he job of philosophy is give us a variety of mutually incompatible frameworks in which to ask questions. If some branch of philosophy ever produced an actual answer to a question, it would automatically cease being philosophy and become a new branch of knowledge, and the philosopher would be immediately drummed out of the Philosopher's Union and sent packing. Thus it would be unrealistic to expect a definitive answer from philosophers to questions like, "What is science?" If they provided one, we might then need a philosophy of philosophy of science to describe it.
Nevertheless, philosophers have struggled with the question of what science is for almost two centuries. The pre-eminent philosopher of science, says the author, a professor at Stanford, was undoubtedly Karl Popper, who introduced the notion of falsifiability. Only theories that could theoretically be proved false, said Popper, were valid scientific theories. Conversely, a theory can never be regarded as "true" regardless of the number of times its predictions have been confirmed by evidence. Philosophers have found some problems with this approach, the main one being that some theories are regarded as having been proved. A theory that passes every conceivable test is canonized and elevated to the status of a "law." We never speak of the "theory of atoms" or the "theory of DNA replication" any longer.
Another famous philosopher of science was Thomas Kuhn. The sociological approach of Kuhn and those who followed had less influence on scientists than Popper; his biggest effect was to introduce the word "paradigm", which has plagued scientific papers ever since. The paradigm of scientists peppering papers with the word "paradigm" (often using the word in unique ways) seems finally to have shifted. Other views, such as those of the postmodern relativists, who believed that there was no such thing as truth, received mainly scorn from those few scientists who paid any attention to them. The notion that there is no such thing as absolute truth receives what is, from scientists, the ultimate put-down: it is simply false.
The book also discusses the work of other philosophers, some of whom have been engaged in raging battles about science, but whose ideas are mostly unfamiliar to scientists. The author tries to present each viewpoint fairly, by adopting a historical approach and avoiding controversy. The writing is clear and jargon-free, but without excessive depth, and has few actual examples of scientific controversies that would illustrate the concepts. There is also none of the usual elaboration of ideas, citations to philosophical journals, and slagging-off of other philosophers that one expects in a philosophy text. Nor does the author take any strong positions. His goal is to present a simple and readable introduction to beginning students.
Do we need a philosophy of science? The answer is unquestionably yes. A philosophy of science is one of the strongest weapons we have for identifying pseudo-science. To philosophers, the subject is fascinating because to them, science is a sort of "applied epistemology." This book is a well-written (except for occasional awkward phrases like "she or he") and balanced introduction to the subject.