The value of Historical Concepts in Science Education
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There has been a tremendous thrust by educators in recent vears to modernize the methods and devices through which chemical concepts are presented to students. The directions, as I have surmised them, lie largely in the development of more efficient, more digestible ways of acquainting students with chemical concepts and techniques, which should ultimately better equip them t o approach new problems "creatively," or in the case of nonmajors, to at least provide them with some cultural appreciation for the science and its role in society. I think that efforts toward such curriculnm-streamlinine measures as the dissolution of artificial distinctions b& tween the various branches of chemistrv are excellent and should be f.eriously considered a t most colleges. Also, the value of modular units for oresentine - certain conceots and problem-solving techniques such as stoichiometry and dimensional analvsis is incontestible, and in these matters should probabl; receive universal implementation. The position I wish to adopt here, however, is rather that of the Devil's advocate, in being partly antithetical t o such streamlining and compartmentalization in the presentation of an empi&al science. The reason for my assuming this position is that no science can be treated simply as a collection of facts, concepts, and procedural rules,-hut must also be considered within a vast framework of methodology and epistemology that has evolved over the centuries that man has undertaken scientific enterprise. The aims of instruction in any science should include (a) an introduction to the domain or concerns of that science, (h) the kind of methodology used hy that science, and (c) an epistemological perspective by which to evaluate the information eenerated bv that science. These are not to be construed as self-delimiting categories, but should each be considered in some wav in develooina the subiect matter for the course. That is; the doma& of chemistiy concerns the world of inanimate matter, and its aims are to understand the substantial nature of this world, its properties, and interrelationships. The methodology of chemistry (or any empirical science) involves two phases, discussed a t length by F.S.C. Northrop.' The first is a "natural history" phase in which empirical data appropriate to that science are collected, described, and classified. Included in this phase would be the specific techniques used by that science in the acquisition of these data. The second is a theoretical phase in which a body of principles and concepts is generated to explain and unify the diverse empirical data generated during the natural history phase of the science. Therefore, part of the methodology of any science involves the postulation of certain intangible, unobseruable entities (phlogiston, "ether," atoms) in order to account for the various tan~ible.obseruable ehtities that form the subject matter for that science. Northron considered these ohases in the develooment of a science to he separated temporally as well as procedurally, hut they seem to really occur concurrently. Empirical data suggest hypotheses, and hypotheses suggest new ex~erimentation,so that scientific understanding progresses dialectically as a result of this tension between the two ~ h a s e s .Thus, the notion of the "atom" was developed by Greek philosophers, particularly Democritus, in order to
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Journal of ChemicalEducation
provocative opinion account for certain basic physical observations, such as the many and varied forms assumed by matter, the diversity of the& properties, and their alterability by specific treatments, such as fire. Its postulation also seemed to be necessary to account for an equally basic philosophic problem, namely the occurrence of change and motion in the world. Much later, as quantitative techniques began to he applied to the study of chemistry and more empirical data became available, Dalton revived the atom as an explicatory concept to account for the observation that elements combined in certain definite proportions by weight. The Daltonian atom was, of course, significantly different from the Democritian version. and was a vastlv more powerful, quantitative concept by which to explain chemical phenomena than its predecessor had heen. The point is that its existence in both cases had been "guessed at," proposed soeculativelv (albeit with solid evidence in the latter case), r k h e r than-proved. Chemical and physical properties were explained by the Greek atomists as owing to certain specific geometric shapes of their atoms which allowed them to interact anri combine in particular ways. We are now convinced that other theoretical entities called electrons provide the hooks through which chemical comhinations occur. This has turned out, with the progressive refinements of atomic and molecular orbital theory, to he a very powerful and fruitful way of explaining the properties of chemical substances. The thrust of this argument is that science never eets anv final answers about. for examole. . , what matter "is," hut proceeds through a tension of empirical fact and theoretical construct to oroeressivelv more . powerful and general ways of explaining its behavior. This constitutes the eoistemoloeical framework referred to a t the beginning of this It is important that students get some feeling for the "movement" of science and be able to clearly &stiuguii6hetween empirical and theoretical entities. A quartz crystal is unaualifiedlv real. I t can he apprehended immediat&y by the senses a s having certain qualities of shape, hardness, color, density, refractive index, etc. This is the starting point for scientific enquiry, and it is important that one does not accord the same reality status to the silicon dioxide tetrahedra which we propose to account for the qualities of quartz enumerated above. Regardless of the power and consistency