Like Kepler's discovery of the planetary laws, Michael Faraday's discovery of electromagnetic fields played a key role in a scientific revolution. Oddly enough, it was a revolution that countered an important feature of the Newtonian synthesis. Gravity was a force that acted in a straight line and was transmitted instantaneously over the space between bodies; this phenomenon was referred to as 'action at a distance'. Kepler would have been horrified by the idea; he thought in terms of a real force emanating from the sun, contacting the planets like light and sweeping them around their orbits.
Newton's gravity became one model for how forces might operate in other domains. By the late eighteenth century, it was clear that the attraction and repulsion of electrical charges followed an inverse square law. Perhaps electricity was another instance of action at a distance.
This viewpoint had its critics, among them Michael Faraday, who rejected both the primacy of matter and the notion that electricity operated 'at a distance'. The examples of Faraday's problem-solving processes described in this section are distilled from detailed, fine-grained cognitive studies by Tweney (Tweney, 1989a) and Gooding (Gooding, 1990a). "For him [Faraday], fields of force were the primary reality, and 'matter' a secondary or derived phenomenon. To understand his creative life, then, we must acknowledge his position as a revolutionary, as someone who demonstrates the practicality of a world view completely different from the prevailing one, and who does this, not by metaphysical argument, but by a series of compelling experimental demonstrations of such conceptual force that they could not be ignored" (Tweney, 1989a, pp. 94-5).
In 1816, Faraday saw electricity, magnetism and gravity as properties of matter; they accounted for cohesion and affinity, were responsible for attraction and repulsion and the same forces accounted for both chemical and physical phenomena (Tweney, 1985). Faraday's evolving mental model contained within it the possibility that the three forces could be unified (Nersessian, 1984).
Faraday was not an armchair speculator, however. His motto was, "il faut savoir de MANIPULER' (Tweney, 1985, p. 196). In 1820, Hans Christian Oersted showed that when a current passes through a wire, it acts as if it were a magnet. Furthermore, the force was directed transversely, at right angles to the wire--a major difference from gravitational force, which was directed radially. To understand what Oersted had discovered, Faraday repeated his experiments, varying conditions to explore the phenomenon. In the course of this research, he discovered that current through a wire could make a magnetic needle circle around it. In order confirm and demonstrate this discovery, Faraday invented the first electromagnetic motor.
David Gooding has reproduced this process in exquisite detail, replicating many of Faraday's experimental manipulations. Gooding believes that Faraday progressed via "a convergence of successive material arrangements (the apparatus) and successive construals (or tentative models) of the manipulation of the apparatus, and its outcomes" (Gooding, 1990b, p. 187). A construal corresponds roughly to what I am calling a mental model. Gooding's point is that, for Faraday, ideas, physical manipulations and objects are closely linked.
To find out how this linkage occurs, let us look more closely at what Faraday did. On September 3, 1821, Faraday began by exploring how magnetized needles behaved in the presence of strong currents. Humphry Davy, Faraday's mentor, and others predicted that a wire could be made to revolve or 'rotate'. To explore this possibility, Faraday built a new apparatus, consisting of a wire put through a cork which floated in water. The wire made contact with globules of Mercury at both ends; hence, he now had a wire that could rotate. He observed that the magnets thrust the wire form side to side: lateral motion, instead of rotation (Gooding, 1990a, p. 128). Then he bent the wire and discovered that repeated applications of the poles of the magnets produced a circular motion, if he looked down from above on the bent wire.
This account sounds simple and straightforward, as discoveries always do, after the fact. Gooding has shown how difficult it is to reproduce Faraday's result and how dependent it was on his construals (Gooding, 1990a).
At the end of the day, Faraday proposed building a new apparatus in which a magnet would be stuck upright in wax in a cup of mercury and a piece of wire allowed to circle around it when a current was applied. Faraday eventually produced a model of this experiment that could be shipped to other scientists so that they could replicate Faraday's results, given careful instructions on what to do.
Figure 2: Faraday's demonstration apparatus, which he sent to other scientists. All one had to do was add mercury and hook up a battery, and the wire would rotate. Reprinted with Permission of the Indiana University Press from Gorman (1992) Simulating Science , Fig 7-1, p. 143.
In effect, Faraday had created what W. Bernard Carlson and I call a 'mechanical representation'. We created this term because we noted that inventors seemed to have sets of familiar moves or operations that were embodied in specific components. For example, Edison took a drum cylinder from his phonograph and used it to rotate the film on the first motion picture camera (Carlson, 1990). According to Jenkins (Jenkins, 1984, p. 153), "Any creative technologists possesses a mental set of stock solutions from which he draws in addressing problems." This drum cylinder was part of Edison's repertoire of stock solutions: when faced with a new problem, he drew on them.
