophy of chemistry: Substance Philosophers, who prioritise basic entities over changing states and processes; and Process Philosophers, who confer to the fact that there are no fixed and isolated chemical substances in the natural world but only permanent chemical change of matter. It is clear that such a dichotomy arises because there is no means of ascertaining the physical reality of the atoms, their structures, or their bonding etc.
When physics, on the other hand, tries to ascertain the same, it enters the quantum realm, which again, is mostly a mathematical and theoretical realm, but which talks of the subatomic particles — not atoms or molecules. In fact, quantum physics has blurred away the orbitals in the atoms, upon which all chemical structures are based. This is the reason why it is hard for the two sciences to reconcile — because quantum physics is on its way to reducing matter to massless waves that only occasionally ‘appear’ to hold mass, whereas chemistry creates its extensive molecular world to explain the sensical changes in the material world around us.
And this assumptive chemical world certainly rests upon unfirm, wobbly foundations. For instance, if we take the example of water, its structure continuously changes on a time scale of less than a trillionth second and hundreds of kinds of structures recur on time average, so much so that in liquid water one can single out hundreds or thousands of different kinds of molecules, making even ‘pure water’ a complex molecular mixture. Yet, this all is in the lab, because before it was sampled out, it was part of an even enormous continuous nonhomogeneous flux of matter and interactions. In the lab, the first step of any procedure is to purify the substance as much as possible into a single homogeneous substance, thus bringing it into a fake, lifeless environment. So, how do chemists deal with the real world — by making assumption about what is relevant to their specific questions, and by trying to control other related factors, and achieving required estimates. And once the estimates have been found, there is no further attempt for any abstract ideal of complete and perfect knowledge.
Rather, in practice, chemistry is guided by a pluralism of methods — each subdiscipline has developed its own methods, concepts and models that suit the substance classes under study. This methodological pluralism allows flexibly dealing with complexity by splitting up approaches according to what matters in each case. So, rather than going for universality, chemistry goes for pragmatism and usefulness, and its theories work in the reasonability of the specific kind of system and research in each subdiscipline.
The fact that in chemistry, substances have their empirical basis in the Periodic Table and on the existence of (simple) substances that cannot be separated into other substances by chemical means, deems the fact that structure is imposed upon basic substances according to lab-findings. Lavoisier famously acknowledged that “the concept of basic substance as such does not in itself contain any idea of atomism”, rather they are the unobservable, ultimate constituents of matter. According to Klaus Ruthenberg, “basic substances are non-observables and rather concepts than concrete objects. They are not bearers of properties”, meaning that chemistry deals with homogeneously behaving ‘substances’ and that the theories about their deeper structures are a just means to understand them better. H Hettema wrote, “explanation of chemistry by physical theory has many complications, and the physical foundations of chemistry are found in a multitude of physical theories, patched together with assumptions, approximations and special applications.”
Experimental results in chemistry show that when temporal and modal parameters are changed, the ‘substance’ does not always behave as a collection of molecules or atoms, and they may exhibit different mereological partitionings, which would lead to different conceptions of the ‘atom in a molecule’. Furthermore, parts and wholes come out differently depending on the levels of calculation or the apparatus being used.
This contrasts with the universal ‘Theory of Everything’, the ideal that theoretical physics pursues. Wherein it is idealised that when the deepest structure of matter will be revealed, all sciences will be explained by a single model — an ideal that seems principally impossible. The reason being that much of the structures talked about in physics and even in biology are equally ‘patched together with assumptions, approximations and special applications’, so that the bulk of these sciences are ‘theories’ that give best explanations, not undeterrable ‘facts’.
In fact, Quantum Mechanics simply cannot lead to Chemistry’s classificatory concepts of substances and reactions, nor can it explain, or ever reach chemical structure theory from bottom up. So, till now, nature seems to be constructed upon a reality that has several true, working levels and layers that work flawlessly in their respective realms; and even if nature will, one day, reveal where these realms meet each other, the awe that they still are true and working, seemingly independent systems, will remain.
Published in The Express Tribune, December 31st, 2021.
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