What has Philosophy to offer to Chemistry?
Nikos Psarros, Leipzig
Index
Philosophy’s offer to Chemistry
Philosophy, a partner of Chemistry
Browsing a catalogue of publications in philosophy of science one will notice that while there exist some tens of thousands of contributions to philosophical problems of physics and in later times also to philosophical problems of biology, cognition science or psychology, the number of the corresponding works devoted to chemistry makes up only a small fraction of them. What are the reasons for this “neglect of the philosophy of chemistry” that is still affecting the discourses in the philosophy of science until our days in spite of an outburst of activities in the last four years?
One reason may be the fact that the majority of chemists adore more or less some form of scientific realism that ascribes the objects of chemical theories, i.e. molecules, atoms, structures etc., the status of “constituent parts of the world”. In introductions to chemical textbooks, especially to older ones, there is often the claim repeated that chemistry is one of – or rather the – oldest human enterprise because all changes in the material world involve in one way or an other chemical processes, making superfluous a philosophical treatment of the “obvious”. On the other hand, although two of the most influential modern philosophers of science, Emile Meyerson and Gaston Bachelard, have been trained chemists, it seems that in philosophical circles the view predominates that chemistry does not provide the ground for the flourishment of typically philosophical questions. This is perhaps so because in contrast to physics and biology that – with the development of relativity theory, quantum mechanics, evolutionary theory, and genetics – trespassed the margins of human imagination and shook the traditional views about the cosmos and man’s place in it, chemistry, during the historical period of its maturing as a science, was not involved in answering any cosmological, theological or existential questions but was rather busy providing materials and methods for laying down the fundaments of the wealth of some nations, improving the standard of living of their populations and setting the seeds for the various environmental and social problems their descendants are toiled with.
There is also the claim, that since chemical theories could or should be reduced to physical ones, all philosophical questions connected with them can be reformulated as questions of the philosophy of physics. An additional argument against the existence of an autonomous philosophical concern with chemistry is that this science lacks the dramatic turning points or “crises” that have marked the development of physics in the late 19th and early 20th century.
Apart from the general remark, that the conclusion that chemistry is not susceptible to philosophical analysis is itself a philosophical statement, the successful rebuttal of the other arguments against an autonomous philosophy of chemistry depends to a great extent on the appropriate definition of the aims and the methods of philosophy itself. In its beginnings in the Greek Ionian antiquity, philosophy was trying to give an explanation for the coming into existence of the world, without recurring to theological or superstitious ideas. Later with the Athenian sophists, their opponent Plato and his successor Aristotle, philosophical efforts focused on the distinction of “truth” from the “apparently true”, a problem that was approached by various methods. However, the philosophical discourses of the antiquity and the following fourteen centuries remained confined into the boundaries of ontology, i.e. the discussion about what is the object of knowledge.
Descartes marks the first “turn” in philosophy towards the subject of knowledge, the human intellect, and he also establishes its function as a “metascience”, a science about science, by raising questions like “what can we know?” and “how it is possible that a true knowledge is true for every intellect?” He is the starting point of the diverging ways that led to modern idealism, transcendental philosophy, empiricism, positivism, pragmatism and phenomenology, philosophical positions that predominated the discourse in the three succeeding centuries. At the end of the last and the beginnings of our century the second major turn in philosophy occurred when first Frege and later – more thoroughly – Wittgenstein showed that the solution of many philosophical questions depends on the meaning of the words and on their use. Since this “linguistic turn” we can restate more precisely the somehow vague definition of philosophy as «the rational, methodical, and systematic consideration of those topics that are of greatest concern to man» by adding that this consideration is focused on the languages that man uses in order to communicate and orientate himself in those various topics.
This brief and rough sketch of the development of philosophy should not insinuate that there is a linear advancement in “philosophical knowledge” in the same sense as we think that there is a progress in our particular technical or scientific capabilities. Although also modern philosophers “know” more than their predecessors, the very nature of philosophy as a discursive metascience hinders the philosophical work of past philosophers from becoming obsolete. While a two hundred year old science textbook is only of historical or philosophical interest and his utility for modern empirical science is very limited, a modern philosopher is always in position to review critically the work of a long deceased colleague, to reinterpret it, to gain some new insight from it, to comment on it, and finally to arrive to a synthesis of new and old ideas. Thus philosophy has a moment of “time travel” although the corresponding journeys have a surprisingly low-tech demand on equipment.