These familiar mechanical moves are representations because they can be run in the imagination as well as on the bench top. Not only can we manipulate the physical world, we can form mental representations based on our manipulations and run these representations in our imaginations. As Gooding says, "These mechanical representations can be retained in memory; moreover, they are so well understood that their use will be consistent and the implications of their properties for other components of a device can readily be worked out" (Gooding, 1990b).
For Faraday, the motor shown in Figure 2 served as a mechanical representation, even though his goal was understanding the phenomenon discovered by Oersted rather than inventing a new technological system. Any theoretical account of induction would have to incorporate the behavior of this device. Faraday shipped it to others to in order to persuade them to incorporate his mechanical representation into their thinking.
Latour (Latour, 1987) discusses the role of a strategy called 'black boxing' in the development of technoscience (he uses this term to refer to the fact that the boundary between science and technology is fuzzy at best). Once a device or an experiment or a finding is black-boxed, it is treated as an unquestionable fact: no one needs to look inside that particular black box again. Gooding does not discuss whether Faraday's demonstration motor became a black box for others, but mechanical representations can evolve into shared certainties, used by multiple inventors and scientists to embody knowledge and procedures.
In my analysis of Kepler's discovery processes, I remarked on the delicate balance between stubborn adherence to a hypothesis and willingness to abandon or alter it in the face of negative evidence. In an 1818 lecture, Faraday argued that 'mental inertia', by which he meant stubborn adherence to one's ideas, was both a blessing and a curse. A certain amount of such inertia saves one from discarding promising ideas prematurely, but an excess prevents one from recognizing when an idea or approach no longer works.
On August 29, 1831, Faraday found that a transient current was generated in one coil of wire wound around an iron ring when a battery was connected to, or disconnected from, a second coil wound around the same ring. This experiment did not appear 'out of the blue'. Faraday was engaged in a variety of experiments directed at transient effects. Faraday's electromagnetic experiments were part of a larger 'network of enterprises', a term coined by Howard Gruber (Gruber, 1981) to explain the way in which Darwin's diverse research interests connected, and also the motivations for his work. Darwin's work on topics like barnacles and pigeon breeding facilitated the development of his theory of evolution. Similarly, Faraday's efforts to take a variety of transient effects and make them visible were all part of his network of enterprises.
Faraday's first attempts to find electromagnetic induction can be seen in his notebook as early as 1822 where he outlined an experiment surprisingly similar to ones he would conduct in 1831. Why the delay? The answer, according to Tweney (Tweney, 1989b), is that in 1822 Faraday did not realize the magnetic induction effect could be transient. Whereas by 1831, he had developed heuristics for making transient effects visible. He had also read recently about new ways of obtaining powerful effects using large horseshoe-shaped electromagnets (Tweney, 1985). So on August 29th, 1831, when Faraday connected a coil to a battery and observed a brief deflection of the needle, this was more than a chance or 'serendipitous' discovery. He was returning to an old idea with a new mental model that highlighted the importance of transient effects and new heuristics for producing them.
In his 1831 experiments, Faraday followed the same pattern as in his 1821 experiments that led to the motor kit: he began with construals and exploratory experiments, then moved to hypotheses and demonstrations. He showed the same combination of stubbornness and flexibility that characterized Kepler. From August 29 to October 28, he attempted to use both electromagnets and permanent magnets to induce a current. Overall, he obtained positive results only 40% of the time. The bulk of the negative results came with the permanent magnet. At this point, he exhibited an appropriate mental inertia--he did not discard his hypothesis concerning magnetic induction in the face of a few negative results. Like any good experimenter, Faraday was aware of the possibility of noise or error in results, especially given that he was trying to obtain a transient effect.
On October 28, he switched to a more powerful electromagnet at a colleague's house and the proportion of positive results rose to 80%. Now he was beyond the exploratory phase and on to reliable demonstrations. Faraday gradually evolved a sophisticated mental model of the lines of force that were generated by a magnetic or an electrical current; these ideas culminated in his concept of fields of force, which were given mathematical expression by Maxwell (Nersessian, 1984).
With this brief coverage of Faraday, let us turn to the generalizations we have carried over from past cases.
1. Discovery depends on finding a problem significant enough to be labeled an important achievement.
Faraday certainly selected one of the most important 'cutting-edge' problems of his time: how magnetism could be used to induce electricity.
