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Thursday, May 20, 2010

A Philosophical Case for the Serendipity of Science

Chapter 3B

A Philosophical Case for the Serendipity of Science

My argument has two parts. The first part establishes a strong connection between scientific change and serendipity. The second part establishes a strong connection between scientific exploration and scientific change.

The first part goes as follows.

1. Scientific views are instruments for interacting with the universe, and they tell us what the universe is like.

This statement may sound plausible, but it is by no means universally accepted. According to a still popular view, scientific knowledge is objective, objective is equated with factual, and as a result facts become the business of science. From this it presumably follows that the function of science is to collect facts about the universe, and that the function of space science is to collect them from space.

This conventional, and relatively static, picture of science makes it difficult to defend space science. If radiation from a certain region of the cosmos has been coming toward us for millions of years, and will be coming for millions more, what is the hurry to put a telescope in orbit to observe it right now?

The answer lies in a different notion of science: a notion that was first brilliantly developed by Galileo in 1632 and finally recovered by Paul Feyerabend and Thomas Kuhn in the 20th century. It is the notion that scientific views or theories are like spectacles through which we experience the universe.[1] And as Kuhn taught us, they are also instruments we use to interact with the universe.

To illustrate how far the shift on emphasis away from the collection of facts can take us, consider briefly the manner in which Galileo surmounted one of the main obstacles to Copernicus' idea of the motion of the Earth.

In his analysis of the history of science, Paul Feyerabend explains how the Aristotelians employed the Tower Argument to show that the "facts" refuted the Copernican view. Suppose, with Copernicus, that the Earth moves. If you then drop a stone from the top of a tall tower, by the time the stone hits the ground the tower will have moved with the Earth, and thus the point of impact will be a considerable distance from the base of the tower. For the impact to be as close to the base of the tower as it actually is, the stone should follow a parabolic motion. But it obviously falls straight down (Figure 3.1). Thus the supposition that the Earth moves cannot be correct.

We now know, however, that Copernicus was right: the Earth moves. But why should his view fly in the face of such obvious facts as the vertical, downward motion of the stone? As we see the stone leave the tower, we find it natural to say that the stone moves straight down. But this "natural interpretation" assumes that a normal observer under normal conditions can determine the motion of the stone. "Real" motion is presumably observable motion: a change in location that we can measure (in this case a normal observer functions as the measuring instrument: the motion of the stone is what he sees the stone do). In terms fashionable today, the Aristotelian opponents of Copernicus and Galileo assumed that motion was operational (determinable by measurement) and absolute.

Galileo's ploy, according to Feyerabend, was to offer a different set of "natural interpretations" according to which we do not actually observe the real motion of the stone. There are, Galileo explained, two components to the motion of the stone: a straight motion toward the center of the Earth and a circular motion that it shares with the earth (circular inertia). The stone, the tower, and the observer all share this circular inertia. But shared motion cannot be observed (when flying in a jetliner, we do not "see" the passenger in the next seat as cruising at 600 miles per hour, even though we may know that he is). Thus we can perceive neither circular inertia nor the real (compound) motion of the stone. The normal observer sees only that component of the motion of the stone that he does not share: the motion toward the center of the Earth. Therefore, concludes Galileo, the stone does not fall straight down – it only seems to.

In this manner Galileo defused one of the main objections to the Copernican view: the crucial "facts" his opponents adduced make theoretical assumptions. Certainly, Galileo points out, if we already believe that the Earth does not move, we must conclude that the motion of the stone is “straight and perpendicular.”[ii] But if we believe instead that the Earth rotates, we must conclude that the “motion would be the compound of two motions,” as well as parabolic (a “slanting movement,” Figure 3.2). What the “facts” are depends on what scientific theory we accept. Clearly, Galileo says, Aristotle, Ptolemy, and their followers “take as known that which is intended to be proved.”

Galileo’s opponents, once again, had an operational concept of motion: motion is observable change of position over time. Galileo proposed instead a concept of compound motion in which one of the components is theoretical (and in principle unobservable, since the observer shares it).[iii] He thus defused the objection, not by advancing a set of facts free of theoretical assumptions, but a set of facts with different assumptions. The new real motions of objects were no longer directly observable, and the relativistic basis for holding this view introduced a new way of doing physics.

Different views of the universe thus lead to different assumptions, and different assumptions lead to different evaluations of what is to count as evidence, as facts. They also lead, as in the case of the Copernican revolution, to a profound transformation of our understanding of what the world is like.

