ON THE HORNS OF THE SACRED COW' ANTHONY STANDEN The Interscience Encyclopedia, Brooklyn, New York W m T is it t,hat me teach? Chemistry, presumably. And what is that? A science. And a science is an organized body of knowledge. Not just any organized body of knowledge (such as, for example, the law) but a n organized body of knowledge obtained by the scientific method-and here I invite any chemist to give his own definition of "scientific method," for I am not going to define it, but will rest content with the fact that all definitions of the scientific method have, at. any rate, a great deal in common. But what, are we teaching, the knowledge, or the method? The two are by no means the same, and we could teach the method, or we could teach the knowledge obtained by that method. These are the horns, and it should be noted that it is necessary to progress fairly far along both horns, for to teach a method without knowledge is meaningless, and to teach facts without scientific method is to make science indeed a Sacred Cow. When I look a t a course in chemistry, or a textbook, I get the impression that it consists almost exclusively of facts--of various bits of the knowledge that has been obtained by the scientific method. But as for this method itself-well I invariably find a little pep talk about it in Chapter I, or else in the introduction, but t,hat's about all. The main content is always facts, facts, facts. When I turn to the purposes for which a course in chemistry is taught I find a rather curious situation. A course in chemistry may be either for chemists, or else for nonchemists, for whom chemistry is to be only a part of their general education. Now, one would naturally suppose that the chemistry majors, the specialists who intend to be professional scientists and aregoing to use chemistry in their life work, would need very careful training in the scientific method, whereas this would not be so necessary for the liberal arts stu-
dents. They are not going to be scientists, and one might suppose that they would not have much need for the scientific method. They are not going to be engineers, and they certainly will not receive much training in the engineering method, neither is it considered necessary to train them in the "legal method" (if there is such a thing) or in any of half a dozen other'lmethods" that one might name. This might be one's off-hand judgment, that the professional scientists would need to know the scientific method, whereas the others would not. But it is quite otherwise. Any apologist for chemistry as part of the curriculum of liberal arts students always stresses the importance for these people of some aquaintance, even if a very nodding one, with the scientific method, whereas anyone engaged in the training of professional chemists is compelled to teach them facts in such enormous profusion that the amount of attention devoted to scientific method, as such, drops, percentage-wise at any rate, to a very low level. One can look a t the matter in another way and obtain the same result. What do chemists do after they graduate? Apart from the percentage who, after majoring in chemistry, go off into some other line of work, those who remain in the field-what do they do? Some of them go into the plant and become plant chemists, perhaps even chemical engineers. Some of them go into the sales department, and rise to be vicepresidents. Some of them go into advertising, or publicity, or other forms of work that can be done at a desk. Very many of the graduates will be found, twenty years later, not to have been inside a laboratory for twenty years. And yet they are still practicing chemistry, inasmuch as their work depends on a knowledge of chemistry. Note that it depends upon a knowledge of facts. It does not depend upon a knowledge of the scientific method, nor on any ability to practice it, and I suggest that many of these people know nothing ' Presented at the 13th Summer Conference of the New England Assoointion of Chemistry Teachers, University of Rhodo of the scientific method except what they learned by hearsay in their early college days. Island, August 23,1951.
