Tag Archive: Popper

Against the autonomy of World 3

Popper (1972, 107-108) presents one of his “standard arguments for the independent existence of the third world” with the help of a thought experiment. Compare the following two situations: (a) All our machines and tools are destroyed, and all our knowledge of them. But books and our capacity to learn from them survive; and (b) all our machines and tools are destroyed, and all our knowledge of them. All books are destroyed, too.

In the second case, Popper argues, it would take much more time for the world to reemerge. I think that this hypothesis is quite plausible. Let us assume it is true. What follows from this? According to Popper (1972, 108), his thought ex­periment demonstrates the “reality, significance, and degree of autonomy of the third world.”

This, however, does not follow from the premises of the thought experiment. Strictly speaking, this thought experiment only demonstrates the significance of books. We may conclude that books, at least some of them, are significant things, which could, under special conditions, decisively influence how the world goes on. If we presuppose, in addition, that books are world 3 objects, then it follows that some world 3 objects are significant things. But the thought experiment itself does not tell us that there is a world 3, and that books are world 3 objects. Books could have great impact yet be physical things. After all, physical things can also significantly change the world, and our life (e.g., the impact of a meteorite).

Popper further illustrates the reality and influence of world 3 by referring to problem situations in science and mathe­matics. As an example, he presents Brouwer’s invention of his theory of the continuum. He cites the following statement by Heyting about Brouwer’s invention: “If recursive functions had been invented before, Brouwer would perhaps not have formed the notion of a choice sequence” (Popper 1972, 109).

The details of this example do not matter. The example illustrates the point in question. Quite plausibly, problem situa­tions may greatly influence the thinking of scientists. But here, too, we have to distinguish between two questions. The first is whether problem situations exert an influence on world 2, and perhaps on world 1. It is quite another question what problem situations are ontologically. They might be world 3 objects, but they might also belong to worlds 1 or 2. Popper’s example teaches us nothing about this question. It only illustrates the impact of problem situations, not their ontological character. [291]

Intellectual honesty

Intellectual honesty does not consist in trying to entrench, or establish one’s position by proving (or ‘probabilifying’) it — intellectual honesty consists rather in specifying precisely the conditions under which one is willing to give up one’s position. [92]

The stimulus to further development

As Max Planck once remarked in a lecture,

A living and flourishing theory does not avoid its anomalies but searches them out, for the stimulus to fur­ther development comes from contradiction, not from confirmations.

The point to keep in mind is that although falsifiability, rather than verifiability, is the most important criterion in determin­ing whether a theory is scientifically meaningful, its usefulness for the greater task of building confidence in a theory is limited. A theory is accepted not simply because it has withstood many attempts at falsification, the need for such tests notwithstanding, but because it leads to predictions that are experimentally verified. After all, the purpose of a theory is to be productive and not just to fail to be wrong. [115]

Kuhn on falsification

A very different approach to this whole network of problems has been developed by Karl R. Popper who denies the existence of any verification procedures at all. Instead, he emphasizes the importance of falsification, i.e., of the test that, because its outcome is negative, necessitates the rejection of an established theory. Clearly, the role thus attri­buted to falsification is much like the one this essay assigns to anomalous experiences, i.e., to experiences that, by evoking crisis, prepare the way for a new theory. Nevertheless, anomalous experiences may not be identified with falsifying ones. Indeed, I doubt that the latter exist. As has repeatedly been emphasized before, no theory ever solves all the puzzles with which it is confronted at a given time; nor are the solutions already achieved often perfect. On the contrary, it is just the incompleteness and imperfection of the existing data-theory fit that, at any time, define many of the puzzles that characterize normal science. If any and every failure to fit were ground for theory rejection, all theories ought to be rejected at all times. On the other hand, if only severe failures to fit justifies theory rejection, then the Popperians will require some criterion of “improbability” or of “degree of falsification.” In developing one they will almost certainly encounter the same network of difficulties that has haunted the advocates of the various probabilistic verifi­cation theories.

Many of the preceding difficulties [Kuhn is referring to inductive reasoning] can be avoided by recognising that both of these prevalent and opposed views about the underlying logic of scientific enquiry have tried to compress two largely separate processes into one. Popper’s anomalous experience is important to science because it invokes competitors for an existing paradigm. But falsification, though it surely occurs, does not happen with, or simply because of, the emergence of an anomaly or falsifying instance. Instead, it is a subsequent and separate process that might equally well be called verification since it consists in the triumph of a new paradigm over the old one. [146-7]

Gould’s view of Popperian falsification

Philosopher Karl Popper has argued for decades that the primary criterion of science is the falsifiability of its theories. We can never prove absolutely, but we can falsify. A set of ideas that cannot, in principle, be falsified is not science.