This presentation of the aims of modern philosophy is, however, still insufficient for the elucidation of the question that was raised in the title of this essay. For, the knowledge that knowledge itself depends on language, and that science formulates statements using a special vocabulary does not determine which kind of statements are the “scientific” ones and which vocabulary is appropriate for a given science. Moreover, depending on the function that is ascribed to language, there are many possible ways to conduct philosophy of language and hence linguistic philosophy of science. Thus within the tradition of the nowadays predominant “analytical philosophy of science” emerged at least two approaches that will be called here – for the sake of argument – the ‘naturalist’ and the ‘culturalist’ approach. Again this distinction does not mean that we are dealing with two homogeneous, mutually feuding “schools” of philosophical thought, but rather with two wide and partially intersecting groups of various positions that share some common traits.
Naturalism
The central issue of the ‘naturalistic’ positions is that the sole authority for the supply and the legitimisation of scientific terms and scientific knowledge are the sciences themselves with their empirical methods. Further, since most sciences define themselves as enterprises for the exploration – by means of observation – and the description of a particular region of the “nature” that surrounds us, their languages have been also ascribed a descriptivist function. In the various naturalistic idioms scientific statements describe facts of the “natural” world that are thought to be accessible independently from the cultural circumstances of the observers, the scientific character of a statement being established by means of its empirical confirmation. An other common trait of naturalistic positions is their rejection of knowledge or of statements that are valid a priori. This means that also the methodological rules that govern empirical validations, i.e. rules for performing experiments, conservation “laws”, logical axioms etc., are supposed to be justified empirically, even if this is not evident prima facie.
The role of philosophy is on a naturalistic playground somehow limited: It can describe the structures of scientific theories, analyse them for logical consistency, elucidate semantic and pragmatic aspects of scientific terms, but it cannot give – since there is no place for it – any normative aid in cases of terminological ambivalence or in cases where it is desirable to know in advance if a proposed statement is worth to be put under experimental scrutiny or not. Apart from these handicaps, the naturalistic approach encounters some additional problems with far reaching implications: It has to accept for instance a historically contingent scientific practice as the normative frame that provides the criteria for the evaluation of the scientific status of methods, theories, statements etc. This procedure is, however, a version of the so called “naturalistic fallacy”, i.e. the logically invalid derivation of normative statements from descriptive ones. There is no reason that forces us to accept a given description of a scientific method as compulsory for other scientific enterprises. Further, since the entities – corpuscles, forces, fields etc. – that occur in scientific theories have been introduced in order to explain phenomena that had been observed and reproduced before the invention of those concepts, it is a petitio principii to regard the same phenomena as a proof of the literal existence of these entities. An example of this kind of fallacy is the widespread “proof” of the existence of atoms or molecules from the “fact” that the determination of Avogadro’s constant by means of various methods yields a reproducible numerical result. This argumentation neglects the circumstance that both the concept of corpuscle (atom or molecule) and Avogadro’s law have bee invested in advance in order to explain some chemical phenomena, and that the methods for the determination of this constant as well as the interpretation of their actually varying results as statistical fluctuations rely on this successful explanation. By the way, the definition of the objects of the sciences using concepts that have been introduced into theories in order to explain the properties of these objects or the phenomena that can be created with them, reveals a further weakness of the naturalist approach. For, since the explanations provided by the sciences are of empirical nature and thus prone to falsification, the definition of the objects of the sciences by means of these explanations is also susceptible to empirical revision. However, the objects of the sciences – e.g. bodies, stuffs, organisms – are also parts of pre-scientific situations and they have to be identified also by non-scientists. If this were not so, then scientific knowledge would not have any value beyond the boundaries of the research laboratory. With other words, there must be a method of identifying the objects of the sciences in such a manner that enables the communication between non-scientists and scientists before the latter begin with any research.
A further problem of the various naturalistic approaches is, that by abolishing the distinction between the “natural” and the “artificial” they also make the concept of nature itself void of any sense. On the level of moral considerations this blur has the unpleasant consequence of relieving man from the responsibility for the results of his actions, dooming him either to fatalism or to intellectual and practical inactivity.