In the 19th Century, William Prout suggested that all elements are formed from hydrogen. He thus predicted that all atomic weights should be multiples of 1, since that is the atomic weight of hydrogen. But careful measurements of the atomic weights of several pure elements, chlorine for example, did not produce whole numbers. As in the case of the Tower Argument and similar experiments[iv], the seemingly impregnable facts refuted an interesting new view.

A century later, though, a new atomic theory explained that each element differs from others by the number of protons in the atomic nucleus (exactly matched by the number of electrons “around” it). The new theory, however, also proposed particles called “neutrons” in addition to protons and electrons. Neutrons, which have mass but no charge, are also located in the nucleus, but their number can vary. That is, there can be several varieties of the same element (isotopes), with different atomic weights.[v] The extremely careful 19th Century measurements of the atomic weight of pure chlorine turned out to be measurements of the mix of chlorine isotopes found in nature. The atomic weight of each of the isotopes is indeed a whole number, much in accordance with Prout’s insight. A revolutionary theory, once more, changed in this case not only the “facts” but also our understanding of what an element is.[vi]

According to Kuhn, scientific views (which he called "paradigms") tell us what elements there are in the world and what relations exist between these elements. Suppose, for example, that scientists come to view the basic components of the world as little “billiard” balls in frequent collisions. As soon as we begin to view the world in this manner, a host of new problems requires solutions. If a collision is perfectly elastic, what happens to the particles? (The system’s momentum going in must equal its momentum going out.) What happens in inelastic collisions? (Some energy will be dissipated, probably as heat.) Reasonably precise solutions to such problems are found using the laws and mathematics of a new science (e.g., Newton’s), which are tailored to the kinds of problems that arise because we think the world is made of little billiard balls.

How we view the world thus determines what sorts of problems are meaningful and what kinds of solutions are acceptable. This is, of course, a rough and preliminary way of describing science, but it suggests the sense in which we can speak of science as a pair of spectacles that permits us to see the world. I am speaking metaphorically, to be sure. But that metaphor is by no means farfetched. We should realize that without our scientific views we would simply be blind to many aspects of the universe.

Sight itself is more than a mechanism for forming mental images of the world: it is also a complex means of interaction with the world. Consider two examples. As you walk down a familiar street at night you vaguely make out in front of you some amorphous shapes. Suddenly you hear the nasty growl of an attack dog, and almost instantly one of the amorphous shapes turns into the well defined, and frightening, body of a Doberman. The threat we hear informs and changes what we see.

In a famous experiment, F.P. Kilpatrick invited subjects to look at two rooms through peepholes.[vii] They first looked at a normal (rectilinear) room. The next room was distorted in that the left wall was twice as long as the right, but the subjects noticed nothing unusual about it. They were then asked to touch a mark on the back wall with a long stick. Since they saw the room as normal, they also saw the back wall as parallel to the front one, and so their attempts to touch the mark did not succeed. Experimenting with the stick led them eventually to success, and as soon as they achieved it, they immediately saw the room as distorted.

These two cases illustrate how the visual cortex circuits that let us see the “properties” of objects (what people understand by visual perception) are meant for flexible interaction with our environment. Another, faster circuit allows us to react almost instantly without even making “pictures” of the object. A professional tennis player, for instance, will react to the flight of the ball even before consciously seeing the ball[viii]. And animals that live in completely different environments emphasize completely different senses and the brain structures that support them. Bats use sonar, and some fish electric fields. In general, animals perceive as they do because their senses were of practical advantage to their ancestors as they interacted with the world.

Scientific views also give us more than pictures or representations of the universe. Like magnified senses, they provide means of interacting with the universe, for they ask questions by seeing, probing, and touching nature at many different energies and magnitudes. Thus when we learn to "see" the universe we actually learn to make contact and deal with its diverse facets in many different ways.[ix]

This interactive view of science is controversial amongst philosophers, and it may sound strange to scientists who believe that the facts always decide the worth of scientific ideas, never the other way around. But it receives strong support from the history and the practice of science (especially at crucial scientific junctures, such as Galileo’s defusing of the Tower Argument, where the facts we choose depend on the theories we favor), as I have argued elsewhere.[x] The point of this excursion into a central controversy in the philosophy of science is that scientific exploration in general, and space exploration in particular, creates circumstances that force science into such crucial junctures. Exploration thus, as we will see below, makes inevitable the radical transformation of the ways we “see” and interact with the universe.

