"Only a Theory"

Back to Contents

    I normally donít use sneer quotes, but in this case their enclosed content well deserves them. At best the title of this essay expresses an unfortunate ignorance and at worst it represents a pure intellectual fraud. In either case it has no proper place in our culture. In this essay, then, I want to review what the word theory actually means. To that end I will review the Scientific Method.

    In popular speech the word theory has come to mean a guess, something not certain, something into which we do not want to invest a lot of faith. In that respect people have come to use it to denote the concept that scientists denote with the word hypothesis. In science hypothesis means a preliminary thesis, an educated guess, and the word theory refers to an hypothesis that scientists have tested and verified as true to the realm of discourse in which we apply it. We have a technique that we use to generate hypotheses and then to transform them into theories. We call that technique the Scientific Method.

    Also known as the empirical-inductive method, the Scientific Method that we learned in grammar school comes from "The New Atlantis", an unfinished science-fiction novel that Francis Bacon (1561 Jan 22 - 1626 Apr 09) wrote to sum up his own ideas on the proper way to conduct scientific research. Published in 1627, the year after Bacon died, "The New Atlantis" eventually inspired the creation of Englandís Royal Society, the original clearinghouse for scientific research.

    Bacon had his story narrated by an unnamed adventurer who, with his ship and crew, came to the unknown and mysterious island of Bensalem in the middle of the Pacific Ocean. In Bensalem the Englishmen see a land of wonders (at least by Seventeenth Century standards) and Baconís adventurer eventually comes to learn how the Bensalemites acquired their wonderful things. Messengers bring him and several of his men to the Father of Solomonís House, who tells them that "The end of our foundation is the knowledge of causes, and secret motions of things; and the enlarging of the bounds of human empire, to the effecting of all things possible." He then describes the officers of Solomonís House and their duties:

    1. First come the Merchants of Light, who go out into the world and "who bring us the books, and abstracts, and patterns of experiments of all other parts." In modern science these correspond to researchers, who search foreign libraries for descriptions of previous discoveries; naturalists, who search the world for new plants and animals; paleontologists, who search for new fossils; geologists, who search for new minerals; all providing the raw facts on which science operates.

    2. Next come the Depredators, who "collect the experiments which are in all books." We find the modern equivalent manifest as the graduate student who conducts a literature search in the library, looking for books and papers containing information on the topic their advisor has assigned to them.

    3. And with them come the Mystery-men, who "collect the experiments of all mechanical arts; and also of liberal sciences; and also of practices which are not brought into arts." Yes, the graduate studentís work just goes on and on.

    4. At the next stage the Pioneers or Miners "try new experiments, such as themselves think good." Modern scientists give this the fancy name of blue-sky research, but it really means just playing around in the laboratory to see what comes up.

    5. The Compilers "draw the experiments of the former four into titles and tables, to give the better light for the drawing of observations and axioms out of them." In modern terms, the organize the data provided by the others and then analyze those data for patterns that enhance our understanding of the phenomena whence the facts came.

    6. The Dowry-men or Benefactors "bend themselves, looking into the experiments of their fellows, and cast about how to draw out of them things of use and practise for manís life, and knowledge, as well for works

as for plain demonstration of causes, means of natural divinations, and the easy and clear discovery of the virtues and parts of bodies." We call these folks engineers, people who take scientific knowledge and invent new things, both of practical value to Humanity and of value in extending the explorations (natural divinations) of science.

    7. The Lamps, "after divers meetings and consults of our whole number, to consider of the former labours and collections,... take care, out of them, to direct new experiments, of a higher light, more penetrating into nature than the former." Think of theoreticians, who weave current knowledge into hypotheses and then dream up experiments or observations that will either verify or falsify those hypotheses.

    8. The Inoculators "execute the experiments so directed, and report them." The men and women who use Fermilabís Tevatron to explore the ultimate structure of matter as it relates to the physicistsí Standard Model come to mind here as an example.

    9. And lastly (but not leastly) we have the Interpreters of Nature, who "raise the former discoveries by experiments into greater observations, axioms, and aphorisms."

    Bacon clearly had fallen under the influence of William Gilbert (1544 May 24 - 1607 Nov 30). In 1600 Gilbert published his great work, De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure (On the Magnet, Magnetic Bodies, and on that Great Magnet the Earth), which became a sensation in Europe. Gilbert had taken upon himself the task of summing up all of Humanityís knowledge of magnetism so that others might use it as a foundation upon which to build more of such knowledge, as he himself had done. In the book Gilbert described using experiments to determine the nature of magnets and to show the Earth itself displays the effects that one would reasonably expect to emanate from a great magnet, thereby explaining why compass needles point north. He found that he could reject ancient theories of magnetism on experimental grounds. He cast his net wide and even included a description of the experimental work of the Thirteenth Century natural philosopher Peter of Maricount in the book.