In the course of the development of modern philosophy of science there have been some efforts to repair the problems of naturalism without giving up the programme as a whole. This has been done either by taking a more or less ad-hoc attitude towards the methodological rules of the sciences or by stressing the fact that sciences are sociohistorical phenomena depending on their past evolution and on the structure of the cultures they are embedded in. Ad-hoc positions have been either failed to achieve their targets like the efforts Carnap’s in his “Logical construction of the world” or they have been regarded as dogmatic both from scientists and from philosophers of science like Popper’s “Logic of scientific discovery”, because they could not justify the methodological rules they introduced. The reaction was the upcoming of the mentioned sociohistorical approaches like Kuhn’s paradigm-change-epistemology, the social constructivism, or the newly launched “historical epistemology”. Although all these positions offer important insights in the process of science, they share the flaw of being prone to the naturalistic fallacy because they try to derive normative issues from the descriptive analysis of the historical development or the social structure of science. Additionally they must also justify the use of the particular historical or sociological methods they apply and also ensure the validity of their results. Thus the problem of normativity in science is not resolved by them, but only shifted to the next level, where the carrousel begins again.
However, the emphasis on historical and social issues of science marks the transition to the culturalistic attitude against science, an attitude that establishes in advance a distinction between a cultural and a natural aspect of the world. The cultural aspect embraces all things, situations and processes that exist, take place or are initiated as a result of aim-guided actions of mankind in its various cultural contexts, while the natural aspect applies on those incidents that although not man-made, we are nevertheless forced to “endure” or to “observe” in order to achieve our aims. The cultural aspects of a bronze statue for example are the religious, aesthetical or perhaps political reasons that led to the decision for producing such an artefact, the actions for the carving of its form that are performed as part of a traditional practice of sculpturing, or the price of the material. The natural aspects are the fact that the statue material has to be produced by a given procedure from given raw materials, that in order to cast it, one has to heat it to a given temperature that cannot be altered by mere decision of the caster, the fact, that the statue under certain weather conditions will be covered by patina, that it conducts electricity and so forth.
Culturalism
The culturalist approach regards science as a man-made process serving the achievement of aims that are formulated in cultural contexts. The problem a culturalist philosophy of science has to solve, is then, how can science provide mankind with universally applicable answers if the questions are formulated in partially or totally incommensurable cultural environments, without taking into account a “natural connex” that trespasses cultural boundaries. Some variants of culturalistic philosophy just accept this situation an give up any attempt for a transcultural foundation of science. The very fact, however, that there is such a communication and that this communication is a desired one – even if this desire is neglected among some cultural contexts for various reasons – suggests, that there must be a method for establishing a consensus about scientific issues that transcends individual, social and cultural limits. Our suggestion is, that the transsubjective and transcultural establishing of the meaning of scientific terms can be done by recurring to actions that are needed for the achievement of aims in manufacturing (“poietical”) practices that are part of the everyday life in its various cultural contexts. All these practices, their elements and the knowledge that has been accumulated therein, are insofar primordial in respect to scientific theories, because they are experienced by both individuals and communities as being the “background of everyday activity”, and because there is no need of any scientific knowledge in order to become a part of them. The poietical practices constitute in each cultural context an area of practical experience that can be learnt by a novice by following the master’s instructions, or by repeating its actions.
Albeit culturally embedded, it is nevertheless possible to categorise the various poietical practices according to aspects that are common to them. It is the task of the sciences to provide theoretical knowledge about these “common aspects” of poietical practices, and it is the task of philosophy of science to find a method for the constitution of these aspects that can be transculturally accepted, and to elaborate the tools for the evaluation of scientific knowledge for its transcultural utility.
Summarising, we can formulate the task of such a philosophy of science as the rendering possible a transcultural “commitment without dogma” to the fundamental issues of the sciences by a step-to-step “methodical” reconstruction of their vocabulary and their theories, recurring to the actions involved in the achievement of their aims.
