four classical elements of Empedocles/Aristotle are still in the reduction- ist position with the adjective âfewâ. Thirty-three is too many; the ques- tion of numbers ...
Conclusions
At the end of this book, we shall try to summarize some of the points we have dealt with. In particular, we have focused on four essential points, which have become progressively more general: 1. Chemistry as a science of the multiplicity and qualitative differences. 2. The structure of matter and the irreducibility of the latter to other physical concepts, whether mass or energy. 3. A structured matter at the microscopic level (atoms and molecules) and a qualitatively differentiated at a macroscopic level (elements and compounds) as a source of explanation of the properties and changes of the world. 4. and, finally, chemical approach as a prototype of a general explanation and applicable to both natural sciences and human ones. The reality of the inanimate and animate world around us is qualitatively differentiated, vastly differentiated. Four positions are possible to analyze and study this multiplicity, and, historically, all have been used. We shall summarize them with the following adjectives: one, few, many, infinite and they are related to the number of elementary substances used to explain the multiplicity of reality. The first position, the one connected to the adjective “one”, has been called “reductionist”, although the term is recent and the position ancient. It can be exemplified by the Greek atomistic view, but is not specific of the microscopic world. This view, in fact, could very well be exemplified also by the monistic positions of pre-Socratic or by the “theory of everything” to which physics aspires today. Considering the classic atomistic vision, do no exist qualities at a microscopic level that can differentiate the atoms and, therefore, one single substance exists, differentiated in the atoms by the amount (shape, size, movement), and these generate the qualities perceived in the macroscopic world. Aristotle can exemplify the second position, which is connected to the adjective “few”. For him, there are four elements, a small number that al127
Giovanni Villani
lows us to remain in a reductionist perspective. By continuously mixing these few items you can get infinite qualities. The third position, connected to the adjective “many”, is the chemical perspective. It seems to us that this position was never attempted in the classical period and therefore its “emergence” is a novelty that Chemistry gives to cultural heritage and general philosophical. It tells us that the qualitative differences in the macroscopic world are not all elementary. All substances can in fact reduce to a certain number of elementary substances, not small to render the reductionist position impractical. When Lavoisier, with his definition of element, gets 33, there was an epistemological leap that has been emphasized in this book. The three principles of Paracelsus, the three earths of Becher, the five elements of Lemery or the four classical elements of Empedocles/Aristotle are still in the reductionist position with the adjective “few”. Thirty-three is too many; the question of numbers becomes an epistemological divide. Today Chemistry uses 92 elements, but Chemistry goes further. It also uses about ten million synthesized compounds, and the many other potentials, each one with a name, all subjects of chemical action and objects of study that form the basis for the explanation of the complexity of reality. However, the adjective is “many” and not “infinite” to emphasize two aspects. For one thing, not all virtual combinations are possible in nature. In Chemistry, as in language, there are “affinities” that make certain combinations possible and preclude others. Even those who know little English know that the word “aaafffggetvd” does not exist in that language because a vowel or a consonant repeated three times is not found in any word of that language. This important aspect has been poorly highlighted in the epistemological context and poorly claimed by chemists, but is useful not only in natural sciences, but also in human ones. Then, there is a second aspect to be highlighted on the “many”, but not “infinite”, pure chemical substances: not everything that seems simple at the macroscopic level (for example, wood, wine, etc.) is really simple and has a microscopic entity as counterpart. Indeed, we can say that despite the millions of pure substances identified by Chemistry today, the majority of substances do not fall in this concept. There are, in fact, very few chemical compounds in everyday use. The most important one is surely water, but it is definitely not easy to find pure water, followed distantly by table salt, some inorganic compounds (ammonia, soda, etc.), some organic products and medicines. At this point, it should be clear that the concept of elementary substance should be removed and replaced with that of pure substance, a systemic synthesis of a new entity, whose properties are different from those of the constituents. 128
Conclusions
The fourth position, that of the adjective “infinite”, argues that there are endless different pure substances and all macroscopic differences are to be moved into the microscopic world. From the classical point of view, it was the view of Anaxagoras and of the Aristotelian medieval concept of minima naturalia. The second point we want to highlight in this Conclusion can be related to the question: Is matter really reducible to energy? If the matter is that of physics, the mass, then this reduction is not only possible, but also conceptually accomplished, as Einstein taught us. The mere fact that nature behaves as if there were two separate conservations laws, since the transition between mass and energy is not found at the macroscopic phenomena level enables us to keep these two concepts separate. In fact, this book argues that there is a plurality of meanings of the concept of matter. The concept of matter used by chemists provides a plural reality explained at the microscopic level with a structured matter, be it the atom or the molecule. This structured matter is not attributable to energy except, at the cost, of deconstructing it. We believe that statements like (Selleri 1987, p. 166) 1: “The difference between an object and its field is not so important, if both can be seen as ways of being of energy. The difference is quantitative”, typical of physicists, are fundamentally wrong because an object is not only its mass and it is this, and this alone, which can be transformed in energy. The third point, closely connected to previous one, which we want to highlight in this Conclusion, is the relation between the macroscopic variety and the microscopic structure of the matter. Why are there 92 elements? The atoms of each chemical element are qualitatively different from each other because in the assembly of their constituents has been create a structure. Although these constituents are “few” (proton, neutron and electron) they can form “many” different atoms, not only because several can put together (quantitative reason), but mainly because these subatomic particles come together to form a new global unity, creating an atomic structure. For the same reason the 92 different atoms form millions of different molecules not only with their different amount (composition), but for the molecular structure that, they generate when they group. We mentioned that the concept of structure could relate the chemical approach to the Sciences of Complexity and to Systemics, in terms of “emergent properties” of the global system (in this case the molecular structure). 1 In the original: “La differenza fra un oggetto ed il suo campo non è poi così fondamentale, se entrambi possono essere visti come modi di essere dell’energia. La differenza è quantitativa.”
