Philosophy 1103: Introduction to Philosophy of Science

Langara College Department of Philosophy Instructor: Richard Johns

Problem Set 3

Hand in answers to the following questions in class on Wednesday, March 7

1. The following passage contains material from “A History of the Collapse of Flood and a Young ” by Davis Young. In reading this it’s important to know that sedimentary is created at the bottom of oceans and lakes. (Mud, dead animals, etc. in the water settle to the bottom, forming layers that get compressed, and turn eventually into rock.) Rock that is on land is gradually eroded by wind, rain, frost, rivers and glaciers.

Prior to around 1650, most scientists believed in a universal flood that covered the whole earth (described in the Bible) for perhaps a year, a few thousand years ago. The earth was believed to be less than 10,000 years old. The flood was responsible for most geological formations, including the layers of seen all around the world. The flood theory was supported by some evidence, such as the discovery of fish fossils at the tops of mountains, indicating that those areas were once under water. Also, many tribes (the Arabs, Chinese, Mexicans, Peruvians, and Brahmins) had a legend of a massive flood long ago.

During the 18th century, however, new evidence caused most scientists to think that Noah’s flood was less significant in geology. Here are some of the relevant findings and the problems they caused.

James Hutton (1726-1797) pointed out cases where relatively horizontal rocks overlie the evidently eroded edges of steeply tilted layers. Hutton argued that such phenomena were evidence for important revolutions in earth history. The older strata (layers) had been consolidated, tilted on edge, uplifted toward the surface, eroded to form a land surface, then submerged beneath the sea and buried under newly deposited marine sediments. In other words, the rock sediments were not all laid down at the same time, during a single flood.

Lehmann, Fuchsel, and Pallas discovered that rock strata occurred in orderly sequences, that European sequences of strata were commonly thousands of feet thick, and that in many instances individual layers could be traced horizontally for tens or hundreds of miles. The thickness, extent, and orderliness of the stacks of layers were increasingly difficult to account for in terms of a single, brief, chaotic, turbulent flood.

Various alternative theories were proposed, including “Neptunism”, the idea that most of the earth’s geology could be explained in terms of the gradual diminishing of a vast primeval ocean that initially covered the entire earth. Another idea, “”,

1 stressed the importance of volcanoes in geology, and involved the claim that during the earth’s history there were interchanges of land and sea, so that a given region would be under an ocean for a while, then be raised up to become dry land, then sink down under an ocean again, etc. Both these new theories required the earth to be very old, and had at best a minor role for Noah’s flood. Neptunism faced the problem of where all the water of the primeval ocean went, and Plutonism was challenged to explain how ocean beds were sometimes forced upwards, eventually becoming mountain peaks.

(i) Summarise the relevant data (geological or otherwise) mentioned in the passage above, in point form. [3 marks]

(ii) Briefly describe the three hypotheses mentioned that were used to explain these data. [3 marks]

(iii) How plausible was each theory? (Point out any aspects that seem inherently plausible/implausible to you, or which would have seemed plausible/implausible in the 18th and 19th centuries.) [3 marks]

(iv) How well did each theory predict the data, overall? Explain your answers. [6 marks]

2. Thomas Kuhn claims that science isn’t nearly as cumulative as is commonly believed.

(i) What is meant by science being cumulative? [2 marks]

(ii) According to Kuhn, how do history of science textbooks create the illusion that science is more cumulative than it really is? [3 marks]

3. In “Objectivity, Value Judgment and Theory Choice” Kuhn states five criteria that scientists use to judge between competing hypotheses.

(i) List these five criteria. [3 marks]

(ii) Assuming that scientists agree on these criteria, why is theory choice still less than fully objective, according to Kuhn? [3 marks]

(iii) During the Copernican revolution, which of the criteria did the Copernicans especially appeal to? Which did the Ptolemaic scientists appeal to? [4 marks]

2 4. Most of the responses we looked at to Hume’s problem of induction seemed to require some form of synthetic a priori knowledge (i.e. innate, or “hard wired” knowledge of matters of fact).

(i) Describe why this is. I.e. explain why appealing to probability theory, inference to the best explanation, or the uniformity of nature seems to require that some things are known a priori. [4 marks]

(ii) Ladyman writes, “From the modern perspective, Kant’s belief in synthetic a priori knowledge seems hopelessly optimistic.” Why do most philosophers reject the idea that science requires some a priori knowledge? Do you agree? [3 marks]

(iii) Is there a plausible evolutionary origin for such a priori knowledge? Briefly explain your answer. [3 marks]

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