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On the other hand the nonchemists learned far fewer facts in their college chemistry course, and they forget a higher percentage of these facts sooner, so that unless they are taught a little about the scientific method what on earth does remain when they are twenty years out of college? A similar conclusion results from yet another approach. Why do we make laboratory work a part of the chemistry course? I am not asking whether we should make laboratory work a part of the course, because the answer to that question is an unqualified yes. I am asking for detailed consideration of exactly what it is that we are trying to achieve in the laboratory work. First, let it be noted that we are not giving laboratory exercises in order that the students shall have the ability to do laboratory work. Only a small proportion of the students will continue to do laboratory work for more than a short while after they finish their training, and the insistence with which we give laboratory work to everybody shows that we must have some idea in.our minds other than training all to be laboratory operators on the off chance that just a few of them will actually use this ability. The easy answer to the question, "Why do we insist so much on laboratory work" is "To give some practice in the scientific method-of course." I think that this is a loose and ill-thought out answer. Does laboratory work actually teach scientific method, or have any close relation to it? Yes and no. It all depends on what you really mean by the scientificmethod. And now I find that I do have to define that method, or a t least clarify its several meanings, after all. I will do i t by the method of induction, taking several particular cases, seeing where they fall, and then seeing if we can arrive a t a generalization about what in and what is not scientific method. First of all, I would like to say that I do not think that determining a melting point can be called an example of the scientific method. It is an example of the use of a thermometer, of a Bunsen burner and a melting point tube, and it is a good example of the necessity of accurate observation. But that's about all. For, according to any definition, the scientific method comprises not only accurat,e observation, with measurement, but also the forming of hypotheses and the testing of the hypotheses by further experiment. But does the determination of a melting point involve the testing of a hypothesis? Again, the evasive answer, yes and no. Before pursuing this elusive scientific method any further, 1 would like to say something about why we insist so strongly on students actually carrying out laboratory experiments. I t may well be that my present train of thought will lead me to conclude that hardly any of the regular work of a teaching laboratory is scientific, but, even if t,his melancholy conclusion should he reached, I would like to make it clear that the case for having students work in the laboratory, manipulsting the apparatus themselves, is not in any jeop-
ardy. We have a cast-iron water-tight case for insisting on laboratory work, whether it is scientific or not. The object of laboratory work, I suggest, is t o permit students to know what we are talking about. Without actual work in the laboratory, the most amazing misunderstandings are possible. All of you teachers must have seen innumerable examples of this, but for amusement I will tell a story from my own experience. I n England, Imperial Chemical Industries, Ltd., for whom I worked, had the idea that the bright young men, nonchemists, in the London office, could profit from brief trips to the manufacturing plants where the chemicals that they dealt with were actually made. In my branch of the great combine we were not allowed to take these young men into the plants, because we were bound to the utmost secrecy even within the company by what was known as the "Solvay agreement." I had to tell one of the young men how sodium cyanide was made. I explained how sodium, charcoal, and ammonia were all heated together in a pot. I don't known what kind of a pot the young man had in mind, but I'm sure he thought we put in the ammonia with a spoon. "What does cyanide look like?" he asked, and I told him it looked rather like sugar. "I see," he said, and wrote down in his note book "brown sugar.',' I hadn't said "brown" and I meant white sugar-but he had a knack for getting things wrong. The young man was then handed over to a chemist from the sodium plant, to 6nd out ~vherethe sodium came from. The chemist explained how electrolysis of sodium hydroxide gave oxygen at the anode, and both sodium and hydrogen at the cathode. The young man then asked an intelligent question: "How do you separate the sodium from the hydrogen?" But the chemist from the sodium plant had little sympathy with ignorance, which he mistook for stupidity; he pulled a very long face and said "Ah! That's covered by the Solvay agreement." If you don't know what sodium and hydrogen look like, then it is a sensible question to ask how they are separated. And what does hydrogen look like? One can't see it. One can only see the glass apparatus, and the mercury or water that is used for confining it. If beginning students don't handle apparatus themselves, or at least see someone else do demonstration experiments with gases, they are apt to he totally confused as to what a gas is. This particular misunderstanding, of not knowing what a gas is, or what water is like when it boils, is for elementary students. But even for more advanced students laboratory work must be carried out for similar reasons. Without doing a steam distillation, there can be an abject misunderstanding of what "steam distillation" means. Quite an advanced student might easily say, "Beilstein gives the melting point of this substance as 5.4"C., but the author of a paper I am reading says he cot 5.5 as the meltine ~ o i n tso . they can't be talkine about the same thing." A very littlk experience with u
