provocative opinion Does Theory Ever Become Fact? Charles M. Wynn Eastern Connecticut State University, Willimantic. CT 06226 Recent breakthroughs in the field of microscopy have nrovided strikine evidence for the annarent realitv of Htoms. In the 19%'s, field ion m i c r ~ s & ~ ewere s usek to pmvide images of gas atoms striking a fluorescent screen. In 1976, scanning electron microscopes were used to produce motion pictures of the thermal motion of uranium atoms. With the development of a new family of microscones. scanned-nmbe microscones. such as the scanning tunneling microscope develop& in 1981 and the atomi; force microscope developed in 1985, direct observation of particles with properties consistent with theoretical expectations of atoms has a t last been achieved (1,2).Such devices are even capable of resolving features that are only about a hundredth the size of a n atom. Now that atoms have been observed and direct evidence for the shape and location of atoms has been obtained, should the Atomic Theory be considered completely factual? The Nature of Science An answer to this question must be given in the context of the nature of science. Science, the study of natural and artificial phenomena in the universe with the aim of understanding them in a general way, begins with observation of phenomena. f i r sufficient observations have been made, a hypothesis or general statement about the basic nature of the hen omen on observed is formulated. This hypothesis shduld be as general as possible to deal with other phenomena besides the specific ones observed. It can thus be used to predict phenomena. Experimentation is the test of the prediction: did the phenomenon occur as auticipated? If it did, the hypothesis upon which the prediction was based gains credibilitv. If it did not. the hvuothesis must be discarded or moiified to a c c o ~ m o d i i ethe results. To illustrate this approach, consider a student assigned to a room in a college dormitory. On the first day of classes, while still burrowed beneath blankets, the student can observe with his or her sense of hearing that the occupant of the adjoining room leaves the room a t 6:00 a.m. &d then returns out of breath a t 7:00 a.m. ARer observing this behavior several days in a row, the student formulates a descriptive generalization of the behavior: the neighbor always leaves the dorm a t 6:00 a.m. and returns at 7:00 a.m. out of breath. Ahypothesis in the form of a descriptive generalization is usually called a law. In this example it might be named the Law of the Next Door Neighbor's Early Morning Behavior. One could then make a nrediction based upon the law: this individual will leave t6e room tomorrow at 6:00 a.m. and once again return a t 7:00 a.m. out of breath. If the actual behavior or experiment is consistent with the nrediction. the hvuothesis gains credibilitv. If ". not, i t must be revised. For example, the next door neighbor's behavior mav be limited to weekdavs. 0-nce the law has been established, one could seek to explain the regularity of the behavior. A hypothesis in the
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form of a n explanation is usually called a theory In the examnle. one theow mieht be that the next door neighbor is a h'ealth enthusiast c h o behaves that way to staylfit by "ioeeine. This might be called the Theorv that the Next Door Geighbor ~~a Health-Conscious ~ o g ~ eThe r . theory predicts the observation of this neighbor jogging between 6:00 and 7:00 a.m. Until such a sighting is made, other explanations such as tennis playing, newspaper getting, etc., could also be considered. A theorv also can take the form of a model, a representation of reality invented to account for o b s ~ ~ e d - ~ h e n o ~ ena. Model formulation is a n attempt to provide a visualization or analogue that helps one bette; understand the nature and interactions of the entities involved in the phenomenon. In this example, one might envision the neighbor dressed in jogger regalia-a sweatband, sweatshirt, sweatoants. and "ioeeine shoes. This could be called the ~ogge;~ o d ofh the neighbor. The same reasoning process is used by chemists. For example, after numerous determinations of mass relationships in chemical reactions, chemists formulated the laws of Conservation of Mass, Constant Composition, and Multiple Proportions. To explain these laws, they proposed the Atomic Theory, which postulates entities known as atoms.
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Limited versus Universal Theories What is the status of a Jogger Model or a n Atomic Theory once the postulated entities (joggers, atoms) are actually observed? If the next door neighbor is observed to be a jogger, the Jogger Model takes on the status of fact only for that particular jogger. While other individuals who leave their rooms at 6:00 a.m. and return a t 7:00 a.m. out of breath may also be joggers, still others may be tennis players, newspaper getters, or even previously unimagined types of individuals. A theory regarding a single jogger is a limited theory, limited to a particular phenomenon. The sighting of one or even many such joggers does not mean thateverj early rising, out-of-breath individual is also a jogger. ~ v e nthough atomic theory has been able tn explain the behavior of all matter studied thus far, and, even though in all samples swnned by microscopes, the existence 07 the postulated atoms has been verified, it must be considered i t least conceivable that entities other than atoms mieht be discovered, particles which also explain the laws of Conservation of Mass. Constant Cornnosition. and Multinle Proportions. scientific theories can Lever become scientific facts. because a scientific theorv deals with all instances of a phenomenon; i.e., it is a universal theory. While the behavior of all matter may indeed be explained by atomic theory, there is no way of being certain that this is the case. Such is the open-ended nature of science.
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Literature Cited 1.Binnlg, G.: Rohrer,H. Sei.Amer 1986,253121,5&5€. 2. Wiekramaainzhe, H.Sci Amen 1988,261141, 98-105. Volume 69 Number 9 September 1992
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