PROBLEM SOLVING: METHODS AND PEOPLE 329 argue that the screwdriver is better than the hammer would clearly be ri- diculous each is uniquely suited to perform certain tasks. Such is also the case with the tools available for problem-solving. First, let us consider the theoretical approach. Here, facts are fashioned into a theory, which must be proved by a carefully designed experiment. The experiment in turn produces more facts which may make it necessary to modify the theory and thus necessitate further experimental proof, and so on. Workers in this field often use mathematical language to represent their models. The recent tenth anniversary of the tragic Texas City dis- aster is a reminder that the cause of the ammonium nitrate explosion was determined by the model-building technique. The theoretical approach is essential here--after all, one can hardly go around exploding enormous quantities of ammonium nitrate in order to get additional data. A more recent and highly successful application of this method by scientists skilled in Operations Research is the calculation of physical constants and other engineering data for complicated piping networks. Complex "plumbing" problems may now be solved on a computer, instead of by an army of en- gineers carrying out dreary mathematical calculations. In this case, a problem which has already been solved has been resolved by a far more ele- gant method. This is a familiar pattern--many current problems being handled by the experimentalists may ultimately be resolved more rapidly and accurately by the model-builder, using the evidence accumulated by the experimentalists. The model-builder is sometimes compelled to resort to the empirical ap- proach. A good example of this is in the identification of materials by IR absorption spectra. Although the theory is highly developed and the in- struments very refined, the model-builder cannot positively identify a ma- terial from theoretical considerations. He must be able to compare his spectra with that of a known and closely related, or better still, identical, compound. Scientists engaged in this sort of work are usually highly trained, articu- late people who like to talk about what they do. It is probably fair to say, however, that they are much more interested in discussing their methods than their results. The extreme case of the model-builder is the scientist who is so preoccupied with his method that he selects his problems in order to provide opportunities to use his technique. At the other end of the scale, there is a gradual, almost imperceptible, change into the predominantly ex- perimental area. For instance, who can judge where the field of the poly- mer scientist ends and that of the advanced resin chemist begins ? The experimentalists' method for solving problems is perhaps the most familiar to industry. It can accurately be described as an empirical method, although this is a dangerous word because it has become identified in many people's minds with an approach which is dependent only on experi-

330 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ence and observation, and is not scientific. This is most unfortunate. It is true that the empirical approach is based on experiment or experience, but in gathering his evidence, the experimentalist must be guided by scien- tific principles as rigid as those recognized by the model-makers. In a sense, every individual experiment which the experimentalist carries out is, or should be, an exercise in theoretical scientific problem-solving on the micro scale. By the nature of his work, however, the experimentalist is often unable to see far ahead. He must feel his way carefully from experiment to experiment, gingerly probing for profitable areas to explore. This kind of work is costly and time consuming it is, therefore, vitally important that the experimentalist should not only know how to do his work, but, still more important, he should know what to do. A worker who has the reputation for solving problems of this type quickly does not arrive at the solution by some magical process or just plain luck. His success is attributable to his intuitive ability to decide which is the most profitable experiment to do first. The experimentalist should be aware of the danger involved in the misuse of this technique. Just as the model-builder may lose his power of contri- bution by transferring his affection from the problem to the method, so the experimentalist can become a liability if he neglects scientific principles. Many a research director has become prematurely aged on being presented with a long series of experimental results without a "control," and the failure to recognize an important variable such as humidity, is another favorite pitfall. The experimental technique is, of course, uniquely suited to many in- dustrial problems. Workers in this field often deal with natural materials, with complicated resins, with blends and mixtures in which the components interreact in surprising and unpredictable ways. Although we have, for instance, a tremendous background of literature on the behavior of such materials as rubber, proteins and cellulose, I believe that workers in these fields would agree that we are not yet ready to tackle many of the problems of modern industry by the extensive use of theory. What of the experimentalists themselves? Perhaps, on an average they have not received the high degree of specialized training associated with the model-builders, but their experience is broad. They are generally practical minded, and their first impulse on tackling a problem is to get out into the laboratory and get started with some experiments. As a group, they com- municate less readily than the model-builders, both with their fellows and with people outside of their sphere. They are inclined to talk in terms of the feel, the smell, the look of a material rather than to show how nicely it fits into a theoretical framework. The experimentalist talks more about his results, and less about his technique. While every experimentklist fondly hopes that theoretical conclusions will ultimately be drawn froth his