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melting point determinations below room temperature would show him how easy it is to he wrong by one-tenth of a degree. The same student might say, "One author has a gas of refractive index 1.00000132, while the other's is 1.0000073, there's hardly any difference between the two." If he had any practical aquaintance with the property in question, he would realize that t,he first digit is not significant, and the two gases really differwidely in refractive index. I suggest that this is the true reason why we all feel that laboratory work is absolutely necessary. I t is simply so that the students will know what chemistry is about. I can imagine a student, brought up on the Br@sted presentation of acids and bases, wanting to acidify a solution and looking around for a reagent bottle labeled H30+. I am reminded of a member of the I.C.I. purchasing department, who is said to have designed a 2-lh. package by taking each of the dimensions of a rectangular 1-lh. package and doubling themgetting an 8-lh. package; and of another who ordered a gross of acid eggs. Even quite advanced students must have actual experience of the things they are talking about, or they will make the most hopeless mistakes. But is all this science? Is determining a melting point to he distinguished from a thousand empirical determinations that everybody, scientist or nonscientist, makes every day of his life, things of the order of: "Is this ruler too long to go into this box? Try it and see." If the test is that science depends upon making. hypotheses and confirming them by experiment, then we have to he careful mhat we mean by hypothesis. To measure a table is not to make the hypothesis that it is four feet long, then that it is five feet long, and then six and so on until we get it right. If hypothesis means that kind of thing, then the term is far too broad, because almost anything is a hypothesis. We have to restrict the meaning of this term, or we will get a meaningless definition. As a way of restricting the meaning of hypothesis so that it does not blow up in our faces, I suggest remembering that science is supposed to deal ~ i t generalities. h It is not science to measure the length of chis table, the height of this chair. There must he an element of generality, so that when a measurement is made, the result is a constant of nature, something that is the same for everybody, and stays put for all time. If a new compound is made, and if it is found to have a melting point of 22.2'C., this has some generality, for the same compound is always the same compound, and the melting point is a constant of nature. Therefore this is an example of the scientific method, at any rate in one sense, although this is probably the lowest of senses. What about a determination in qualitative analysis? If we determine that. this solution contains zinc ion, have we used the scientific method? Certainly not in the same sense as before. There is nothing general
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about this solution, it is a specific one. I t is merely "solution A" in the course a t this particular institution of learning. It is not the same for everybody and is not a constant of nature. I conclude, perhaps somewhat severely, that practical work in qualitative analysis is not an example of the scientific method. I t corresponds to measuring the length of chis table, with only the difference that the operation of measuring a table is exceedingly simple, whereas the operation of testing for zinc ion depends, for anything like a full understanding, upon a considerable amount of knowledge which was originally determined by other people, by the use of genuine scientific method. What about quantitative analysis? One of t,he distinguishing marks of any science is that, wherever possible, it makes quantitat,ive determinations. I am afraid I cannot allow that this quantitative aspect is enough to make a determination in "quant" an example of scientific method. For what if a student does determine the percentage of copper in this piece of brass? This is singular, and has no generality at all. Quantitative analysis is more time consuming, and somewhat more difficult than qualitative, but in general it depends upon less knowledge of scientific principles. The phrase "dry to constant weight" implies many hours of tedious work, of a sort which is not rewarding in terms of any appreciable increased scientific uuderstanding. What quantitative analysis does c~ntribute is actual experience i n the fundamentals of chemistry and in one of the most important components of almost all scientific work, namely accurate quantitative determinations. But although science depends upon accurate measurements, the scientific method is not accurate measurement. A house is not its foundations. One, but only one, of the components of the scientific method is accurate ohservat,ion, preferably quantitative. The essence of the scientific method (that is to say, t,he most characteristic, the most scientific thing about it) is the framing and testing of hypotheses. Experiments in quantitative analysis only participate in the essence of the scientific method in that very limited way in which almost anything does. "Determine the percentage of copper in this piece of brass" is scarcely more scientific than "count the number of beans in this bag." Where is science then? So far we have looked at, quite a lot of chemistry, or at least covered a fair amount of ground in terms of chemistry courses, without meeting more than a fleeting glimpse of the scientific method. I would like now to turn and approach this matter from a different direction, from the direction of mathematics. Mathematics is undoubtedly a science. It is also an exact science, although it is not an experimental science. In teaching mathematics, do me teach the scientific method? I think that most theoreticians of teaching would say that we do not. For the scientific method is usually thought of as the method of increasing the amount of scientific knonrledge. But we do not teach mathematics for the purpose of teaching the stu-