The entire creationist argument involves little more than a rhetorical attempt to falsify evolution by presenting supposed contradictions among its supporters. Their brand of creationism, they claim, is “scientific” because it follows the Popperian model in trying to demolish evolution. Yet Popper’s argument must apply in both directions. One does not become a scientist by the simple act of trying to falsify another scientific system; one has to present an alternative system that also meets Popper’s criterion—it too must be falsifiable in principle. [256]

Proposals for the scientific method

When verificationism failed, philosophers proposed that science progresses because scientists follow a method guar­anteed to lead to the truth. Proposals for the scientific method were offered by philosophers such as Rudolf Carnap and Paul Oppenheim. Karl Popper put forward his own proposal, which was that science progresses when scientists pro­pose thories that are falsifiable—that is, they make statements that can be contradicted by experiment. According to Popper, a theory is never proved right, but if it survives many attempts to prove it wrong, we can begin to have faith in it—at least until it is finally falsified. [296]

The meagre foundation of science

[E]ver since the seminal work of philosopher of science Karl Popper, for a scientific theory to be worthy of its name, it has to be falsifiable by experiments or observations. This requirement has become the foundation of the “scientific method.” [262]

Popper as a pale reflection of Mill

An account and a truly humanitarian defence of this position [“The separation between the history of a science, its philo­sophy and the science itself dissolves into thin air and so does the separation between science and non-science”] can be found in J.S. Mill’s On Liberty. Popper’s philosophy, which some people would like to lay on us as the one and only hu­manitarian rationalism in existence today, is but a pale reflection of Mill. It is specialized, formalistic and elitist, and devoid of the concern for individual happiness that is such a characteristic feature of Mill. We can understand its peculi­arities when we consider (a) the background oflogical positivism, which plays an important role in the Logic of Scientific Dis­covery, (b) the unrelenting puritanism of its author (and of most of his followers), and when we remember the in­fluence of Harriet Taylor on Mill’s life and on his philosophy. There is no Harriet Taylor in Popper’s life. [34]

Vorläufer des Falsifikationsprinzips

Das Falsifikationsprinzip wurde erstmals von Karl Popper ausgesprochen. Erstmals? Alle philosophischen Ideen ha­ben Vorläufer. In unserem Falle ist der Oxforder Gelehrte Robert Grosseteste (etwa 1168-1253) ein besonders interes­santes Beispiel. Nach Losee war er der erste mittelalterliche Denker, der die logischen und methodologischen Pro­bleme von Induktion, Verifikation und Falsifikation systematisch untersuchte. (Bei Popper wird er, soweit ich sehe, nir­gends erwähnt. Aber Kopernikus erwähnt seinen wichtigsten Vorgänger, Aristarch, ja auch nicht.) Grosseteste benutzte und empfahl die Methode der Falsifikation, um mit Hilfe des modus tollens von einer Gruppe konkurrierender Hypo­thesen alle bis auf eine zu eliminieren. Die wesentliche Asymmetrie zwischen Verifizierbarkeit und Falsifizierbarkeit scheint er jedoch nicht er­kannt zu haben. [117]

Science is a way of thinking

Science is a way of thinking much more than it is a body of knowledge. Its goal is to find out how the world works, to seek what regularities there may be, to penetrate the connections of things—from subnuclear particles, which may be the constituents of all matter, to living organisms, the human social community, and thence to the cosmos as a whole. Our intuition is by no means an infallible guide. Our perceptions may be distorted by training and prejudice or merely because of the limitations of our sense organs, which, of course, perceive directly but a small fraction of the phenomena of the world. Even so straightforward a question as whether in the absence of friction a pound of lead falls faster than a gram of fluff was answered incorrectly by Aristotle and almost everyone else before the time of Galileo. Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage—at the very least the courage to question the conventional wisdom.

Beyond this the main trick of science is to really think of something: the shape of clouds and their occasional sharp bottom edges at the same altitude everywhere in the sky; the formation of the dewdrop on a leaf; the origin of a name or a word—Shakespeare, say, or “philanthropic”; the reason for human social customs—the incest taboo, for example; how it is that a lens in sunlight can make paper burn; how a “walking stick” got to look so much like a twig; why the Moon seems to follow us as we walk; what prevents us from digging a hole down to the center of the Earth; what the definition is of “down” on a spherical Earth; how it is possible for the body to convert yesterday’s lunch into today’s muscle and sinew; or how far is up—does the universe go on forever, or if it does not, is there any meaning to the question of what lies on the other side? Some of these questions are pretty easy. Others, especially the last, are mys­teries to which no one even today knows the answer. They are natural questions to ask. Every culture has posed such questions in one way or another. Almost always the proposed answers are in the nature of “Just So Stories,” attempted explanations divorced from experiment, or even from careful comparative observations.

But the scientific cast of mind examines the world critically as if many alternative worlds might exist, as if other things might be here which are not. Then we are forced to ask why what we see is present and not something else. Why are the Sun and the Moon and the planets spheres? Why not pyramids, or cubes, or dodecahedra? Why not irregular, jumbly shapes? Why so symmetrical worlds? If you spend any time spinning hypotheses, checking to see whether they make sense, whether they conform to what else we know, thinking of tests you can pose to substantiate or deflate your hypotheses, you will find yourself doing science. And as you come to practice this habit of thought more and more you will get better and better at it. To penetrate into the heart of the thing—even a little thing, a blade of grass, as Walt Whitman said—is to experience a kind of exhilaration that, it may be, only human beings of all the beings on this planet can feel. We are an intelligent species and the use of our intelligence quite properly gives us pleasure. In this respect the brain is like a muscle. When we think well, we feel good. Understanding is a kind of ecstasy. [15]

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