    William Harvey (1578 Apr 01 - 1657 Jun 12) may also have influenced Bacon. From 1615 to 1656 Harvey held the position of Luleian lecturer for the Royal College of Physicians, a position that gave him the ability to work on a problem that he wanted to solve. In 1615 he began his work on a theory of blood and he began discussing his preliminary results in his lectures in 1616. He found no satisfaction in the then current theory of the blood, which theory held that blood is produced in the liver and then consumed by the body (at a rate of 540 pounds per day by Harveyís calculations). To gain satisfaction he conducted appropriate experiments and made observations whose data led him to infer that blood circulates within the body without undergoing the mass creation and destruction of the prevailing theory. And he discovered two circulatory loops Ė pulmonary (between the heart and the lungs) and systemic (between the heart and the rest of the body). In 1628 he published the result of his work in Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (An Anatomical Exercise on the Motion of the Heart and Blood in Animals).

    Both Gilbert and Harvey used carefully contrived experiments in their work, which may have given Bacon the key ingredient in his method. "This is the foundation of all," Bacon wrote, "for we are not to imagine or suppose, but to discover, what nature does or may be made to do." Over the nearly four centuries that have elapsed since "The New Atlantis" was published, natural philosophers and scientists have refined the method implicit in Baconís list. In 1687, for example, Isaac Newton added four "Rules for the Study of Natural Philosophy" in Book III of the Philosophiae Naturalis Principia Mathematica (The Mathematical Principles of Natural Philosophy), the famous work in which he laid out his theory of gravity:

    1. "No more causes of natural things should be admitted than are both true and sufficient to explain their phenomena." In essence this corresponds to Occamís Razor (entities are not to be multiplied beyond necessity). A famous example of this concerns Simon-Pierre de Laplace on the occasion of his giving Napoleon a copy of his treatise "Celestial Mechanics". Napoleon complained that the book contained no reference to God and Laplace replied, "I had no need of that hypothesis."

    2. "Therefore, the causes assigned to natural effects of the same kind must be, so far as possible, the same." This is just another way of stating Leibnitzís Principle of Sufficient Reason; "If something is so which could have been otherwise, then there must be a reason why it is so, and not otherwise." We would say that it takes a difference to make a difference, so if we donít see a difference in the effects ("natural effects of the same kind"), then we should not suppose a difference in their causes. Thus, for example, to the heat from a fire and to the warmth of a living body we assign the same cause, that of the chemical combination of organic matter with something in air (specifically, oxygen).

    3. "Those qualities of bodies that cannot be intended and remitted and that belong to all bodies on which experiments can be made should be taken as qualities of all bodies universally." Newton here refers to properties that we cannot increase or decrease. He had in mind in particular the inertial mass of bodies.

    4. "In experimental philosophy, propositions gathered from phenomena by induction should be considered either exactly or very nearly true notwithstanding any contrary hypotheses, until yet other phenomena make such propositions either more exact or liable to exceptions." In this statement Newton declares that induction can only give us contingent truth, not the necessary truth that the Greeks strove to find in, for example, plane geometry.

    Over time those rules and Baconís plan evolved into the six-step procedure that we now call the Scientific Method:

A. Observation

    We notice some phenomenon in the world and gather facts pertaining to it. In some cases we may take advantage of serendipity, the phenomenon of making a discovery through insight into an accidental finding of what we were not seeking. That description offers a fair idea of what Louis Pasteur meant when he claimed that chance favors the prepared mind. As a means of exemplifying the method I want to consider a phenomenon that inspired the Italian physician Francesco Redi (1626 Feb 18/19 - 1697 Mar 01) to conduct some rather famous experiments in 1668.

    <Our ancestors noticed (how could they not?) that wherever they put their garbage, the rotting garbage was soon writhing with maggots and engulfed in swarms of flies.>

B. Question

    We ask a question about the phenomenon, taking care to put it into such a form that we have the possibility of answering it by way of further observation.

    <Whence do the maggots and flies come?>

C. Hypothesis

    We contrive a tentative answer to the question, one that seems to provide an explanation of the phenomenon. We need multiple hypotheses wherever possible, to cover all conceivable answers to the question, and we must state them in a way that leaves them open to possible falsification through further observation, experiments, or deductive reasoning.

    <The flies might have come from some other place, but the maggots could not have done so. Further, maggots turn into flies, so the flies that we see may have originated as maggots in the garbage. Therefore, we take as our hypothesis the statement that the process of rotting creates maggots in the garbage by spontaneous generation.>

D. Prediction

    From the hypothesis we deduce a result that we expect to obtain from further observations.

    <If we put fresh garbage into a flask and let it rot, it will produce maggots and then flies.>

E. Testing the Hypothesis/Experiment

    We test the prediction through further observations of the phenomenon, even if we must contrive those observations through an experiment. In designing the experiment we must include controls to isolate the desired data from influences that would obscure their relation to our hypothesis.

