Philosophy 101 Day 10

1. Philosophy 101 Day 10 Copyright 2006 Makoto Suzuki

2. Aims • Introduce the Demarcation Problem and explain its practical significance. • Consider several proposals. • If time allows, consider how the Darwinian Evolution theory and Creationism fare.

3. The Demarcation Problem • Kitcher’s “Believing Where We Cannot Prove” concerns the question of whether the Darwinian theory of evolution – as well as Creationism – is a science or a pseudoscience. • To answer this question, one needs to has an answer to a theoretical question: “what, if any, distinguishes science from pseudoscience?” • Note: though both Kitcher and Creationists agree that there is such a distinction, it is possible – though perhaps not plausible – to deny its existence. • This problem is called “the demarcation problem.” • We will consider several criteria invoked by Creationists and Kitcher to this question.

4. The Significance of The Problem • The demarcation problem is not merely intellectually stimulating but also practically important. • This is because the question “what, if any, distinguishes science from pseudoscience?” has a bearing on: • whether to believe what creationism/intelligent design view, astrology, parapsychology, alternative medicines (acupuncture, homeopathy, Ayurveda, yoga, chiropractic, massage, aromatherapy, kirurian picture, humor therapy, dance therapy and so forth) etc. say and rely on it in life; • the policies concerning education (Kitzmiller v. Dover Area School District (2005)), research funding, treatment permission (Access to Medical Treatment Act), license system, insurance and so on.

5. Proposed Criteria of Science • The Existence of Conclusive Proof (30-35) • Falsifiability (35-44) • Kitcher’s Three Criteria (45f) • Independent Testability of Auxiliary Hypotheses • Unification • Fecundity

6. Other Conditions? • One candidate is the consistency and coherence with other successful theories. • Take Creationism and Darwinian evolution theory for example. Creationists have trouble here. • Geology (the earth is about 4.6 billion years old) vs. many Creationists’ view that the earth was made about 6,000 years ago • Plate tectonics vs. many Creationist’s explanation of world topography by catastrophism (involving Noah’s flood) • Hydromechanics vs. many Creationist’s explanation of the accumulation of strata and fossils by Noah’s flood • However, note that some creationists and intelligent design theorists disown these problematic views. • Darwinism does not conflict with other successful theories.

7. 1. The Existence of Conclusive Proof as the Criterion of Science (30-35) • Is any scientific theory conclusively proved or confirmed? • The answer is negative for two reasons. • Reliance on Inductive Arguments: Science provides generalizations, and the contents of these generalizations of laws are way beyond our data (i.e., observation reports). • Our observation reports can be mistaken. Our senses are fallible. Further, observations are often theory-laden, so they turn out to be false if the theories they depend on turn out to be false. (E.g., Kitcher’s examples (on p.34) of observations through electron microscopes and cloud chambers.)

8. 2. Falsifiability as the Criterion of Science: the Basic Idea • The basic idea is that scientific theories can be tested by observations while non-scientific theories cannot. • For example, it seems that a theory that expresses Kepler’s first law (“The orbit of a planet about the sun is an ellipse with the sun at one focus”) seems to be scientific because apparently it has a certain empirical content and thus can be tested. • However, for example, a guru’s theory that quietness is wholeness in the center of stillness seems to be non-scientific because it has no empirical content and thus cannot be tested. • The view that falsifiability is the criterion of science is a sophistication of this basic idea.

9. 2.Falsifiability • Popper holds that for a theory to be scientific, it must be empirically falsifiable. • A theory is empirically falsifiable if it has observable consequences. • A theory is taken as a set of generalizations about the features of recondite things (genes, atoms, gravitational forces, quasars, and so on). • The consequences of a theory are the conclusions of valid arguments from that theory. • For the consequences of a theory to be observational, their truth or falsity can be directly decided by observations. Karl Popper (1902-1994 )

10. Falsification vs. Falsifiability (38) • Popper does not claim that a scientific theory must be actually false. He is claiming that a scientific theory must be falsifiable, i.e., must have observable consequences so that if these consequences are shown to be false, then the theory itself is shown to be false. • “The difference between being falsifiable and being false is like the difference between being vulnerable and actually being hurt.” (Kitcher, 38) • A good scientific theory is one that is empirically falsifiable but is not actually falsified. A bad scientific theory is actually falsified.

11. Falsification: An Alleged Example • Suppose we try to empirically falsify the theory that expresses the law of conservation of momentum. • This theory apparently has certain observational consequences: for example, the two cars will part in a particular way. • This is actually false, and this is the source of a major problem for the falsifiability criterion. We will come back to this point later. • Popper would claim that the theory is empirically falsified if the cars did not part that way. • The argument that would falsify the theory if the premises were all true: • “If the law of conservation of momentum is true, then the two cars will part in a particular way. The cars did not move apart that way. Therefore, the law of conservation of momentum is false.”

