Se ha denunciado esta presentación.
Utilizamos tu perfil de LinkedIn y tus datos de actividad para personalizar los anuncios y mostrarte publicidad más relevante. Puedes cambiar tus preferencias de publicidad en cualquier momento.

Part 5: Philosophy of Science: Demarcation

913 visualizaciones

Publicado el

Philosophy of Science: Demarcation

Publicado en: Educación
  • Sé el primero en comentar

  • Sé el primero en recomendar esto

Part 5: Philosophy of Science: Demarcation

  2. 2. SO FAR… • So far… • In part 1, we saw how formal logic works • We’ve seen some fallacies. • We’ve seen the difference between induction, deduction and abduction. • In part 2, we identified that induction is fallacious (logically) • We saw that there’s a problem of induction which says that we can’t generalise (past to future, token to type, etc) • Yet science generalises.
  3. 3. SO FAR… • So far… • We saw that we can instead argue that science uses probability claims • We saw how Bayes’Theorem works • And we saw some problems with it, like how to fix the prior probabilities. • We saw that we can fix the priors with frequentism or propensity. • We saw that background knowledge can influence believability. • We saw that there’s a problem with deciding what evidence is relevant.
  4. 4. SO FAR… • So far… • Then, in part 3, we saw how science tries to explain observations.We saw that • There’s a problem with the notion of causation • That we need to distinguish causation and correlation • There’s a question of curve-fitting, simplicity, predicting evidence, theoretical fit, and extrapolation
  5. 5. SO FAR… • So far… • Then we saw the problem of underdetermination of theory by evidence and • Occam’s Razor and Simplicity and • Other measures of a good explanation and • The problem of theory-laden observations.
  6. 6. SO FAR… • So far… • In part 4, we saw the realism vs instrumentalism debate: • That realism is the view that science is finding truth • That the No Miracles Argument says science wouldn’t be successful if it wasn’t finding truths • And thatVerisimilitude says that science is finding something “like” truth, and it’s getting better all the time.
  7. 7. SO FAR… • So far… • But then we saw that instrumentalism is the view that science ought to be pragmatic and stick to producing useful formulas, etc., not ‘truth’, • That we have paradigm shifts and so science is never fixed, • That there may be hidden variables that explain anomalous sciences that seem detached from the familiar operations of the physical world, and therefore, that realism might be rescued, and lastly • That realism can be used to impose a ‘scientific’ perspective on other cultures.
  8. 8. INTRODUCTION • In this part, we ask: What is science? • In this final part, we discuss how science is demarcated from non- science and pseudo-science, and • What practical problems may arise from science.
  9. 9. THE DEMARCATION PROBLEM • What is science and why do we care? • If science is successful, and other disciplines and research areas want to partake in that success, they ought to imitate the scientific method, so as to get the same levels of success. • We also want to be able to tell inductively bad arguments from inductively good arguments. • We want to be able to decide what is “expert testimony” in a court, e.g. from a psychiatrist or ballistics expert, as opposed to a layperson’s opinion.
  10. 10. THE DEMARCATION PROBLEM • So what is science? • So what makes a claim or theory scientific? Is it because it is a claim about the physical world? If so, some forms of psychology, and string theory, might not be science. • Or is it a claim about what is known to be true? If so, quantum mechanics isn’t scientific, because we can’t give true final statements about electrons’ energies or velocities or momenta or positions, all at the same time.
  11. 11. THE DEMARCATION PROBLEM Phenomenon Science Non-science Apparent planetary influences. Astronomy Astrology Cure of disease Medicine, physiotherapy Homeopathy, acupuncture, reflexology, chiropractic Personality Psychological theories of personality Astrology The behaviour of numbers Mathematics, topology, etc. Numerology The existence of the universe Cosmology, astronomy, physics Creationism Life Evolution, abiogenesis Creationism, Intelligent Design, Elan Vital Consciousness Neuropsychology, neuroscience, etc Soul theory, substance dualism, religion Chemicals’ behaviour Chemistry Alchemy
