Main divisions of philosophy:

· metaphysics–deals with questions about what is real

· epistemology–deals with questions about what knowledge is and under what conditions we know something to be true

· ethics–deals with questions about morality and value (e.g., right/wrong and good/evil)

Hempel’s classification of the sciences:

I. empirical sciences–“seek to explore, to describe, to explain, and to predict the occurrences in the world we live in”

A. natural sciences–e.g., physics, chemistry, biology

B. social sciences–e.g., sociology, political science, anthropology, economics

II. non-empirical sciences–e.g., logic, pure mathematics

Purpose of Hempel’s book:

1. to examine how scientific knowledge is arrived at

2. to examine how scientific knowledge is supported

3. to examine how scientific knowledge changes

4. to consider how science explains empirical facts

5. to consider what kinds of understandings science’s explanations provide

6. to address questions about the presuppositions and limits of scientific inquiry, scientific knowledge, and scientific understanding

Assumptions:

1. The question of how scientific knowledge is arrived at is different from the question of how scientific knowledge is supported, and both are different from the question of how scientific knowledge changes.

2. Natural science explains empirical facts.

3. There may be more than one variety of understanding. Scientific explanation may provide understanding only with respect to some of those varieties.

4. There are certain presuppositions that scientific inquiry involves. There are also limits to what sorts of knowledge and understanding science can provide.

Hempel’s views on hypotheses

Hypothesis–an idea about how to explain some fact or set of

facts (e.g., Semmelweis’s explanation of the increased rate of deaths among women in the First Division of the Vienna General Hospital from childbed fever)

Deductive and Inductive Reasoning:

· Deductive—In “good” deductive arguments, it is inconceivable for all the premises to be true and the conclusion false.

· Inductive—In “good” inductive arguments, it is conceivable that all the premises are true and the conclusion false.

Forms of reasoning involved in the testing of hypotheses:

A. Deductive—

If hypothesis H is true, then so is test implication I.

Test implication I is not true.

Therefore, hypothesis H is not true.

B. Inductive—

If hypothesis H is true, then so is test implication I.

Test implication I is true.

Therefore, hypothesis H is true.

Two conceptions of scientific inquiry:

· “Narrow inductivist conception of scientific inquiry”:

(1) observation and recording of all facts

(2) analysis and classification of those facts

(3) inductive derivation of generalizations from the facts

(4) further testing of those generalizations

· “Wider inductivist conception of scientific inquiry”:

(1) identification of problems to be solved, questions to

be answered

(2) invention of hypotheses to solve problems, answer

questions; hypotheses must account for “relevant

facts”

(3) collection of additional facts to provide additional

inductive support or confirmation of hypotheses

According to Hempel, the “narrow inductivist conception of scientific inquiry” is flawed because—

A. It is impossible to collect and record all facts.

B. Facts are relevant or irrelevant only in reference to a given hypothesis; therefore, hypotheses must be formed before the collection of data.

C. The analysis and classification of facts also requires the prior formation of hypotheses.

D. There are no rules of inductive reasoning available that enable scientists to derive hypotheses from facts or data. Furthermore, no such rules are likely to be discovered.

E. Rules of inductive reasoning state criteria for the soundness of the inductive argument and assume that both the hypothesis and the data are given.