12. The Major Problem about the Falsifiability Criterion of Science (42-4) • Actually, many textbook cases of scientific theories are not falsifiable by themselves. • Why? Because observational consequences do not follow from these theories. • E.g.: merely from the Newtonian mechanics, predictions about the fall of an apple from a tree do not follow. Other things must be assumed to derive these predictions. • We discussed this point on Day 3. • The observational consequence, “Venus will show phases”, does not follow from the Copernican theory alone. • To derive this prediction by a valid argument, the premises of the argument must include not only the Copernican theory but also other assumptions: the telescope is a reliable instrument of observation; Venus lies between Earth and the Sun; and so on.

13. The Reality of the Falsification Argument • What argument could falsify the Copernican system? How about this? • If the Copernican system is correct,the telescope is a reliable instrument of observation, and Venus lies between Earth and the Sun, and so on, then Venus will show phases. • The Venus always appears crescent. C. Therefore, either the Copernican system is incorrect, the telescope is unreliable, Venus is not between the Earth and the Sun, or.... • If the second premise (as well as the first) were true, would this valid argument falsify the hypothesis that the Copernican system is correct? • No, because the conclusion is only that one of the assumptions – perhaps not the hypothesis – is false.

14. The Lesson and the Major Problem for the Falsifiability Criterion of Science • Textbook-cases of scientific theories, taken alone, do not have any observational consequences. • To derive an observational consequence from a theory and test the theory, we need auxiliary hypotheses – the premises stating the testing conditions (e.g., the telescope is reliable) and the premises stating theoretical background knowledge (e.g., the Venus lies between the sun and the earth). • Thus, we cannot falsify a theory by deductively valid argument alone. • Thus, if we apply the falsifiability criterion, respectable scientific theories turn out to be non-scientific!

15. A Possible Remedy? (p.43) • The textbook cases of scientific theories, combined with some auxiliary hypotheses, have observational consequences. • Therefore, the conjunction of the theories and the auxiliary hypotheses can be falsified. • So, why not modify the falsifiability criterion of science like this: a theory is scientific if and only if the theory, combined with some auxiliary hypotheses, has observational consequences (so that the conjunction of the theory and auxiliary hypotheses can be falsified)?

16. The Problem of the Remedy • Actually, combined with certain auxiliary hypotheses, any theory has observational consequences. Thus, the revised criterion makes any theory scientific. • Consider a guru’s theory, “Quietness is wholeness in the center of stillness.” Let me make T stand for this theory. • Guru has auxiliary hypotheses, such as “If T, then cherry blooms in the spring”, “If T, then bees gather pollen” and so on. • Then, the theory T, combined with these auxiliary hypotheses, has observational consequences. • For instance, from “T” and “If T, then cherry blooms in the spring”, we can derive the observational consequence that cherry blooms in the spring.

17. Why every theory turns out to be scientific? (Kitcher, pp.43-4) • Any theory statement can be coupled with other statements to entail observational consequences. • How? Given any theory T, and any statement O that predicts the result of an observation, we can make T to entail O by adding the auxiliary hypothesis, “If T, then O.” If T, then O T -------------- O • In the guru example, T is “Quietness is wholeness in the center of stillness”; and O can be “cherry blooms in the spring”, “bees gather pollen” and so on.

18. The Dilemma for the Falsification Criterion of Science: A Summary • Option 1: requires that a scientific theory by itself must have some observational consequences (so that the theory be falsifiable) • The Result: respectable scientific theories turn out to be non-scientific. • Option 2: requires only that a scientific theory, combined with some auxiliary hypotheses, must have some observational consequences (so that the combination of the theory and the auxiliary hypotheses be falsifiable) • The Result: every theory turns out to be scientific.

19. 3. Kitcher’s Three Criteria: a. Independent Testability • Remember the guru’s theory Q (“Quietness is wholeness in the center of stillness”) and his auxiliary hypotheses, for example, “If Q, then cherry blooms in the spring”. • Can we test these auxiliary hypotheses independent of Q? • No, because these hypotheses have observable consequences only in conjunction with Q. • Thus, a guru’s auxiliary hypotheses are not independently testable.

20. a. Independent Testability • On the other hand, the auxiliary hypotheses of a respected scientific theory are generally testable independent of the theory. • For example, as for the above-mentioned example of the Copernican theory, the auxiliary hypotheses (“the telescope is a reliable instrument of observation”, “Venus lies between Earth and the Sun” and so on) are testable independent of the Copernican theory. • Thus, Kitcher proposes the first criteria of science that the auxiliary hypotheses of a theory are testable independent of that theory.