  12. 12. THE DEMARCATION PROBLEM • Bad Science, Non-science, Pseudoscience • Bad: trying to do science and failing, or, fraud. E.g. showing that Au is element 35. • Non-science: doesn’t cover things relating to science, so, most areas of philosophy, theology, art. • Pseudo-science: Looks like science, but isn’t. E.g. astrology, homeopathy, etc.
  13. 13. THE DEMARCATION PROBLEM • Scientific Attitude • Merton for example, identifies the scientific attitude as being one of universalism, communality, disinterestedness or objectivity, and organised skepticism. • But it speaks more to what a scientist is, than what makes a scientific theory scientific. Perhaps the best we can draw from this is that science is any theory that is objective or free from cultural particulars, and which is the result of skeptical inquiry. However, it is unclear whether anyone can be culturally neutral in all cases.
  14. 14. THE DEMARCATION PROBLEM • Demarcation of science • Here are some possible criteria to demarcate science. • We discuss each in turn.
  15. 15. THE DEMARCATION PROBLEM • Demarcation of science • It deals with empirical phenomena (as opposed, say, to spiritual phenomena) • It measures the physical world objectively
 and conducts experiments • It proposes theories to explain those 
 phenomena • It is based on mathematics • It has “laws” which describe how the 
 universe works
  16. 16. THE DEMARCATION PROBLEM • Demarcation of science • Its success rate is high (its predictions almost always work) • It is revisable, and its theories change or adjust as new information comes in; fallibilism, in short, is a marker of science • Its theories are testable • It may be said to be inductive • It provides epistemic warrant • It is timelessly useful or true
  17. 17. THE DEMARCATION PROBLEM • Demarcation of science • Each of these have some problems.
  18. 18. THE DEMARCATION PROBLEM • Demarcation of science • It deals with empirical phenomena. Not only - we can investigate anything. E.g. spirituality in the brain. • It measures the physical world objectively (as opposed to subjectively) and conducts experiments. Ideally, yes, in practice, objectivity is difficult. • It proposes theories to explain those phenomena. No, theology has theories. • It is based on mathematics. Not all. E.g. Evolution (originally), tectonics. • It has “laws” which describe how the universe works. Other disciplines, e.g. astrology, claim to have laws.
  19. 19. THE DEMARCATION PROBLEM • Demarcation of science • Its success rate is high. Trouble is, discarded theories were once considered ‘successful’. • It is revisable, and its theories change or adjust as new information comes in; fallibilism, in short, is a marker of science. This is a key claim, supported by Popper. • Its theories are testable. This is mostly correct, except String Theory* • It may be said to be inductive. Hempel disagrees. • It provides epistemic warrant. Perhaps, but the instrumentalists disagree. • It is timelessly useful or true. This is false; what is now science may later be nonsense.
  20. 20. THE DEMARCATION PROBLEM • Demarcation of science: Newton-Smith, Popper and Hempel
  21. 21. THE DEMARCATION PROBLEM • Newton-Smith • Verisimilitude.We’ve already seen problems with that.Also, philosophy is verisimilitudinal. • 1. Observational nesting refers to “replicating the observational successes of another theory as well as improving on them” (ibid). However, some theories make predictions of new observations that would otherwise have not been expected or even noticed, such as gravitational lensing and StringTheory, and they’re not really Newtonian or Quantum Mech.s. • 2. Fertility. It is true that scientific theories yield further scientific theories. So, Newton’s laws of motion ultimately led to Einstein’s Relativity; Bohr’s model of the atom ultimately led to Quantum Mechanics, and so on. However, fecundity is not the sole preserve of science. E.g.Aquinas and Catholicism.*