I place quotation marks around see to prevent a pointless but surprisingly common misinterpretation of the approach under discussion. Some philosophers take this interactionism to imply that with changes of worldview come changes in the actual visual perception of the world. Sometimes this may happen: expectation does affect perception and different theories may set up different expectations. But it need not happen in the cases when we are trying to decide between two theories. Galileo saw the stone fall straight down, just as the Aristotelians did. And Prout and his critics all saw the same numbers on their instruments. Same perceptions but different facts. Galileo’s argument destroyed not only the empiricist distinction between theory and fact, but also the empiricist connection between perception and fact.

Nevertheless, this is not a book about the limitations of empiricist theories of science. My intent is rather to apply and illustrate the findings of the interactionist approach to the nature of science. I trust that those applications and illustrations will best show the worth of such findings.[xi] In any event, with those findings in mind, our problem of justifying space exploration will take on an entirely new light as we place emphasis on the essential transformations of science and their consequences.

[1]. The most important references in this regard are: Paul K. Feyerabend, Against Method, NLB (1975); Thomas S. Kuhn, The Structure of Scientific Revolutions, University of Chicago Press (2nd. Edition, 1970); Imre Lakatos, The Methodology of Scientific Research Programmes, Cambridge University Press (1978); Karl R. Popper, The Logic of Scientific Discovery, Hutchinson (1959).

[ii] This and the following quotations from Galileo come from his Dialogue Concerning the Two Chief World Systems, Modern Library of Science, edition of 2001.p. 162. The original was published in 1632. On p. 198, Galileo restates the argument. One ought to say, he claims, that

If the earth is fixed, the rock leaves from rest and descends vertically; but if the earth moves, the stone, being likewise moved with equal velocity, leaves not from rest but from a state of motion equal to that of the earth. With this it mixes its supervening downward motion, and compounds out of them a slanting movement.

[iii] From a spaceship today we could see the parabolic motions of falling objects, but this option was neither practically nor rhetorically available to Galileo. And, at any rate, as long as the observer shares the rotation of the Earth, the real motion of the falling rocks would remain in principle unobservable to him.

[iv] Galileo proposed many experiments, some with cannon balls, to arrive at the same conclusion of the Tower Argument: that the Earth could not move. That is, he made the opponents’ position even stronger than his actual opponents had, and then demonstrated that such a position was question begging. “Second Day,” op. cit.

[v] Prout proposed his idea in 1815. By the early 1900s, Hantaro Nagaoka had proposed a “Saturn” model of the atom and Lord Kelvin and J.J. Thompson had defended the “plum-pudding” model. It was not until 1911, though, that Ernest Rutherford’s idea of an atomic nucleus that contained both protons and electrons could perhaps begin to support Prout’s hypothesis. The discovery of the neutron, the full understanding of isotopes, and the full retrospective vindication of Prout would have to wait until James Chadwick’s experimental results in 1932. A very readable account appears in D. Lincoln’s Understanding the Universe: From Quarks to the Cosmos, World Scientific Publishing Co., 2004.

[vi] Lakatos offers a particularly interesting philosophical account of this and similar incidents. Op. cit.

[vii] Kilpatrick used three rooms, but I am describing only part of the experiment. Explorations in Transactional Psychology, New York University Press, 1961.

[viii] S. Blackmore, Consciousness, Oxford University Press, 2004, pp. 38-39.

[ix] For a more detailed account see my Evolution and the Naked Truth, Ashgate, 1998. For a converging view from the psychology of perception see Victor S. Johnston’s Why We Feel: The Science of Human Emotions, Perseus Books, 1999.

[x] In addition to the works mentioned in the notes above, including of course Galileo’s, I would suggest reading two of my papers that summarize many of the main arguments: “A RĂ©habilitation of Paul Feyerabend,” which can be found in The Worst Enemy of Science? Essays in Memory of Paul Feyerabend, which I edited with John Preston and David Lamb for Oxford University Press, 2000, pp. 58-79, and “Conquering Feyerabend’s Conquest of Abundance,” Philosophy of Science, 69 (September 2002) pp. 519-535.

[xi] This situation mirrors the process by which Galileo’s view, the Copernican theory, came to be accepted. Such a process is best explained within an evolutionary and neurobiological perspective of the nature of science. For an account of that perspective see Evolution and the Naked Truth, op. cit.

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