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dents the method of increasing mathematical knowledge: only for a few extreme specialists do we do that. We teach mathematics simply as knowledge and as science. Mathematical knowledge is increased, presumably, by scratching the head, tearing the hair, and worrying until a new idea comes. So is chemical knowledge, for that matter. And yet we cannot teach students to worry for an idea! One only learns that by actually doing it. Let us follow the mathematician, after he has passed the head-scratching stage, and see what he does. Once he has his idea, he takes large quantities of paper and scribbles all over it. He writes down symbols for the thoughts in his mind. What he deals with is not, strictly speaking, the symbols, they are only to help him (at a pinch, he could do his work without them), but the ideas that the symbols symbolize. What he does is to produce a train of thought, and this train of thought is characterized by certainty and by rigtdity, for at all points the conclusion follows necessarily from the premises, and only one conclusion follows. It is in view of this characteristic of mathematics that we call it a science. Now experimental sciences differ from mathematics in this respect, that, being experimental, they can never lead to complete certainty. There is always a minute probability of error. But experimental investigations may, or may not, approach mathematics in their use of logical trains of thought, of more or less rigidity. I suggest that this characteristic, in addition to generality, gives another criterion by which we may judge whether any particular aspect of chemistry is scientific or not. Does it involve a logical twin of thought? If it does, then it is already to that extent scientific. If it does not, then it fails, in this respect a t least, of being scientific in the fullest sense. Now let us look a t some operations in the chemical laboratory and see whether they are scientific or not. The determination of a melting point has some degree of generality (although not very much) and it is scientific on that score, but it involves no logical train of thought worth calling such. What if we make a long investigationfor determining the structure of a new organicchemical, say a new antibiotic? Here me must use a train of thought of considerable length. The investigation has some generality, and requires considerable logical thought. Suppose now that someone thinks of a new theory of organic chemistry, for example some new connection between structure and reactions. Such a theory is highly scientific,for it combines logical thought. with great generality. And so work in chemistry can be at any level, from highly scientific to work in which there is scarcely more than a trace of the much-advertised scientific method. To come back to the question, "What do students do in the laboratory?" I think it must be concluded that any laboratory course work contains precious little scientific method. (and this -eoes., of course. not onlv for chemistry but for any other experimental science as 8
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well). A brilliant research student may perhapa do a structure determination on an unknown compound, hut he will be the only one in the laboratory doing anything a t all scientific. The same student, later in his professional career, may perhaps develop such a thing as a new theory of resonance, or a new application of atomic structure theory to chemistry. When he does this, his work will he truly scientific, and in the fullest sense, but it may be noted that he will do this work not in the laboratory, hut while sitting at his desk, with reference books at hand. And so, what are we to do when we teach chemistry? We all agree that the scientific method is really more important than the facts, and I, a t least, conclude that, laboratory work doesn't help in the least in teaching it. And yet some idea of the scientific method has to he taught somehow. What are we to do about it? Let us go back, for a moment, t o the mathematician, whose science is easier because it is not an experimental science. The mathematics students are not, except for a few specialists, being taught the method of increasing mathematical knowledge. And yet they are scientists for all that. If they know any particular mathematical fact, they know also how to prove it. They can deduce the fact by a logical train from the starting point, which is a set of axioms or postulates. Our experimental science is different in that me are not allowed to postulate that results of experiments are this way, or thatway, we have to take whatever results the experiments give. Our theories are scientific in so far as they are general, and are deducible by trains of thought, not from postulates but from experiments. The experiments are a necessary condition for an experimental science, and for this reason we get students to do experiments, but experiments do not by themselves constitute a science. Reasoning is also required. I t should also be required of students. There should be required reasoning, as well as required reading. Facts must he known, particularly by the chemistry specialists, but the facts are only scientific if they are supported, via a train of reasoning, by experiments. This I suggest, is what we are to teach if we are really to teach the scientific method. We should teach the theory arrived at-we might consider, for example, the electronic theory of valence--and we should also teach the experiments on which the theory is based, and then make sure that the students really understand the logical connection between the two. Students should know why we believe in electrons, and why we believe in valence, and these "why's" are by no means so easy to answer as they appear. Students should be encouraged to fight back and try not to believe in our theories, for we only see the conclusive force of a train of argument by trying to deny it. If me can get students who are well stocked with chemical facts, and who can also give a cogent argument for believing in the existence of atoms, or for the theory of electronic resonance, then I think we could claim to have vroeressed a satisfactorv distance alone both horns. Then our science is no longer a Sacred Cow.
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