  22. 22. THE DEMARCATION PROBLEM • Newton-Smith • 3. Track record.Whether something has thus far proven a good theory is no sign that it is in fact a scientific theory or a good theory, especially if it is irrefutable.Theism, for example. • 4. Inter-theory support with existing theory.This criterion is correct. So, for example, Le Châtelier’s theory works well within the context of thermodynamics and chemistry. However, a theory can fit in well with existing theory and still be false (think of Bohr’s atom), and there can be non-scientific systems of thought with coherent theoretical models (think of astrology and theism here).
  23. 23. THE DEMARCATION PROBLEM • Newton-Smith • 5. Smoothness. If a theory responds well to changes, this is I believe a good marker of a theory being scientific. • 6. Internal consistency.This is similar to (4) above and takes the same considerations.Theism is consistent. If we consider the sciences as a whole. Biology is coherent with chemistry, and chemistry is coherent with particle physics. However, this raises the question of what theory was the first scientific theory, if a pre-existing scientific theory is required to demarcate a new theory as scientific.
  24. 24. THE DEMARCATION PROBLEM • Newton-Smith • 7. Compatibility with well-grounded metaphysical beliefs.This one, like consistency above (4), is problematic. It also begs a question of which metaphysical beliefs are well-grounded. So, theism is well-grounded, if one considers the vast literature supporting it.Also, which beliefs were the first well-grounded ones? • 8. Is simple. Swinburne (2004) argues that theism is simple.And we’ve seen the debate about what “simple” means. Quantum mechanics isn’t ‘simple’. • Are these criteria necessary, sufficient, or jointly necessary and sufficient?
  25. 25. THE DEMARCATION PROBLEM • Popper • Science is about “conjectures and refutations”. * • “Statements or systems of statements, in order to be ranked as scientific, must be capable of conflicting with possible, or conceivable observations” (Popper 1962, p39). • “A sentence (or a theory) is empirical-scientific if and only if it is falsifiable”. (Popper, 1989, p82).
  26. 26. THE DEMARCATION PROBLEM • Popper • Criticisms • Consider the case of the irregular orbit of Uranus. It didn’t follow the normal elliptical orbit, but had an aberration.This did not mean that, now that we’d found counter-evidence to the claim that planets’ orbits trace out ellipses. • Likewise for the precession of Mercury, where existing Newtonian mechanics saw it losing degrees of arc as it travelled around the sun. Instead of discarding existing astronomy, we adopted Einstein’s modifications.
  27. 27. THE DEMARCATION PROBLEM • Popper • Criticisms • Scientists don’t act as if they’re proposing a theory and trying to refute it. Generally, they’re seeking evidence to support it, or, they’re inferring a theory from “neutral” observations. • Popper’s falsification generally doesn’t happen in what Kuhn calls ‘normal science’, where people operate within existing theories.That being said, it means that ‘normal science’, e.g. work done in a chemistry lab, is not science (because nothing is being falsified), and only revolutionary science, e.g. when a theory is overthrown, such as Einstein’s case — only that, is science.
  28. 28. THE DEMARCATION PROBLEM • Popper • Criticisms • Lakatos argues that if Popper is right, we can get non-scientific theories that are scientific, and scientific theories that are non-scientific. (Lakatos 1981, p117). • So, for example, if StringTheory cannot be falsified, it is unscientific, whereas if Astrology can be falsified, it is scientific. • Lakatos, instead, argues that progress in science is made when theories make surprising predictions that are confirmed, and the ‘content’ of the theory is increased.
  29. 29. THE DEMARCATION PROBLEM • Hempel • Hempel proposed what is known as the deductive- nomological (DN or D-N) model. • What makes science different is that science postulates a hypothesis (or law), and, from that law, which is usually expressed mathematically, we can deduce (or predict) what events or data will occur when we measure.Thus, we deduce (predict) from the law (nomos, in Greek). Not inductive
  30. 30. THE DEMARCATION PROBLEM • Hempel • Hempel’s motivation for proposing DN seems to be about ‘expectability’ of events, given determinism and causation, that is, that unless we have a deterministic explanation for something, it is not explained. • Laws of optics entail that light will refract in a certain way* ; we can deduce the position of planets given Kepler’s laws, Newton’s laws, etc.*
