00:00:00.500 --> 00:01:59.000
Analogy Viewed from Science
If the causes are known that are efficacious in those other, similar phenomena, then this may give us clues concerning the causes in the phenomenon under consideration. Of course, whether this strategy works depends on the availability of closely analogous phenomena that are already explained (Herschel  1987, p. 148). Herschel (ibid., p. 149) wrote:
“If the analogy of two phenomena be very close and striking, while, at the same time, the cause of one is very obvious, it becomes scarcely possible to refuse to admit the action of an analogous cause in the other, though not so obvious in itself.”
Let us suppose we arrive at a parking lot, and a car is parked there. It is from a well-known American car maker, and you know the model, type, when it was made, etc. Then, you observe a second object, which you immediately recognize as a car as well. It is far far better build, with similar functionalities, but of unknown manufacturer. Now someone approaches you and asks: Hey, what do you think, was the second car made by another car manufacturer, or did some natural unguided processes build the car? We will obviously without thinking twice answer: What a foolish question. It is OBVIOUS that an unknown car maker made the Car. Biological Cells use instructional codes to make the building blocks of life and are full of molecular machines, which resemble machines made by humans through intelligent design with specific goals. We can, therefore, infer that, since like effects have most probably similar causes, that the agency which created biological Cells, and life, must be of intelligent nature.
1. Intelligent minds make factory plants full of machines with specific functions, set up for specific purposes. Each fabric can be full of robotic production lines where the product of one factory is handed over to the next for further processing until the end product is made. Each of the intermediate steps is essential. If any is mal or non-functioning, like energy supply, or supply of the raw materials, the factory as a whole ceases its production.
2. Biological cells are a factory complex of interlinked high-tech fabrics, fully automated and self-replicating, hosting up to over 2 billion molecular fabrics like Ribosomes & chemical production lines, full of proteins that act like robots, each with a specific task, function or goal, and completing each other, the whole system has the purpose to survive and perpetuate life. At least 560 proteins and a fully setup metabolome and genome is required, and they are interdependent. The probability, that such complex nano-factory plant could have emerged by unguided chemical reactions, no matter in what primordial environment, is beyond the chance of one to 10^150.000. The universe hosts about 10^80 atoms.
3. Biological Cells are of unparalleled gigantic complexity and adaptive design, vastly more complex and sophisticated than any man-made factory plant. Self-replicating cells are, therefore, with extremely high probability, the product of an intelligent designer.
David Hume Dialogues Concerning Natural Religion
Look round the world: contemplate the whole and every part of it: you will find it to be nothing but one great machine, subdivided into an infinite number of lesser machines, which again admit of subdivisions to a degree beyond what human senses and faculties can trace and explain. All these various machines, and even their most minute parts, are adjusted to each other with an accuracy which ravishes into admiration all men who have ever contemplated them. The curious adapting of means to ends, throughout all nature, resembles exactly, though it much exceeds, the productions of human contrivance; of human designs, thought, wisdom, and intelligence. Since, therefore, the effects resemble each other, we are led to infer, by all the rules of analogy, that the causes also resemble; and that the Author of Nature is somewhat similar to the mind of man, though possessed of much larger faculties, proportioned to the grandeur of the work which he has executed. By this argument a posteriori, and by this argument alone, do we prove at once the existence of a Deity, and his similarity to human mind and intelligence.
SCIENTIFIC MODEL S IN PHILOSOPHY OF SCIENCE, page 48
Nobody would doubt that analogy can play a considerable role in arguments, for developing or for illustrating points. This use of analogy can be found in different intellectual pursuits, such as literature, historiography, or philosophy, and there exist many examples in science —some of which are presented in section. However, analogies were not just used in science; some scientists from the nineteenth century on also discussed their use.John Herschel, mathematician, chemist, and astronomer, published a philosophical treatise in 1830 called A Preliminary Discourse on the Study of Natural Philosophy. In it, he highlights the role of analogy in science. Herschel ( 1987, p. 94) wrote that “parallels and analogies” can be traced between different branches of science, and doing so “terminate[s] in a perception of their dependence on some common phenomenon of a more general and elementary nature than that which form the subject of either separately.” In short, analogy enables us to link different branches of science, seeking something more general that joins them. Herschel’s example of the search for and finding of such a common nature is electromagnetism, demonstrated by Hans Oërsted (1777–1851), relying on similarities between electricity and magnetism. Another example Herschel mentions is the analogy between light and sound. He concludes that, when confronted with an unexplained phenomenon, we need to find and study similar phenomena.