    <In our workplace (laboratorium in Latin) we prepare two clean glass flasks and put a quantity of fresh meat into each of them. Then we put gauze or cheesecloth over the opening of one of the flasks and let the flasks sit together undisturbed. A day or two later we will see maggots and flies crawling over the putrefying meat in the open flask but no maggots or flies on the equally putrid meat in the flask closed off with cloth. Further, if we take a single maggot, put it into a flask with a piece of meat, and close off the flask with gauze, we will observe that the maggot changes form over time until it becomes a fly. Thus we obtain evidence to falsify the hypothesis that putrefying meat produces maggots and flies by spontaneous generation and to verify the hypothesis that flies bring to the rotting meat something that produces maggots, which become flies. Further experiments and observations will reveal that something to be eggs that the flies lay on the meat.>

F. Theory

    We take our well-tested and verified hypothesis or system of hypotheses to explain the facts that we have observed. Ideally a theory explains a phenomenon by relating it to other phenomena.

    <We conclude that rotting garbage does not generate maggots and flies, but rather that flies and only flies can beget more flies. If we carry out similar experiments with other animals and with plants, we can generalize that rule to Organism X and only Organism X can beget more Organism X, in which X represents any living thing. Thus we have a theory (a tested and verified hypothesis) that explains the phenomenon that we observed (maggots and flies appearing on putrid meat) and relates it to other phenomena (sexual reproduction in animals and plants).>

    Note that by obliging us to compare the predictions derived from our hypotheses with observations of the real world the Scientific Method compels us to correct hypotheses that do not correctly describe the phenomena that we have under study. In the Nineteenth Century, for example, biologists favored an hypothesis called pangenesis to explain heredity in plants and animals. By the end of the century they had accumulated enough evidence tending to falsify pangenesis that they began to replace it with Gregor Mendelís genetics as a model of heredity. Repeating Mendelís experiments with peas and extending them to other plants and animals (such as the fruit fly, Drosophila melanogaster), they verified the genetic hypothesis and incorporated it into our growing Theory of Life.

    So you see that using the phrase "only a theory" in any discussion of science is like using the phrase "merely the Constitution" in a discussion of American law. It reveals a great ignorance and misunderstanding of the subject and nothing more.


Appendix: An Example of Biblical Science

    You may have noticed that the Scientific Method does not include any procedure for devising hypotheses. It only gives us a procedure for testing hypotheses to see whether they give us descriptions that conform to Reality. We thus have complete freedom to make up hypotheses in any way that suits us. We can take inspiration from anything that seems relevant to the problem, from favorite science-fiction stories to the Bible. Indeed, up until the end of the Eighteenth Century natural philosophers (as scientists were called at the time) did draw inspiration from the Bible, precisely because at the time all natural philosophers were Creationists; that is, they believed that the Bible offers an accurate description of Reality.

    So why did scientists stop being Creationists? They started using the Scientific Method and discovered that hypotheses drawn from Biblical inspiration usually did not get verified when they were tested against Reality. In those instances in which the Bible did not turn out to be irrelevant, it turned out to be wrong. To see how that worked consider the problem of fossils.

A. Observation

    For millenia people have been finding bones of creatures that simply do not exist in this world. The Chinese called them dragon bones, the Greeks depicted some on their pottery as the bones of monsters, and the Native Americans conceived them in much the same way (recall that the eastern part of the State of Montana contains huge bone-beds). We call them fossils and we want to account for their existence.

B. Question

    How can we account for so many bones from creatures that no one has ever seen?

C. Hypothesis

    The bones came from creatures drowned in Noahís flood. The unfamiliar bones come from creatures that were not represented on the ark.

D. Prediction

    As the drowned animalsí bodies rotted their bones sank to the mud under the flood water and more mud came down to cover them. If the bones show any separation at all, we expect that they will be separated by density. We expect to find the less dense bones in rock layers above those containing the more dense bones because the denser bones would have sunk deeper into the mud.

E. Testing the Hypothesis

    Depending upon geologists to determine the order in which rock layers lie, paleontologists dig up fossils and organize the bones in vertical order in the rocks. They find that the bones are sorted by species, not by density. Thus, they find tyrannosaur bones in the rocks that lie higher than the rocks in which they find allosaur bones. They find the bones of triceratops in rocks that lie higher in the geological sequence than do the bones of stegosaurs. They find the bones of small dinosaurs mingled with the bones of big dinosaurs, but always the same species together.

    Further, the paleontologists also find the bones of marine animals, such as plesiosaurs and ichthyosaurs, that would not have been seriously inconvenienced by the flood. The flood hypothesis cannot explain the extinction of those creatures.

F. Theory

    In this case we must express our theory in a negative statement: the bones did not come from animals drowned in a world-spanning deluge. Our Bible-inspired hypothesis is false to Reality. The actual explanation for the bones comes from the Theory of Evolution, but thatís a different hypothesis that requires substantially more evidence than I can provide in this little essay.


Back to Contents