of their predictive value, these tetrahedra must still be regarded as theoretical entities, whose reality remains tentative and contingent on experimental evidence. Clinging to such theoretical constructs as "caloric" and "phlogiston" as though they possessed concrete, independent existences has always resisted the dialectical progression of scientific understanding. T o assure students that electrons (or even atoms) are "real" in the same sense that an object or a measurable phenomenon is real is t o strip away the dialectical method from physical science, leaving i t a body of information, principles and procedures that can be mastered and applied to the solution of certain technological problems. This is certainly part of science; the present state of the art should clearly be made available to students. However, such matters as atomic structure, whose concepts have evolved slowly and subtly over the years, should not be presented in the beginning of an introductory chemistry
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course as "given" or as unambiguously demonstrated by certain experimental observations. Yet this is frequently done. in order to nrovide conceotual tools for the i m ~ o r t a n t discussion of chemical bonding. The philosophic objections I have t o this approach were crystallized succinctly for me in Professor Hammond's recent article2 in which he relates a articular student's indienation and confusion about heing taught different versions of atomic structure in successively more advanced courses. Why, the student asks, was he not simply taught the right version in the first place? Part of the difficulty, which we mistakenly hide from students, is that there is no "right" version. Some versions have greater generality and more quantitative power than other versions. The wave functions used in the "best" calculations are approximations based on the hydrogen atoms and can make no claim to heing "real". The Italian philosopher, Vico, is reported to have said that our comprehension of the material world is necessarily limited and imperfect, because we did not create it.3 We cannot create matter, and we have no understanding a t all of its essential properties such as gravitation and electromagnetism. We can merely describe the phenomena and the conditions under which they occur with certain quantitative laws. Mathematics, as Bertrand Russell points out,3 is entirely a creation of the human intellect. Its relationships are clear and follow necessarily from specific definitions and axioms. One can completely understand, then, a suhject like Euclidean geometry in a way that is not possible to do in a discipline relying on external entities that one encounters in the physical and social sciences. (On the other hand, one must not assume that the axioms of Euclidean geometry are self-evident, a priori truths that must necessarily apply t o the real world.) Thus, there are epistemological problems in science that one does not encounter in mathematics. In a sense, the mathematics student is able t o recreate his subject in the act of doing proofs and solving prohlems. A final understanding of Nature's laws, on the other hand, may indeed
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Northrop, F.S.C., "The Logic of the Sciences and the Humanities," World Publishing Co., New York, 1959, pp. 133-167. Hammond, G.S., J. CHEM. EDUC., 51,559 (1974). 3Russell, Bertrand, "Wisdom of the West," Crescent Books, Ine., New York,1960, pp. 206207.
he impossible, and our uodentanding of these laws a t any instant in history is necessarily tentative. I t is my opinion, then, that topics such as atomic structure should he carefully presented so that they d o not assume immutahle shapes in student's minds. Chemistry has enjoyed a prolonged "natural history" phase due to the world's tremendous compositional variety. This phase is largely completed now, and i t is tempting t o present i t in a package along with the current status of its explicative principles and theories. This might, in fact, he useful in the short run for imparting to the student a technological feeling for his suhject. But if we present physical theories as "proven," instead of indicating the organic, dialectical nature of their development, we might encourage students in the long run to respond somewhat rigidly and unimaeinativelv to new Drohlems and new empirical data. Perhaps it is imprncticnl tu mix these historirally developed concepts of scientific method with such topics as swirhiometry in an introductory chemistry course. If this is 90, then perhaps separate courses in the history and methodology df science ihould be required of science majors and taken concurrently with the standard offerings. As i t is, we are not presenting the whole picture to these students. The same general comments apply to those science courses desiened for liberal arts students. These students frequently assume the philosophical position that physical science is mainlv a collection of techniaues for mani~ulating the environment in the production of a technology that seems to run autonomously, polluting the waterways and poisoning the air, which they rightly regard as heing alienatine and dehumanizing. Certainlv, to acquaint students witLsuch topical concerns and prbblems df technology as "ecolo~v." "~ollutioncontrol: and "the energy crisis" is useful&d important, and might he an ameli&ant to this attitude. I also feel this problem can be addressed hy providing courses which emphasize the historical, philosophical, development of scientific concepts, not simply their current applications. No liberal arts education can he considered complete if i t does not include an appreciation for the historical unfolding of scientific thought, which, in my opinion, is the greatest cultural expression of Western man. ~~
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Jeffrey S. Wicken Behrend College of The Pennsylvania State University Erie, 16510
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