Philosophy of science is part of a range of sub-disciplines known as "philosophy of X" (where X may be filled in with art, history, law, literature, or the various special sciences such as physics). Each of the activities for which there is a "philosophy of X" is an investigation into a certain part of the world or a particular type of human activity. What we will talk about today, in very general terms, is what distinguishes philosophy of X from sociology, history, or psychology of X. These approaches to science cannot be sharply demarcated, though many people have thought that they can be. However, there are clear differences of emphasis and methods of investigation between these approaches that we can outline here in a preliminary way.

Let us attempt to characterize the particular emphases of several approaches to studying science:

• Sociology of Science - Sociology of science studies how scientists interact as social groups to resolve differences in opinion, how they engage in research, and how they determine which of many theories and research programs are worth pursuing, among other things.
• Psychology of Science - Psychology of science studies how scientists reason, i.e., the thought processes that scientists follow when they are judging the merits of certain kinds of research or theoretical speculations; how they reason about data, experiment, theories, and the relations between these; and how they come up with new theories or experimental procedures.
• History of Science - History of science studies how scientists have engaged in the various activities noted above in the past, i.e., how social interactions among scientists (and between scientists and the greater society) and styles of scientific reasoning have changed over the centuries; and how particular scientific achievements came to be accepted, both by individual scientists and by the scientific community as a whole.

In each of these cases, the data on which the approach to studying science is based is empirical or observational. What is at issue is how scientists in fact interact as social groups, reason, or how scientific reasoning styles and scientific theories have in fact changed over time. To adjudicate disputes within these approaches thus requires engaging in much like scientific activity itself: one must gather evidence for one's views (or in the case of certain approaches to history, one's interpretation of the nature of scientific activity or the causes of scientific revolutions).

What is philosophy of science? How does it differ from these other approaches to studying science? Well, that's not an easy question to answer. The divisions among philosophers of science are quite striking, even about fundamentals, as will become apparent as the course proceeds. One reason for this is that philosophers of science, on occasion, would find many of the things that sociologists, psychologists, and historians of science study to be relevant to their own studies of science. Of course, the degree to which philosophers of science are interested in and draw upon the achievements of these other disciplines varies greatly among individuals--e.g., some philosophers of science have been far more interested in the history of science, and have thought it more relevant to their own endeavors, than others. However, there are some tendencies, none of them completely universal, that would serve to mark a difference between philosophers of science on the one hand and sociologists, historians, and psychologists of science on the other.

The first difference is that philosophy of science is not primarily an empirical study of science, although empirical studies of science are of relevance to the philosopher of science. (Like everything else you might cite as a peculiarity of philosophy of science, this point is a matter of dispute; some philosophers of science, for example, claim that philosophy of science ought to be considered a special branch of epistemology, and epistemology ought to be considered a special branch of empirical psychology.) Philosophers of science do not generally engage in empirical research beyond learning something about a few branches of science and their history. This type of study, however, is simply a prerequisite for talking knowledgeably about science at all. Philosophers primarily engage in an activity they call "conceptual clarification," a type of critical, analytical "armchair" investigation of science. For example, a philosopher of science may try to answer questions of the following sort.

What is scientific methodology, and how does it differ (if it does) from the procedures we use for acquiring knowledge in everyday life?

How should we interpret the pronouncements of scientists that they have gained knowledge about the invisible, underlying structure of the world through their investigations?

Part of what is open to philosophy of science, insofar as it is critical, is to question the methods that scientists use to guide their investigations. In other words, philosophers of science often seek to answer the following question.

What reason is there to think that the procedures followed by the scientist are good ones?

In a sense, philosophy of science is normative in that it asks whether the methods that scientists use, and the conclusions that they draw using those methods, are proper or justified. Normally, it is assumed that the methods and conclusions are proper or justified, with it being the task of the philosopher of science to explain precisely how they can be proper or justified. (In other words, the philosopher of science seeks to understand the practice of science in such as way as to vindicate that practice.) This opens up the possibility of revision: that is, if a philosopher of science concludes that it is impossible to justify a certain feature of scientific practice or methodology, he or she might conclude that that feature must be abandoned. (This would be rare: most philosophers would react to such a situation by rejecting the view that did not vindicate that feature of scientific practice.)

Let us take another approach to the question of what distinguishes philosophy of science from other approaches to studying science. Philosophy has, since Plato, been concerned with the question of what a particular kind of thing essentially is. In other words, philosophers seek a certain sort of answer to questions of the following form.

In asking a question of this form, philosophers seek to understand the nature of X, where by "nature" they mean something like X's essence or meaning.

We will start the course by considering the question, "What is scientific explanation?" We will also seek to answer the question, "What makes a scientific explanation a good one?" Most people take the notion of explanation for granted; but as you will soon find out, philosophers take a special interest in the concepts others take for granted. Philosophers emphasize the difference between being able to identify something as an explanation and being able to state in precise terms what an explanation is, i.e., what makes something an explanation. Philosophers seek to do the latter, assuming that they are able (like everyone else) to do the former.

None of this, of course, will mean very much until we have examined the philosophy of science itself, i.e., until we start doing philosophy of science. To a large degree, each of you will have to become a philosopher of science to understand what philosophy of science is.