  31. 31. THE DEMARCATION PROBLEM • Hempel • Criticisms • For “normal science”, say, where we are confirming Newton’s laws of motion, he seems to be correct. • However, in the case of new science, where we are going to propose a new theory, it is less clear that we’re using the DN model. General Relativity, say. You can’t deduce out of non-existing laws.
  32. 32. THE DEMARCATION PROBLEM • Hempel • Criticisms • Consider again the case of Boyle’s Law. It was first observational, and wasn’t based on existing law. • Secondly, it’s hard to say how a scientific law differs from a true contingent generalisation, such as “all presidents of USA are and have been men”. If D-N is correct, we could deduce that all future presidents would be men. Hempel takes them to be ‘exceptionless generalisations’ but we can think of many such cases which we don’t want to call laws.
  33. 33. THE DEMARCATION PROBLEM • Hempel • Criticisms • Third, it seems to require determinism, which means that chaotic and quantum-random events may not be well-explained by laws. Meteorology, economics, Brownian Motion, fluid flow turbulence, and so on would be unscientific. • But Hempel does recognise “inductive statistical” IS explanations. However, it’s unclear whether this is compatible with DN or a necessary or sufficient condition for scienciness.
  34. 34. THE DEMARCATION PROBLEM • Hempel • Criticisms • Explanatory asymmetries may arise. So, we can perhaps explain a phenomenon by reference to laws and initial conditions, but the laws themselves remain unexplained, and we can’t deduce the laws from the observations. Boyle again.
  35. 35. ETHICS AND SCIENCE Technology or Theory Reason it exists Benefit Problem Nuclear Power Einstein’s theory of relativity and atomic physics led to it. Nuclear power stations generate little waste compared to the amount of energy they produce Radioactive waste Nuclear weapons of mass destruction; over 60 000 people killed in each bombing Eugenics and Racialism Scientific studies of phenotypes in the 19th century created theory of racialism (races are real biological phenomena) Purportedly to understand human origins Racism justified by science on spurious evidence Supported Nazi doctrine GMOs and Genetic Modification: Designer Genes Once we understood DNA we could modify it Curing genetically inherited diseases in humans Making mosquitoes extinct. Increases rich/poor genetic divide through designer genes Fears around GMO food safety (unwarranted accordingAnimalTesting Considered unethical to test on humans Fewer humans harmed in scientific experiments Unethical ICTs Result of computer sciences ICTs have changed our lives in terms of how we conduct commerce, communicate and learn Espionage via back doors in software for autocratic or oligarchic states; no more privacy (1984)
  38. 38. ETHICS AND SCIENCE “My other suggestion is in an attempt to solve the problem of irresponsible people and especially those who are poorly endowed genetically having large numbers of unnecessary children. Because of their irresponsibility, it seems to me that for them, sterilization is the only answer and I would do this by bribery.” (Francis Crick).
  39. 39. • Cultural imperialism • If our science is true, and yours is false, can we impose it on you? • How about testing Muthi for efficacy in an RCT? ETHICS AND SCIENCE
  40. 40. ETHICS AND SCIENCE • Objectivity vs Cultural Relativity • Desmond Morris’ Naked Ape normalises western heterosexual practices as neutral observables, implying that other practices are neither normal nor proper objects of study. Naive monoculture. • Good reason to defend objectivity, #1: But normalisation of sexualities with scientific explanations can also help promote tolerance, e.g. claiming that it is genetically determined.
  41. 41. ETHICS AND SCIENCE • Objectivity vs Cultural Relativity • Good reason to defend objectivity #2. If a Nazi defends eugenics on the basis of racialism*, we can claim that there is no scientific objectivity to the doctrine (racialism), and therefore it ought to be discarded.
  42. 42. ETHICS AND SCIENCE • Thanks! • questions: