Course Outline for Philosophy 2233- The Earth and Life Sciences: Fall 2005
Instructor:
Bryson Brown, TH 222.
Phone: x2506 Email: brown@uleth.ca
Office Hours - Mondays and Wednesdays - 11 a.m. to 12 noon
One aim of this course is to study the relation between rational belief and scientific evidence. In
the seventeenth century it was fairly reasonable for a well-informed European to hold that the Earth was on
the order of six thousand years old, and that the various plants and animals we see were separately designed
and created. But today this view is regarded as naïve; most scientists (and well-informed people in general)
believe that the Earth is about 4.6 billion years old, and that life on Earth is descended from a common
ancestor dating back 3.5 billion years or more.
We will try to understand this change by examining the history of the earth and life sciences,
focusing on the arguments and evidence that have led us from a worldview based on Genesis to the
worldview scientifically accepted today. The first topic will be a historical examination of the development
of modern geology; then we turn to a study of the creation-evolution controversy, and finish with a
discussion of the relation between evolution and ethics.
Along the way we will consider some philosophical issues, including the nature and status of
evidence about the past, various accounts of scientific method including inductivism, falsificationism and
inference to best explanation, and links between scientific theories, naturalism, and wider questions
including ethics, religion and the meaning of life.
Evidence about past events can be extremely convincing, but we rarely ask ourselves what makes
it so convincing. Normally this doesn’t cause much trouble; common sense generally works pretty well all
by itself, without reflection on the hows and whys. But when we don’t understand how we come to have
the evidence we do and how it justifies our beliefs, we are often vulnerable to clever skeptical arguments.
Consider: Any evidence we have now about the past must be facts about the present— facts about things
like memory traces, inscriptions and recordings, fossils, fault lines, strata and their geological
arrangements, the light from distant stars and so on. So how do we justify the claim that this presently
available evidence reliably indicates how things were in the past? Don’t we need some further, more direct
evidence about how things worked in the past, to justify the claim that these present traces really provide
reliable information about the past? And if we do need such additional evidence, aren’t we reasoning in a
circle? We’ll examine this issue & consider carefully what sort of evidence we need to justify historical
claims. One lesson is that the popular creationist tactic of objecting to claims about the distant past because
there were “no witnesses” is a serious misunderstanding of how evidence about the past really works.
Scientific inquiry has led to rich and complex stories that constitute a history of the earth and of
life on earth. Understanding how we arrived at these stories requires careful thinking about how science
works. There have been many different philosophical answers to this question; we’ll examine some of
these. And here again we will find that creationist arguments depend on naïve misunderstandings of how
science works (especially common is insisting on standards of proof that no human knowledge could pass).
Induction is one important concept in the neighbourhood. Whenever we reason from what we
have observed to conclusions about the unobserved, we are doing inductive reasoning. Traditional
examples focus on generalizations that we make about objects of various kinds & how they behave under
various circumstances. Some of these are just plain part of common sense: we expect unsupported objects
to fall; we expect hot things to burn us if we touch them; we expect the foods that nourished us yesterday or
last week to do the same again today and tomorrow. Induction has often been described as a process of
“projecting” such observed regularities onto unobserved cases. But there are problems for this picture, as a
famous paradoxical argument from Goodman shows. And even if something like this picture is correct,
there are difficulties in understanding what reasons we could have for accepting it. It does seem that it has
worked in the past. But this is really just another observed regularity, and we need a reason to suppose that
this regularity will continue in the future, before it would be rational to accept that it will. This is the gist
of Hume’s famous argument that the past success of induction cannot provide non-circular reason to accept
induction. Since Hume also argued that there was no good deductive reason to suppose induction is
reliable, Hume concluded that our inductive reasoning is not rationally defensible, though he also believed
that we will do it anyway, because we are (in effect) programmed to reason inductively whether we want to
or not.
Karl Popper agreed that induction was indefensible, and concluded that science, properly
understood, shouldn’t use induction at all. Instead, he thought that it should use the method of falsification,
or (as he later put it) of ‘bold conjectures and refutations.’ According to Popper’s account of scientific
method, scientists make guesses about generalizations that might hold, and then test them as severely as
they can, trying to find ways to make them fail. The body of scientifically acceptable theories, from this
point of view, is really just a list of generalizations that haven’t been falsified yet.
But without some role for induction we are left with no justification for the commitments we make
to how things will turn out in the future—and all of our practical efforts seem to be based on such
commitments: When we design a bridge, plant a crop, or use a tool we assume that certain observed
regularities will continue, and we often bet our lives on it. So some account of induction is essential if we
are to have any account of why some practical decisions are rational and some are not.
More recently, some epistemologists have proposed inference to the best explanation as an
account of how we extend our observations to a justified story about the wider world. Some philosophers
of science have endorsed this appeal to explanation, while others have resisted, seeking a more traditional
account of the relation between theories and the observations that test them. But the role of explanation in
our understanding of the world goes right back to the roots of common sense; I believe that any account of
scientific method will need to recognize the importance of explanation to the justification of beliefs. A
successful account must also account for some important limits on the reach of explanatory hypotheses (as
the “god of the gaps” example shows). We’ll examine these debates & try to arrive at a broader
understanding of scientific method, with an eye to important examples from geology and biology.
Finally, many creationists have argued that ethics and evolution are somehow incompatible. One
of the key issues we need to explore here is how normative and descriptive concepts are related to each
other. Some have argued that they are completely distinct and independent, so it may turn out that there
can be no conflict between science and ethics: Ethics is essentially normative, while science aims to
provide correct descriptions of the world. But the descriptive and the normative may not be completely
independent, and evolution may have real implications for our understanding of ethics (the creationists’
incompatibility claim is still very hard to defend, even if we allow for some plausible connections). Here
S.J. Gould’s defense of the doctrine of “separate magisteria” will be examined, as well as Hume’s concerns
about the relation between normative and descriptive claims.
We have two main texts, as well as some further short readings. The texts are both available in the
bookstore: The Abyss of Time, by Claude Albritton, and Science on Trial, by Douglas J. Futuyma. Both
are sold as course-packs.
Other recommended readings:
A. Hallam, Great Geological Controversies, (Oxford, OUP, 1983).
R. Fortey, Trilobite! Harper Collins, 2000.
D. J. Futuyma, Evolutionary Biology 3rd ed., Sinauer 1998.
Stephen Jay Gould, Ever Since Darwin, The Flamingo=s Smile, Bully for Brontosaurus, Time’s Arrow,
Time’s Circle, Rock of Ages, Eight Little Piggies, The Lying Stones of Marakesh, Leonardo’s Mountain of
Clams and the Diet of Worms.
Rachel Laudan, From mineralogy to geology : the foundations of a science, 1650-1830, University of
Chicago Press, 1987.
John McPhee, Basin and Range, Rising from the Plains, In Suspect Terrain, Coming into the Country, and,
finally, Annals of the Former World Farrar, Strauss and Geroux, NY, 1998 (collects the others & more).
R. Pennock, Tower of Babel: The Evidence Against the New Creationism, MIT Press, 2000.
Michael Ruse, Darwinism Defended (Benjamin/Cummings, )
Steven M. Stanley, Earth and Life Through Time 2nd ed. W.H. Freeman & Co., 1989.
S. Winchester, The Map that Changed the World, Harper Collins 2001.
Phil 2233- Course Schedule and Grading Scheme
Course Schedule:
Phil 2233- Course Schedule and Grading Scheme
Course Schedule:
Week 1: Sept 7, 9: Introduction, overview of material: Change in view, evidence and reasoning, certainty and
skepticism. Nicholas Steno, Solids within solids and the principles of stratigraphy
Week 2: Sept 12, 14, 16: Two views on the nature of fossils; Kircher, Hooke. Reasoning about the past—memory
and other traces; the reliability of evidence about the past & our accounts of various processes.
Week 3: Sept 19, 21, 23: Two images of time: Time’s Arrow—Burnet, De Maillet, Buffon; Time’s circle—Hutton and
Playfair.
Week 4: Sept 26, 28, 30: William Smith and fossil stratigraphy: a new arrow of time. Evidence for Smith’s
hypothesis & its independence from evolutionary assumptions. Werner’s geognosy & the neptunist’s arrow.
Week 5: Oct 3, 5, 7: Uniformity principles: catastrophism vs. actualism vs. uniformitarianism, Cuvier, Scrope, and
Lyell. Methodological advantages of uniformitarianism. The ice age (Perraudin, Venetz, Charpentier & Agassiz) &
how theories become facts. The role of naturalism in scientific thought.
Sample questions for test 1 distributed October 7.
Week 6: Oct 12, 14: The Age of the Earth – Kelvin and the geologists. Conflict in science, and how to cope with it.
Radiometric dating. Plate tectonics.
Test 1- October 14.
Week 7: Oct 17, 19, 21: Introduction to evolution. Natural selection, its ingredients and conditions. The argument
from design (Paley & the neo-Paleyites). Hume’s objections to the argument from design; reflections on the difference
between the historical and theoretical sciences.
Week 8: Oct 24, 26, 28: Taxonomy & evolution—analogies and homologies; explaining homologies. Explanatory
success and evidence in science. (Confirmation, falsification and scientific method; explanations that rule out
alternatives vs. “anything explainers”.)
Week 9: Oct 31, Nov 2, 4: Evolution and the fossil record—missing links, transitional forms, and evolutionary
predictions. (Fair expectations and unreasonable demands; the game of selective skepticism.) Evolution and
biochemistry—a new argument for common descent. (Consilience of different sources of evidence; a sort of economy
of belief.)
Week 10: Nov 7, 9: Natural selection and adaptation; the role of chance in Darwin’s theory. The nature of science.
Sample questions for test 2- November 9.
Week 11: Nov 14, 16, 18: Creationism and creationist arguments; Behe, Johnson and intelligent design as
“respectable” creationism. Drawing the line between science and non-science: The status of the “ID” hypothesis.
Test 2- November 13
Week 12: Nov 21, 23, 25: Social Darwinism and its failings. Hume and the is/ought gap.
Week 13: Nov 28, 30, Dec 2: The evolution of altruism: kin selection, group selection, selfishness and selflessness,
genes and individuals.
Week 14: Dec 5, 7, 9: Ethics, values, and their relations to evolution and the natural world in general.
Sample questions for final.
Final exam not yet scheduled
Grades: Grades will be based on two term tests (35 % each) and a final exam (30%). The tests combine short answer
questions (answers to these should range between a single sentence and a paragraph in length) and essay questions
(answers to these should range from a couple of pages up). Short answer questions focus on the material covered in the
texts and lectures, while the essay questions provide an opportunity to show both a grasp of the material and the ability
to think seriously about it. Your personal views will not be part of the basis for your mark; your grasp of the material
and the arguments you offer will be. The final exam will have a similar structure, with short answer questions drawn
from the topics of the last few weeks (evolution and ethics, broadly) and essay questions ranging over the whole
course.
Policy On Academic Offenses:
Plagiarism and other forms of academic cheating are serious offenses (for definitions & further info, see
Student Discipline Policy in the University of Lethbridge Calendar). In the case of a first offense, a 0
mark will be entered for the test or assignment in question. In the case of a second offense, an F will be
entered as the course grade. In either case a notice will be added to the student’s file, and further action
may also result.