The example Herschel gives for this kind of analogical inference is a stone being whirled around on a string on a circular orbit around the hand holding the string. Whoever is holding the string is able to feel the force pulling on the string due to the stone being kept on its circular orbit by the string. One may, therefore, according to Herschel, infer that a similar force must be exerted on the moon by the Earth to keep the moon on its orbit around the Earth, even if there is no string present in the case of the moon and the Earth. Herschel obviously views this strategy of drawing analogies as a legitimate path toward scientific knowledge when he concludes from this example: “It is thus that we are continually acquiring a knowledge of the existence of causes acting under circumstances of such concealment as effectually to prevent their direct discovery” (ibid., p. 149).
The aim is to find the mechanisms that constitute the hidden processes producing certain phenomena (ibid., p. 191). In the course of this search, different hypotheses may be formed about the mechanism and, in fact, different theorists may well form different hypotheses about a phenomenon (ibid., p. 194), perhaps based on different analogies employed. Herschel is adamant that, despite the dilemmas that might occur due to competing hypotheses, forming hypotheses is still highly beneficial for scientific exploration: “they [hypotheses with respect to theories] afford us motives for searching into analogies” (ibid., p. 196). In particular,
“it may happen (and it has happened in the case of the undulatory doctrine of light) that such a weight of analogy and probability may become accumulated on the side of a hypothesis, that we are compelled to admit one of two things; either that it is an actual statement of what really passes in nature, or that the reality, whatever it be, must run so close a parallel with it, as to admit of some mode of expression common to both, at least in so far as the phenomena actually known are concerned” (ibid., pp. 196–197).
Making such an inference is not only a theoretical undertaking, but it also has practical consequences. It leads to experiments: “[W]e may be thus led to the trial of many curious experiments, and to the imagining of many useful and important contrivances, which we should never otherwise have thought of, and which, at all events, if verified in practice, are real additions to our stock of knowledge and to the arts of life” (ibid., p. 197). In sum, analogies in science, according to Herschel, establish links between different areas of investigation. Moreover, they may aid explaining a new phenomenon on the basis of the causes acting in an analogous phenomenon already explained.
As such, analogies lead to the formulation of hypotheses (and the stronger the analogy, the more evidence for the hypothesis). Finally, they may guide the experimental testing of such hypotheses, thus promoting theory development.
I discussed Maxwell’s vortex model, his model of field lines, and mechanical understanding of physics in the last chapter. I now specifically consider his reflections on the use of analogy in science. One place where he explicitly considered the use of analogy in science is his “Address to the Mathematical and Physical Sections of the British Association” in Liverpool in 1870 (Maxwell  1890).³ He had in mind what we would today call a cognitive function of analogy. Maxwell’s emphasis is on the illustrations provided by analogies. The scientist should “try to understand the subject by means of well-chosen illustrations derived from subjects with which he is more familiar” (ibid., p. 219). The aim is “to enable the mind to grasp some conception or law in one branch of science, by placing before it a conception or a law in a different branch of science and directing the mind to lay hold of that mathematical form which is common to the corresponding ideas in the two sciences, leaving out of account for the present the difference between the physical nature of the real phenomena” (ibid., p. 219). An analogy is more than a teaching aid or dispensable illustration and can tell us what the system under study is like:
“the recognition of the formal analogy between the two systems of ideas leads to a knowledge of both, more profound than could be obtained by studying each system separately” (ibid., p. 219).
Maxwell voices reasons why analogies are useful in science. Using an analogy can be a strategy toward understanding an as yet not understood subject and hence contribute to generating knowledge by guiding the mind. Understanding, knowledge generation, and creativity are issues that have been investigated quite systematically in the cognitive sciences. Maxwell was also a great practitioner of the use of analogy in physics. Analogy was deliberately and systematically used in an effort to understand electrical effects that were not mechanical by nature. (Frequently these were analogies to mechanical models, see chapter 2, section 2.1, but not inevitably.) Maxwell not only devised the vortex model. An earlier and very instructive example is Maxwell’s model of electrical field lines that quite obviously exploits an analogy (Maxwell  1890). There, the field lines are represented by tubes in which an incompressible fluid moves, a model also broadly based on Thomson’s analogy between the flow of heat and the flow of electrical force. Maxwell’s aim in using this analogy is not to say what electrical field lines are physically like—they do not consist of a fluid—but how one might imagine them in accordance with the analogy guiding their theoretical description. Maxwell (ibid., pp. 157–158) wrote: “By the method which I adopt, I hope to render it evident . . . that the limit of my design is to show how, by strict application of the ideas and methods of Faraday, the connexion of the very different orders of phenomena which he has discovered may be clearly placed before the mathematical mind.”
Here Maxwell makes explicit how analogies, and analogies to classical mechanics, in particular, aid understanding. One beneficial point is that “the mathematical forms of the relations of the quantities are the same in both systems, though the physical nature of the quantities may be utterly different” (Maxwell  1890, p. 218).