Feb. 24th, 2011
Chapter 17- Bas van Fraassen’s The Pragmatics of Explanation
Presenter: Luke
Notetaker: Rick
Luke: van Fraassen was attempting to debunk previous theories of explanation. While
he rejects all the other alternatives for scientific explanation, he says that “there are no
explanations in science.”
Sansom: The received view of scientific explanation was that we choose theories
because they have explanatory power, or that explanatory power is a feature of a theory. Van
Fraassen disagrees with the received view in that he does not take explanation to be a power or
capacity of theories; explanation requires a theory, but theories do not explain things.
A theory is true because it has a relationship to the world. This is empirical adequacy or
something like a classic correspondence theory of truth. But this truth, the theory and the
configuration of the world taken together, does not explain anything. Rather, explanations
occur in the context of specific questions.
Luke: What are the broader implications of van Fraassen’s view? Van Fraassen believes
that this undermines certain philosophies of science.
Sansom: What is a contrast class? When the question is asked, “Why did I have a
sandwich for breakfast,” is this a question about a sandwich, or about breakfast, or about “I”
instead of someone else? What is the best way to pick out the response which will properly
answer the question being asked? A why-question does not necessarily reveal the contrast
class, but when giving an explanation, one needs to know the proper contrast class. In normal,
everyday communication, contrast classes are usually understood, even if only implicitly. (This
entire discussion is absent from Hempel’s notion of explanation.)
Consider this question: “Why do stars move behind the sun during an eclipse?” This
contains an implicitly understood contrast class, namely, that the stars appear to be moving
rather than the sun. But one can imagine that we could mean to ask “Why did the sun move
during the eclipse?” This is a stretch, but this demonstrates how important it is to understand
the question accurately. Concerning Hempel we can ask if his account provide an explanation
for every contrast class possible?
Question: What role do theories play in a successful explanation if it is not the theories
themselves which do the explaining?
Sansom: Theories + appropriate use + the pragmatics of the situation (the dynamic of
why-questions and contrast classes) = explanatory power
[At this point the class read the section “Simple Pleasures” from the chapter]
-When you adopt a theory, some things necessarily get pushed aside, since every theory has a
proper scope.
- A theory tells you which facts explain which facts.
-The question determines which theories we choose. (Anton)
Sansom: To say that a theory has control power is weird. Saying that a theory has explanatory
power is equally weird. This usage is a personification of the theory.
Luke: Did people ever actually attribute this anthropomorphism to theories?
Sansom: The personification of theories as having powers or capacities is not just an
issue of semantics. It would be the wrong understanding of van Fraassen’s work to assume he
merely wanted scientists to be more careful about how they speak about theories. Even
changing the language to “theories grant us the power to explain events” rather than “theories
explain events” is to misunderstand van Fraassen’s true intention.
Cody: This all suggests that what counts for explanatory adequacy comes from outside
the theory. Can you be a realist and accept van Fraassen’s view?
Ross: Van Fraassen’s notion of explanation does not stop the general goal of scientific
pursuit, which is to understand the nature of the universe. There will still always be an infinite
regress which demands explanation of something else.
Sansom: Contrast classes may prevent the regress.
Cody: When your children ask the question, “Where do babies come from,” you don’t
say, “The Big Bang.” This is because you understand the proper contrast class of the question;
hence, no regress.
Sansom: If every explanation is a why-question and every why-question has to have a
contrast class, if someone asks what the fundamental nature of the universe is, does he get his
question answered? A scientist will always ask for the contrast class because a well formed
question is one with a clear contrast class.
Sansom: In science, do we ask questions that do not have contrast classes?
Ross: Matters of contingency will always have contrast classes. Matters of necessity will
not. Maybe issues of necessity are outside the bounds of science.
-Since science investigates empirical matters (contingencies), there should always be a proper
contrast class for any scientific question.
Anton: How does all this resolve asymmetry problems?
Sansom: Are all asymmetries the result of our theories? Is the flagpole asymmetry
because of our theory? Contrast classes become very important for resolving asymmetries.
Our theory is going to tell us which side of the asymmetry is important to address.
Question: What is the difference between answering and explaining?
Sansom: Which is the highest mountain? By calculating the height of the highest
mountain, has a person explained anything?
Both Copernican and Ptolemaic theories were equally empirically adequate in that both
theories could calculate the position of the planets. But only Copernicus could explain why
outer planets moved more slowly around the sun.
Question: What is the difference between calculation and explanation?
A calculation is part of a scientific explanation.
Cody vs. David
Cody asserts that contrast classes are essential for explanation.
David asserts that if one could provide a detailed enough picture of the world, then it would
address every possible contrast class for a given question.
Sansom: You can always identify more contrast classes for a why-question, so while David’s
option may be ideal, it is not possible.