This outline of a “methodical culturalist” approach to the philosophy of science enables the definitive rebuttal of the claims that chemistry is a philosophy-barren land. Namely, in the everyday life there exist a lot of poietical practices in which altering of the “stuff” composition of things plays a more or less central role, either in the process of the fabrication of a thing, or as an aim of the practice itself. Especially in the latter ones – the so-called “stuff producing and processing practices”, methods and procedures are deployed that are independent from the methods of other practices, creating the demand for a science that is devoted to their theoretical sustainment – chemistry. Thus the general philosophical question about the constitution of the objects of the sciences can and shall also be stated for the special case of chemistry. On the other hand, since at the pre-scientific level the objects and the methods of the stuff producing and processing practices are independent from others, the objects and methods of chemistry are also independent from those of the other sciences, especially physics and biology. This statement does not deny the possibility of introducing physical and biological methods in chemistry – something that belongs to the present state-of-the-art of this science –, but it sets up a methodical order or methodical relationship between chemical, physical and biological methods, namely that the chemical methods are the ultimate standard for the evaluation of the utility of any other method for the resolution of chemical problems.
A further argument for an autonomous philosophy of chemistry is the fact that chemists label some chemical sentences with expressions such as “law”, “principle”, “theory” or “rule”. These expressions, however, are not chemical ones, but belong to a metatheoretical level, i.e. to the level of the speaking about chemistry. Their use in chemistry has to be justified according to criteria that have to be established separately in a philosophical discourse. And finally, the fact the chemistry has been preserved – at least in the last hundred and fifty years – from being involved in the ideological struggle between religion and science renders it in the position of being a “neutral” test and demonstration field for the “conclusions” of philosophy of science.
In the light of these arguments, the offer philosophy can make to chemistry is the elucidation of the provenance of the objects and the methods of chemistry as a cultural achievement by means of a methodical reconstruction of its language and its norms. For chemistry this is a bargain, because in our times the question about the constitution and the normative frame of this science has been – for good reasons – removed from the focus of the chemists, but problems connected herewith remain virulent and come to the surface every time when issues like the validity and the reliability of chemical analyses, or the relationship between function and structure of biomolecules, or the fail of chemical procedures during the transition from laboratory to technical scale, or conceptual problems like aromaticity are discussed.
Besides those “core effects”, a methodical reconstruction of chemistry would have also an impact on didactic of chemistry rendering the learning and the teaching of chemistry more feasible, would enable a better understanding of its history and would also help settle controversies in matters of science ethics and scientists’ responsibility.
Didactics
Even if the most primary level textbooks begin with the introduction of basic chemical terms recurring to activities of everyday life, atoms and molecules are “discovered” very soon, in order to provide the “explanation” of the phenomena. The situation worsens dramatically in chemistry textbooks of the secondary and the college level, where the importance of theoretical concepts like “atoms”, “molecules”, “chemical bond” and “structure” in modern chemistry has led many authors to an entirely axiomatic arrangement of their textbooks, setting those concepts at the beginning of the presentation of chemistry and not at the end, where they methodically belong in their function as explaining instances. Thus didactic of chemistry reproduces and transmits the naturalistic misunderstandings and misconceptions, relying on the authority of the teacher in order to ensure their acceptance by the pupils. In contrary, the methodically reconstructed chemistry begins with the familiar world of everyday life and introduces the specific chemical terms operatively, i.e. by creating the situation that is described by the given term, justifying at every step their relevance and adequacy. Thus the structure of the chemical theory becomes transparent and comprehensible.
History
Chemistry as a cultural achievement for the theoretical sustainment of stuff producing and processing practices has its own cultural history in the course of which it gained its modern contours. It is undeniable that the current chemico-historiographical research has made many invaluable contributions to the understanding of the various social, institutional, personal, political and also theoretical aspects that led to the raise of this science and determined later its further development, history of chemistry being admittedly one of the most proliferative branches of history of science. However, there is no profit without investment. Thus the success of modern chemical historiography relies on the existence of a “tacit” methodical “ground” that provides it with the “guidelines” for the interpretation of the chemical work of the past generations. Theoretical shortcomings that arise from these intuitively made “tacit assumptions” become visible, however, when historians of chemistry begin to reflect upon their own activity.
The results of a methodical reconstruction of chemistry can be utilised for the set up of a chemical historiography that seeks to elucidate the circumstances for the upcoming of chemistry as an autonomous science, and to work out the structures of the arguments the past chemists used for the justification of their terminological distinctions and their of theoretical conclusions, uncovering hidden methodical “ruptures”, argumentative circularities, anachronisms and “prothystera”. Central concern of a chemical historiography on a methodical and culturalistic basis would be the spatial and temporal determination of the genesis of the practically oriented chemist – in contrast to the natural philosopher of the antiquity and the medieval scholar – in the vicinity of the “chemical handicrafts”, working out the cultural conditions that enabled its appearance on the stage of history, and the adjacent exploration of the history of chemical ideas, concepts, institutions and of the various interconnections between society and chemistry.