2. Discovery depends on transforming that problem into a form that suggests a promising path to solution.
James Clerk Maxwell referred to Faraday as a "mathematician of a very high order" (Gooding, 1994, p. 4), even though Faraday rarely used equations. But Faraday did use what he called a 'rough geometrical method', a kind of mental modeling. We saw an example of this above in his work on electromagnetic rotations that led to a prototype motor. The same kind of careful, rigorous mental modeling led gradually to his mature idea of fields, or lines of force. Gooding describes Faraday's method as follows:
(i) represent particular behaviours of magnets, illuminated lines of induction, diamagnets, crystals and light rays in terms of patterns; (ii) use changes in pattern or arrangement to guide the development of structural models of the interactions of forces; (iii) try these by running them in the imagination or by simulated and real experiments; (iv) explore limiting cases by real- and thought-experimentation that invokes practical knowledge of the geometry and topology of lines of force (Gooding, 1994, p. 22).
As Maxwell noted, Faraday provided "a method of building up an exact mental image of the thing we are reasoning about" (Gooding, 1994, p. 21). Kepler provided us with an example of a scientist who translated the results of his own mental modeling into equations. In Faraday's case, the equations were developed by James Clerk Maxwell, whose mathematical discovery played a critical role in the development of Einstein's theory of special relativity. An account of the interplay of visualization and formal mathematics in these discoveries lies beyond the scope of this book (Nersessian, 1984). It will suffice to say that Faraday 's lines of force did play an important role in one of Kuhn's great scientific revolutions: the shift from a Newtonian to an Einsteinian world view.
3. Discovery depends on finding or inventing good data.
Faraday's invention of the first electromagnetic motor suggests the way in which he created mechanical representations in order to discover.
4. Discovery depends on a combination of flexibility and stubbornness, depending both on the individual scientist's cognitive style and on how she or he represents the problem.
Faraday's lecture on mental inertia suggests the way in which he reflected on the problem of flexibility and stubbornness. Late in his career, Faraday began another investigation that indicates the way in which he was careful to maintain just the right balance. He still adhered to the idea that the three main forces were all manifestations of a single, underlying force. He had demonstrated the intimate relationship between electricity and magnetism. Now he sought to demonstrate gravitational induction. To accomplish this, he dropped electrical coils down through cylindrical 'shot towers' to see if movement through an electrical field would induce an electric current in the coil. Initially, results confirmed his expectations--a current was produced. But true to his own advice, Faraday looked carefully for evidence that could disconfirm his explanation. The shot towers, it turned out, contained small amounts of magnetic material; therefore, the effect was simply another example of magnetic induction. But Faraday never abandoned his gravitational hypothesis, because he also knew the effect he was looking for could be very weak--perhaps he needed a far longer tower with much more gravitational mass.
5. The act of writing is part of the discovery process.
Lavoisier and Krebs revised and re-organized ideas that became discoveries in the course of writing them up for publication. Faraday's similar space of re-organization and revision seems to have been his notebooks: "he left us records of about 30,000 experiments, both successful and unsuccessful, as well as a large number of speculative idea books, bibliographies, indexes, scrap-books, etc., etc." (Tweney, 1991, p. 301). Faraday's notebook served as:
1) An external memory aid. Here the goal was to faithfully record results and ideas in a form that facilitated retrieval. Faraday experimented with a number of such schemes. He began with a static alphabetical index, but it was hard to add appropriate categories as the material grows, so he adopted a scheme of John Locke's, in which each entry is indexed by its first letter and first vowel. He also experimented with numbering schemes. Faraday spent a great deal of time organizing his external memory.
2) A space for speculation and exploration. Faraday also kept idea books, that were not dated and were full of blank spaces, for use in recording additional ideas on the same theme. Sometimes entries were crossed out. Faraday also used loose slips that contained a brief description followed by numbers corresponding to a diary entry. Tweney speculated that Faraday was using these to create an equivalent of a modern database.
Is Faraday a hero, in the Campbellian sense? He was certainly treated as a hero by his contemporaries; as the Duke of Somerset wrote to Charles Babbage in 1835, "the story of Faraday is just one that is sure to make a great noise. There is something romantic and quite affecting in such a conjunction of poverty and passion for science...he comes out as the Hero of chemistry" (Schaffer, 1994, p. 41).
Like Kepler, Faraday had a religious faith that the universe was orderly and comprehensible. Faraday belonged to a group of Christians who referred to themselves as Sandemanians. But whereas Kepler believed in a mathematical harmony, Faraday believed the 'book of nature' was comprehensible to anyone who had the patience to read it slowly and carefully--higher mathematics were unnecessary:
Since the Sandemanians accept that the Bible is written in a plain style we would expect them to attribute similar characteristics to nature. Indeed, Faraday assumed that nature possesses an inner coherence and simplicity. For example, he accepted that nature was governed by a set of God-given causal laws. These laws were not merely the result of God speaking his will at the creation, they were also the work of a wise Creator who, avoiding unnecessary complexity, constructed the world on simple, plain principles. Faraday's belief in the indestructibility of force--all phenomenal forces being manifestations of a more basic conserved force--can likewise be interpreted as an instance of this more general principle of simplicity (Cantor, 1985, p. 73).