129
Giovanni Villani
This solves the problem, already highlighted by Aristotle and present as a critical point in Democritean atomism throughout the period of its use, of the “newness” of the mixed compounds. The fourth, and final point, to highlight in this Conclusion is that the concept of the system, as a structured entity, allows an explanation of reality made through entity and not only through laws. The behaviour of matter and its variations, in fact, are explained in terms of presence and of properties of constituents and in terms of properties that emerge in their association. These two types of explanations create two different approaches, physical and chemical, to the scientific study of matter. An important point to emphasize is that the chemical explanation, in terms of “constituents”, is not in contradiction with considering a structured reality as “unique”. Explaining the molecular properties in terms of atoms or macroscopic properties in terms of atoms or molecules, means trying to give “understanding” to events and individual bodies for “comparison” with other facts and entities equally individual. This scientific method has nothing special, as it is one of the modes of human understanding. The physical explanation and the chemical one, the first in terms of laws and the second for presence and properties of systems, are two general ways of explanation. A single unique fact must always be connected to others to be understood. The connection always occurs by the inclusion of individuals in “groups” whether they created by law (all the as are bs) or by highlighting the common properties, as Chemistry does. Grouping individuals into classes does not negate the individuality of the individual, but allows you to “understand” the properties that several individual entities have in common. These different approaches (physical and chemical) are the same ones used in the study of human actions. Even in this case, each action is unique and is accomplished by a single subject. However, if we were to stop at this you could not “explain” any human behaviour, neither single nor collective. Why has someone decided to do such a thing and not another one? Why did that fact happen? It is difficult to apply the physical approach to human and social facts; by grouping the individuals into structured entities (classes, peoples, nations, etc.), it is possible to use the properties of these ensembles and their interrelations, in other words through an explanation of chemical type, we can explain human and social actions. As a result, Chemistry, which has always used such an explanation “for entities”, may represent a prototype of explanation for humanities and social sciences, much more than Physics. In addition, it must be kept in mind that an explanation of a physical type favours the dynamic aspects (events) ignoring almost completely the subjects to which they apply these events; the chemical explanation, in130
Conclusions
stead, equals the static and dynamic aspects, entities and their events of transformation. The static aspect of the structure, the detection of the presence of such an entity, enables a part of the explanation of an event, but only a part. The dynamic aspect, both in terms of a reversible or cyclic time and in that of an irreversible one, completes the explanation. We have seen that in fact, absolute “entities” do not exist and only a suitable timescale allows you to overlook certain processes, creating static entities, but this philosophical “truth” does not affect the chemical explanation. A biological example is opportune. After the theory of evolution of living species, no one wanted to cancel the concept of species because it is not fixed forever. When we are interested to times in which the species (both chemical and biological) can be considered fixed, the utility of the concept of species is obvious. This concept, however, is enhanced by the possibility of explaining the birth and death of these species (both chemical and biological), i.e. for the transformation of such systems in evolutionary biology as well as in chemical reaction. The request to highlight the specificity of Chemistry present throughout this book is not based, therefore, on an absurd and anachronistic “defence of the shop owners,” but on a real and essential epistemological point: Chemistry and Physics are the scientific counterparts of two general and different ways of approaching material reality. We have said, and repeated many times, that the physical and chemical approach may be useful as a prototype for the human sciences. We also argued that the chemical approach seems to us more suitable for the purpose and this is another important reason why we have insisted so much on the specificity of Chemistry. The reason of the suitability of Chemistry in this type of explanation is due to the use for a long time of a systemic complexity approach in this discipline, as we have shown, and the need of this type of approach also for social and human disciplines.
131