Science ethics
A plethora of undesired environmental, social and political side effects and consequences of the explosive development of chemistry in the last fifty years kicked off an even increasing discussion on the ethical limits of chemical enterprise and on the responsibility of the chemists for the taming of the forces they have freed from their retorts. The importance of philosophy of chemistry for a fruitful discourse on these topics is easily illustrated on following example:
If a chemist sees himself in a naturalistic manner as a mere “discoverer” of the secrets of nature, like a miner who follows his vein in the earth not being able to influence its direction and yield, then, in the case he becomes aware that the knowledge he provides is more harmful than useful for mankind, he has no other choice than to cease his research activities on the particular field – to give up the mine. But with a culturalistic understanding of his activity as the production of knowledge for the solution of well defined problems, he is placed in a position that enables him to adjust himself to the upcoming conflicts and to search for a solution together with the people that are affected by his results.
The methodical reconstruction of the language of chemistry on a culturalistic basis consists of two main steps. First, the circle of those everyday life poietical practices has to be specified, that can provide the objects, the methods and the apparatus for the beginning of scientific activity, and that can gain a profit from the theoretical sustainment by chemistry. Such practices are handicrafts like metallurgy, tannery, pharmacopoeia, food-processing, charcoal burning, and industries like the petroleum refineries, the plants for the fabrication of dyestuffs, pharmaceuticals or plastics. They all share the common trait of being “stuff producing and processing” practices, involving methods like prospecting, mixing and separating, transforming or fermenting “stuffs” using various apparatus reactors, retorts, distillation apparatus, grinders, centrifuges and so on. The circle of practices that possess some of these traits makes up the so called lifeworldly basis of chemistry.
The second – more complicated – step includes a) the determination of the semantic function of the chemically relevant terms and their redefinition in such a manner that their meaning can be transsubjectively and transculturally ensured, and b) the formulation of norms for the performance of chemical actions, that enable the reproducibility of the relevant procedures and the comparability of their results in respect to the formulation of “chemical laws” and to the establishing of a systematic genealogy among the stuffs.
a) The principle of methodical order
The safeguarding of the transsubjective and transcultural meaning of the chemical terms is accomplished by observing the so called “principle of methodical order”, i.e. the prescription, that the linguistic definition of a term shall describe precisely the order of the actions that are needed in order to create the situation that the term under definition is referring to. The methodical order of the words has to follow the pragmatical order of the actions.
b) Semantic functions
In a typical scientific statement like „Measurements with the x-ray spectrometer revealed that the structure of the naphthalene molecules is that of two condensed benzene rings” not every word fulfils the same purpose and not every word is introduced in the same manner when a novice learns the language of a particular science. For our purposes we will not concern ourselves with words that occur in every sentence of our daily language – like ‘with’, ‘that’, ‘is’ although they are very promising objects for philosophical reasoning –, but we will draw our attention on words of special interest to a natural scientist, like ‘measurement’, ‘naphthalene’ and ‘molecule’.
The meaning of words like ‘measurement’, ‘condensed’, and ‘x-ray spectrometer’ for example is revealed to the freshman students of chemistry by example and counterexample. The teacher shows them which action is called ‘measurement’ or ‘to measure’, which apparatus is called ‘x-ray spectrometer’, which process is called ‘condensation’ or ‘to condense’, and controls the success of his effort by requesting them to perform the desired action, to name the apparatus or to describe the process. Those words that are used in order to distinguish and to describe actions, things, situations and processes have the semantic function of predicators.
If we turn now our attention to the manner in which words like ‘stuff’, ‘structure’, or ‘naphthalene’ are introduced, we will notice that it is not possible to establish their meanings ostentatively or imperatively. It is not possible to establish the meaning of the word ‘water’ solely by pointing to a pond and pronouncing “water”. What we see are liquid things called ‘pond’, ‘river’, ‘drop’, ‘the ocean’, but not water. On the other hand, sentences that contain similar words are not at all meaningless. From these examples we can see that there are words without reference in the above mentioned sense. Nevertheless, they have a meaning that is established by talking about things.
