Science and Worldviews

Transcription

1 Science and Worldviews

2 What is a worldview? A worldview is an interlocking system of beliefs about the world. A worldview provides a conceptual framework, or set of background assumptions, that is needed for science. The notion of worldview that DeWitt uses roughly matches what Thomas Kuhn calls a paradigm.

3 The first scientific worldview The first scientific worldview was developed by Aristotle. Here are some truths in this worldview: (a) The Earth is located at the center of the universe. (b) The Earth is stationary, that is, it neither orbits any other body such as the sun, nor spins on its axis. (c) The moon, the planets, and the sun revolve around the Earth, completing a revolution about every 24 hours. (d) Below the moon there are four basic elements, these being earth, water, air, and fire. (e) Everything from the moon up is composed of a fifth basic element, ether.

4 Aristotle s layered universe (not to scale) 4

5 An interlocking system The different beliefs in a worldview cannot be separated from one another too easily. Each belief in a worldview tends to make sense of, and give support to, the others. Changing one belief in a worldview often requires many others to be changed as well. (Like a jigsaw puzzle, or a crossword puzzle.)

6 Common Sense The worldview we are presently in strongly influences our thinking. It dictates certain beliefs as being obvious, common sense, and so on. from within the perspective of any worldview, the beliefs of that worldview will appear to be the obviously correct ones. (DeWitt, p. 16) Many things that seemed obvious to Aristotelians now seem crazy or weird to us!

7 Kuhn s gestalt shift metaphor for paradigm change e.g. the duck-rabbit 7

8 A Parable Alice s favourite area of study was Duck. So in grad school she quickly made it her main focus. She had always been fascinated by the posterior cranial indentation, or PCI, that small hole at the back of Duck s head. People couldn t understand her interest in it, dismissing it as an accident of nature, a pointless detail of no interest. And her supervisor, Dr. Gable, ruthlessly shot down her proposed topic. That s a silly choice for a promising young researcher, he said. You can t build a successful career on studying the PCI. You won t get funding, there aren t any good journals publishing on the PCI, it s a dead topic. 8

9 Reluctantly, therefore, she decided to work on the bill instead. Her investigations went badly however. Dr. Gable had steered her into devising more accurate techniques for measuring the hardness of the bill surface existing techniques had proved to be unreliable. But Alice s new technique, though it should have worked, she thought, gave results that couldn t be right. According to her data, the bill was extremely soft, far too soft to grip anything firmly. Dr. Gable was disappointed in her, but Alice refused to give up. She was sure that her method was sound, certain that the bill was indeed far softer than anyone realized. But how could the Duck bill be that soft? She started to think wild thoughts. Perhaps the bill wasn t a bill at all? 9

10 While Alice was browsing the internet, she came across a wacky piece by someone who claimed that Duck was really a rabbit. Normally she would just have laughed at the idea, but then it struck her that, on this view, the Duck s bill is really a pair of ears. That would explain the softness! The idea quickly took hold of her. She couldn t get it out of her mind. Obviously she couldn t share her idea with Prof. Gable. So she announced to her supervisor that since the hardness measurements were obviously not working, she would instead try to examine the fine structure of the bill surface. (This would enable her to test the ear idea.) The suggestion was not viewed favourably, but somehow she convinced him to let her try, for just a few weeks. 10

11 Her results were astonishing (at the time). Her protein analysis found clear evidence of hair, or at least hair-like structures. Dr. Gable was exasperated. Hair on Duck s bill, for God s sake! But after reviewing the data and her methodology, Gable reluctantly allowed her to publish her results, in the prestigious American Journal of Bill. The paper, authored by Gable and Grant (in that order) Anomalous Filamentous Structures in Bill Surface, generated some comment but was forgotten after a few weeks. 11

12 Secretly, however, Alice was doing some extra curricular reading. She found a couple of papers by a Swedish team on the posterior cranial indentation. (For some reason, Sweden seemed to be the one place where you could study PCI.) They had found oddities there as well, isolating a kind of enamel from samples drawn from the PCI. The team was unable to find a satisfactory explanation. Alice couldn t believe what she was reading she became breathless with excitement. There are teeth there! she yelled out loud. It s a freakin mouth, that s what it is! 12

13 Some twenty years after those heady days, Alice reflected on how the world had changed. Nobody studied Duck anymore, it was all Rabbit now. The battle had not been easy, it had taken many years, but one by one Duck researchers had gone over to Rabbit. In some departments the struggle had been rather bitter, with Duckists trying to oust their Rabbitist colleagues, and vice versa. But by this time the only Duckists left were irrelevant dead wood just a few years from retirement. It was impossible now to get a Ph.D. working on Duck. 13

14 The Case of Continental Drift Until as recently as 1960, mainstream science was adamant that the continents are fixed in place and never move, even though good argument for drift were made by Wegener as early as Drift was dismissed as Germanic pseudoscience, a fairy tale, etc.

15 Do scientists think for themselves? Or do they have to stick to the worldview that they were taught, and which the scientific community accepts?

16 There is a fundamental difference between religion, which is based on authority, and science, which is based on observation and reason. Stephen Hawking

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18 Kuhn on whether scientists think for themselves At least in the mature sciences, [the paradigm is] firmly embedded in the educational initiation that prepares and licenses the student for professional practice. Because that education is both rigorous and rigid, [the paradigm comes] to exert a deep hold on the scientific mind. we shall want finally to describe that research as a strenuous and devoted attempt to force nature into the conceptual boxes supplied by professional education (Kuhn, Structure, pp. 4-5)

19 Normal science, the activity in which most scientists inevitably spend almost all their time, is predicated on the assumption that the scientific community knows what the world is like. Much of the success of the enterprise derives from the community s willingness to defend that assumption, if necessary at considerable cost. Normal science, for example, often suppresses fundamental novelties because they are necessarily subversive of its basic commitments. (Kuhn, Structure, p. 5. Kuhn goes on to say that such novelties cannot be suppressed for very long, and they can lead to a scientific revolution or paradigm shift.)

20 The geosynclinal theory is one of the great unifying principles of geology. In many ways its role in geology is similar to that of evolution that serves to integrate the many branches of biological sciences. Just as the doctrine of organic evolution is universally accepted among thinking biologists, so also the geosynclinal origin of the major mountain ranges is an established principle in geology. Thomas Clark and Colin Stearn, The Geological Evolution of North America: A Regional Approach to Historical Geology, p.43 (Ronald Press, 1960)

21 Might our jigsaw puzzle, our worldview, turn out to be equally incorrect, even though our system of beliefs is consistent and seems to us to be obviously correct and commonsensical? (DeWitt, p. 16)