Faraday's struggle to read this book therefore does not seem like a struggle, only the result of patient, careful experimentation. Genius is supposed to come in sparks, leaps and insights--it is a product of imagination, not mere manipulation. But Faraday illustrates that scientific revolutions can come from intimate, experimental contact with Nature--genius is in the hands and their products as well as in propositions and equations.
One of the scientists in C. P. Snow"s novel The Masters (Snow, 1951) talks about how intoxicating it is to make Nature 'sit up and beg'. Faraday was such a scientist. However, in the case of a truly great experimenter, one might also argue that nature is making the scientist 'sit up and beg': the two are locked in an intimate dance. Faraday is a hero because he did not just read the book of nature--he wrote a part of it by slowly and carefully exploring the relationships between forces. This characteristic of Faraday's is captured by the computer program created to emulate his discovery processes.
Like Kepler and Krebs, Faraday has inspired computational research. In this case, instead of writing a program that emulates Kepler, (Gooding & Addis, 1990, Gooding & Addis, 1993) created a new computer tool called CLARITY which allows users to create diagrams that represent programs in a functional database called FAITH. CLARITY converts these diagrams into FAITH programs.
Instead of relying on computer scientists to model cases of discovery, CLARITY makes programming tools available to scholars like Gooding, who are studying science. As Gooding and Addis note, "CLARITY diagrams make hypotheses about inference and learning processes accessible; they can be discussed and criticized more readily than computer code and are therefore open to revision and experimentation in ways that most code-based modeling is not" (Gooding & Addis, 1993, p. 8).
For example, Gooding can use Clarity to generate graphs of Faraday's cognitive processes like the simple one shown in Figure 3. In this simple graph, we see Faraday begin with a goal, to make the wire move continuously, then decide to build an apparauts with which he will try to make the wire move. Triangles are used to dentoe goals, circles to represent mental outcomes and squares to represent physcial ones., including observations.
Figure 3: A problem behavior graph depicting the beginning of the experiments that led to Faraday's electromagnetic motor. Adapted from (Gooding, 1990, p. 180).
This simplified diagram does not do justice to the complexity of Gooding's scheme, which allows him to characterize hierarchies of goals by the way he shades the arrows and show embodied cognition by superimposing circles and squares. Gooding was able to graph whole sequences of Faraday's experiments in this manner (Gooding, 1990).
CLARITY could allow other scholars to do the same, and also permit them to see the assumptions underlying the graph. One could even draw CLARITY diagrams while interviewing a scientist, and run them to see if the results corresponded to elements of the actual discovery process. Such graphs would facilitate for more rigorous comparison of the cognitive processes of different discoverers.
CLARITY can be viewed as a compromise between top-down, algorithmic models like BACON and KEKADA that specify processes in terms of rules and bottom-up approaches typified by connectionist systems that learn from examples (Waltz, 1988). The functional approach allows one to create top-down models of discovery processes, but also to build them from the bottom up, looking closely at the fine-grained activities of the scientist.
An intelligent reader might ask at this point, "Who cares about all these computational simulations?" The central problem of cognitive science is that it is impossible to directly observe the mind in action. Therefore, one approach is to build a model of the mind, run it, and see if, given the same inputs as a discoverer, it produces the same outputs. Indeed, most cognitive scientists have accepted that any theory of human mental functioning should be expressed as a computer program of some sort (see Gorman, 1992 for a counter-argument). The danger is that more time will be spend building discovery programs than studying discoverers and further, that the languages and concepts of those doing the studying will be very different from those doing the modeling. CLARITY shows promise of being a computer tool that will encourage collaboration between modelers and scholars who do not have a computational background. So far, CLARITY has been tested only on Faraday, who was already the object of extensive study. To prove its promise, CLARITY needs to be tried on other cases.
In particular, the program's creators recognize that they need to come up with a "multi-agent model of the interactions of individuals and groups of practitioners, particularly the dynamics of consensus-seeking and of controversy in science" (Gooding & Addis, 1993, p. 99). In other words, Gooding and Addis recognize that discovery is a social process. Hitherto, we have talked mostly about the mind of the individual discoverer. Before we turn to a closer look at the literature on the psychology of discovery, let us cover at least one case that clearly illustrates how discovery involves multiple 'agents'.
This page was last edited: Wednesday, July 14, 1999