As second step in the reconstruction of the term ‘stuff’ and the stuff words we undertake a reformulation: Instead of saying “there is a chair made of wood” we can also say “there is a wooden chair”. Similarly we can substitute every stuff-noun by an appropriate stuff-adjective – although this is not common in contemporary English –, and still retain the original meaning of this sentence. Such appredicators are words that are used for the classification of things, i.e. they cannot be used alone-standing in a predicative sentence, although they refer in general to something, namely to properties of things. Again the reference problem arises here: Albeit appredicators like ‘red’, ‘rapid’, ‘heavy’ can be introduced ostentatively or imperatively, and hence posses a reference, this is not the case for our stuff adjectives. It is not a single referable property, but merely a property of a property that makes a thing wooden or ‘coppern’, namely the property of being homogeneous in respect to a number of properties. Being homogeneous means here that randomly cut parts of a thing match in a specific kind of properties. These properties that share the feature that a thing can be homogenised or be regarded as homogeneous in respect to them are its substantial properties. Examples for such properties are aggregate state (solid, liquid, gaseous), colour, taste, smell, the ability to give a sound when struck, hardness, density, inflammability, electrical conductivity, refractive index etc. Examples of non-substantial properties are shape, weight, velocity, or temperature. Things that are homogenised or regarded as homogeneous in respect to their aggregate state and to one of the other substantial properties are substantially homogeneous.
The final conceptual step from substantially homogeneous things to the talking about the stuff they are made of, is done by establishing an equivalence relation between substantially homogeneous things, the relation of being equisubstantial (this is the case when two substantially homogeneous things match in their aggregate status and in one or more other substantial properties), and by introducing an expression – ‘stuff’ or its synonym ‘substance’ – that denotes this relationship without taking into consideration the rest of the properties of those things. Statements about the stuff a thing is made of are true for every thing that is equisubstantial with it. Thus the concepts of stuff res. substance are not predicators but abstractors.
The procedure outlined here for the introduction of the concept of substance is an application of the general ‘constructive’ abstraction scheme that has been proposed by Lorenzen and has been recently refined by Hartmann. According to this scheme an abstractor is introduced in three steps:
Establishing of an equivalence relation ‘~’ with a range of values B.
Definition of an open sentence A(x) that is invariant (inv) in respect to ~ :
‘A(x)’, ‘~’ e inv =def Ùy, z. y ~ z ® (A(x/y) « A(x/z))
B(y) Ù B(z)
Conditional definition of the abstractor (|x|~):
A(|x|~) =def A(x) | B(x) Ù ‘A(x)’, ‘~’ e inv,
i.e. under the condition that A(x) is invariant in respect to ~, it is allowed to state for an object of B that A(|x|~) instead of A(x).
Similarly the stuff words ‘naphthalene’, ‘benzene’ etc. are introduced by establishing particular equivalence relations with definite values of the selected substantial properties. For instance, all solid things that are homogeneously of a white colour, have a crystalline texture, an average density of 0.9625 g/cm3, a characteristic smell, kill moths, and a melting point of 80.5 °C etc., are made of the stuff res. the substance ‘naphthalene’.
To this introduction of the term ‘stuff’ and the stuff words via the Lorenzen-Hartmann abstraction scheme (LH-abstraction) one could object that it is not adequate since it is bound to a given aggregate state. Everybody knows that water and ice consist of the same stuff although in two different aggregate states. Thus the definition of stuff seems to be underdetermined and the reference problem arises again. The answer to this objection is that the equivalence relation of equisubstantiality is indeed primarily confined to the aggregate state of the things considered. Ice, water and steam are three distinct stuffs. The circumstance that the equisubstantiality of water things can be restored, is a contingent fact. Our daily life world is filled with stuffs like honey, milk – even marble, or diamond – that cannot survive any change of aggregate state. And at any case this kind of persistence can only be determined after a reconversion to the initial aggregate state, i.e. we know that water and ice are the same stuff only because we can convert the one in to the other by raising and lowering the temperature. Albeit this ‘interconvertibility’ is an important feature for the selection of those stuffs that can be used for setting up a ‘substance genealogy’ in a chemical sense, as a property it is methodically secondary.
We have so far revealed the semantic function of words like ‘x-ray spectrometer’ and ‘naphthalene’, i.e. of predicators and abstractors. In our statement, however, we have still this ominous word ‘molecule’ that resists stubbornly any attempt to become subsumed under one of the introduced semantic functions. Grammatically the word ‘molecule’ is used like a predicator. We add, combine, split it, or determine its properties. On the other hand the object called ‘molecule’ is “invisible” but as we saw not in the same manner as a transparent, a very small or a hidden body. Furthermore the objects called ‘molecules’ do not occur in the life world. They are not something that we can buy in the market. Molecules occur only in scientific theories. Therefore we will call such an entity a theoretical construct. The words describing them have thus the semantic function of theoretical terms or theoretical concepts.
Theoretical constructs need not occur in every theory. Newton’s theory of gravity for example or Darwin’s theory of evolution are construct free. Even in chemistry there have been serious efforts to set up theories that explain chemical phenomena without the aid of theoretical constructs like atom or molecule. We will return to this later.
Some phenomena, however, cannot be explained just by establishing relationships between objects that are described with predicators and abstractors. A famous example for such a case – and by the way the cause for the introduction of the molecules in chemistry – is the law governing chemical reactions between gases. As early as 1808 Gay-Lussac found out that when to gases were brought into reaction their volumes, either as reactants or as products, always form ratios of small integer numbers. Chlorine and Hydrogen for example react to form Hydrogen Chloride in a volume ratio of 1:1:2, Oxygen and Hydrogen react to Water vapour in a volume ratio of 2:1:2 an so forth. Every gas reaction – a chemical phenomenon – is thus accompanied by a reproducible variation of the volume of the reactants – a physical phenomenon. On the other hand there are many reactions between substances in the solid and/or the liquid state for which this law cannot easily been checked experimentally because these substances cannot easily be transformed in the gaseous state.
In order to explain Gay-Lussac’s law, the theoretical construct
molecule has been introduced in the chemical theory. The chemists assumed that the “matter” of a given chemical substance is not homogeneously distributed in the volume that this substance occupied but that it forms small corpuscles, the molecules. The result of a reaction can now be interpreted as if the molecules of the one reactant are combined with the molecules of the other. Thus one molecule of Chlorine is combined with one molecule of Hydrogen to form one molecule of Hydrogen Chloride. Because a reaction is a chemical operation under controlled conditions, it has to be performed according to the norm of the constancy of mass and the norm of the constant proportions, i.e. the sum of the masses of the products of the reactions must be equal to the sum of the masses of the reactants and the products must show constant composition. Hence equal volumes of two gases must contain equal numbers of molecules. This would mean that one volume Chlorine gas and one Volume Hydrogen gas should produce one volume of Hydrogen Chloride gas, what is not the case. So it was further assumed that the molecules of Chlorine and Hydrogen are split during the reaction into “molecule halves” that recombine to form the molecules of Hydrogen Chloride. In our modern chemical terminology these “molecule halves” are the theoretical constructs atoms.
Let us now recapitulate the function of the theoretical constructs atom and molecule in the explanation of gas reactions:
In a gas reaction a reproducible chemical effect (the reaction) takes place together with a reproducible physical effect (changes of volume).
The theoretical constructs molecule and atom help us to integrate both phenomena in one theory providing thus a good explanation for gas reactions.
In order to check the validity of Gay-Lussac’s law for substances that cannot be vaporised easily the theoretical constructs molecule and atom are provided with theoretical properties like “atomic” and “molecular mass”, “atomic valence” and “molecular structure” – the latter being introduced by establishing an equivalence relation between theoretical constructs and geometrical forms!
Since its formulation in 1811 by Avogadro the modern molecular hypothesis has been proven very successful in explaining and integrating chemical phenomena and also in enabling the prediction of yet unknown ones. It has therefore gained a firm place in the chemical theory. The clarification of the semantic status of ‘molecule’ and ‘atom’ as theoretical concepts of the chemical theory explains also why we did not take up their use in ancient, medieval and early modern philosophical theories like the doctrines of Democritus, Lucretius or Gassendi or the chemical theories of Newton and Dalton.
The corpuscular chemical theories developed by Newton and his contemporaries in the 18th century are very interesting both from a historical and a philosophical point of view. They have been formulated in order to give a theoretical explanation of chemical phenomena using theoretical constructs in the sense reconstructed here. However, the explanation at that time for the chemical affinities of the substances relied on Newton’s gravitational theory that could give an account for the attraction between the molecules but was not adequate for the explanation of the particular affinities between given substances. This fact, in combination with the lack of a normative frame for the performance of chemical reactions and the definition of the term “chemical compound”, resulted in the rejection of the “gravitational” chemical theories by the beginning of the 19th century. The atomistic ideas of J. Dalton who is sometimes regarded as the “Father of the atomic theory” are also localised in the realm of natural philosophic speculation, because he does not give any reason neither for the laws of atomic combinations he formulates nor for the validity the deductions he draws from them about the qualitative composition and the molecular mass of chemical compounds like water, ammonia, nitric acid, or carbon dioxide. The consequence of these failed efforts for a corpuscular explanation of chemical phenomena was that the introduction of these theoretical constructs in chemical theories was discredited for a long time. Even the above mentioned successful corpuscular explanation given by Avogadro for the chemical and physical phenomena accompanying the reactions between gases did not manage to overcome the reservation against the atomistic chemical theories in chemical circles, a reservation that persisted until the beginnings of our century. Among the most convinced representatives of this anti-atomist or anti-corpuscular party have been the 1905 Nobel laureate Wilhelm Ostwald and the today lesser known Czech chemist Frantisek Wald who in contrast to Ostwald opposed the atomic theory until his death in 1930.
c) Norms
Norm of the conservation of mass
The scientific request for a frame allowing the comparison of the efficacy and ensuring the transsubjective performance of substance transforming procedures, results in the formulation of the norm of the conservation of mass. This is the prescription that a stuff transformation shall be performed so that the mass of its products equals the mass of its raw materials. A transformation that complies with this norm and the products of which are chemically pure substances is called chemical reaction. Violation of the norm of the conservation of matter is an indication that either there are products that undetectedly escape from the reaction vessel, or that there is an unknown substance that enters the reaction. The violation of this norm must not be interpreted as the empirical proof of the transformation of matter into “energy” or of its “ex nihilo” generation.
Norm of constant proportions
One of the main tasks of chemistry the classification of the chemical substances and the establishment of “genetical” relationships between them. For this purposes we need a criterion for distinguishing the components of a substance that are relevant for its chemical composition from those ones that are only incidentally among the products of its chemical decomposition. Therefore we have to formulate an additional norm, the norm of the constant proportions. It states that chemical reactions are to be performed so that their products are chemical substances having constant composition, i.e. their components must show constant proportions.
As a resume of the project of a culturalistic philosophy of chemistry, we can state that its aims are the methodical constitution of the objects, the foundation of the basic terms and the formulation of the necessary norms of this science in respect to the actions that are involved in pre-scientific poietical practices in order to change the substantial properties of things. The philosophical methods that are utilised for performing this task are the determination of the semantic functions of chemical terms, the application of various procedures of philosophy of language, like the imperative and the ostentative introduction of predicators, and the abstraction procedure for the introduction of abstract terms, and the method of operative definition for the establishing of the meaning of equivalence relations avoiding thus indefinite regresses or a violation of the principle of methodical order.
From this description of the main issues of a culturalistic philosophy of chemistry, the role of modern philosophy in its relationship to science emerges in a new light. Philosophy is neither the teacher of dogmas that are imposed on science, permitting or forbidding the acquisition of knowledge with the one or the other method in this or the other area. Nor is philosophy ancilla scientorum destined to deliver ex post legitimisations for laboratory made decisions that have an impact on society. Between philosophy and the sciences in general, or more specific, between philosophy of chemistry and chemistry exists rather a relation of partnership and division of labour. While chemistry operates at the frontiers of knowledge acquisition sustaining the practices that provide mankind with the substantial means for satisfying its everyday needs and perhaps improving its quality of life, philosophy acts on the background founding and evaluating the linguistic tools that chemistry uses for the organisation and communication of this knowledge, and making aware of the fact that man is the originator of the aims, the objects and the methods of chemistry and thus the beneficiary and the victim of his own actions.
Top - Home - CV - Research & Projects - Teaching - Preprints
Version from