S n SCIENCE, PHILOSOPHY OF question of what makes something a living organism, would turn out to be merely questions of degrees of Philosophy of science as an autonomous subject is a complexity and not specifically biological at all. In product of the twentieth century. Its development addition, the moral issues that pertain to humans and stemmed from the great intellectual challenges of the animals because of their psychological characteristics quantum and relativity theories of physics, but philosophical would be approached very differently if psychological issues surrounding such theories as psychoanalysis, evolu- properties were considered to be unreal or merely tionary theory, Marxist and capitalist economics, and the disguised biological properties. Differences between the ethics of human experimentation along with the enormous- sciences are methodologically crucial in this respect. For ly increased importance of science as an intellectual example, a great deal of medical research cannot enjoy the endeavor have led to a great expansion of the field. unlimited freedom of laboratory experimentation that is Work in philosophy of science tends to fall into two characteristic of physics simply because of the ethical approaches. The first sees science as a testing ground for constraints its subjects require. Moreover, the variability traditional philosophical problems. Chief among the of its subjects makes universal laws hard to formulate in traditional problems is this: Can we have any knowledge biology in distinction to, for example, astronomy. that is certain and in terms of which all other knowledge in the area can be justified (foundationalism), or are all claims to knowledge uncertain (fallibilism)? In the realm PREDECESSORS TO CONTEMPORARY of things that can be known by empirical investigation, it VIEWPOINTS would seem that science has the best claim to secure It was the logical positivists and logical empiricists of the knowledge. Philosophers of science have thus devoted a Vienna circle (1923–1936) and the Berlin school (1928– considerable amount of time to what kinds of scientific 1933) who succeeded in placing scientific issues near the methods are effective in producing such reliable knowl- heart of the philosophical enterprise. (A classic, albeit edge. In contrast, some philosophers have denied that sententious, presentation of the logical positivists’ views is science does actually produce a privileged body of in A. J. Ayer’s Language, Truth, and Logic, 1946 [1936].) knowledge and have argued that all scientific knowledge For philosophers such as Moritz Schlick (1882–1936), is a product of its historical and social context. Rudolf Carnap (1891–1970), Hans Reichenbach (1891– The second approach to philosophy of science focuses 1953), and Carl Hempel (1905–1997), all of whom had a on issues that are peculiar to individual sciences. Of scientific education, the task was to provide a foundation particular interest here is the possibility of reducing for genuine knowledge, and this foundation was to be as biology to chemistry or physics and of reducing some of secure as the best science of the time. The logical the social sciences, especially psychology, to biology. If positivists were squarely in the empiricist tradition, which these reductionist projects were to be successful, then holds that all genuine knowledge must be reducible in issues that appear to be peculiarly biological, such as the principle to knowledge obtainable by empirical methods 2883 (c) 2014 Cengage Learning. All Rights Reserved. Science, Philosophy of and, ultimately, to that obtainable through the human any observations whatsoever. To refuse to relinquish a sensory apparatus. To this empiricist view they added a theory in the face of recalcitrant data is a characteristic deep concern with language resulting from developments feature of scientific irrationality. Popper’s brand of in logic in the late nineteenth and early twentieth falsificationism is comprehensive, for it requires that even centuries. reports of observations be falsifiable. Thus in contrast to ’ Although the most famous manifestation of the the positivists foundationalism, which is grounded in an logical positivists’ approach was the attempt to eliminate empirical base that is certain, falsificationism is a deeply metaphysical claims through the verificationist criterion of fallibilist position in which claims to certainty are meaning (which asserts that a sentence is factually relinquished at all levels of generality. significant to a given individual if and only if that person Popper was well aware of a point often made by the knows what observations would lead him or her to accept French philosopher Pierre Duhem (1861–1916). To draw that proposition as true or to reject it as false), their true out testable predictions from scientific hypotheses, one legacy has been the view that it is by means of logical ordinarily needs to assume the truth of various back- analyses of philosophical concepts that genuine under- ground assumptions and theories (Duhem 1954 [1906]). standing is achieved. It is no exaggeration to say that Thus if the prediction turns out to be false, the force of philosophy of science in the years 1950 to 1980 was the falsification could be deflected away from the principal primarily engaged in a struggle to decide which elements hypothesis onto the background assumptions. Hence the of the positivist monolith to retain and what should be the need in the above specification of falsificationism to state replacement approaches for those parts that have been in advance what would result in the hypothesis being rejected. Since 1980 these general issues have been rejected. downplayed in favor of issues specific to individual ’ sciences. Although this strategy removes the force of Duhem s criticism that there are no crucial experiments that can conclusively decide between competing theories, it moves Falsificationism. An important alternative to the positivist the emphasis away from a method of testing that is based program has been the falsificationist approach of Karl R. – Logik der Forschung only on logic and empirical data to one where a (human) Popper (1902 1994). Although his decision plays a central role, and this introduces a (1959 [1934]) was published in 1934, its impact was characteristically conventional element into the picture. muted until the expanded English translation appeared in Falsificationism is primarily a normative methodology, for The Logic of Scientific Discovery 1959 as . Popper set it prescribes and proscribes courses of action with respect himself the task of providing a criterion that would to scientific hypotheses. As historical and sociological distinguish between genuine scientific hypotheses and studies of science have become increasingly influential, ’ pseudoscientific statements. A key belief driving Popper s there has been a concomitant emphasis on the need for work was his view that the traditional problem of methodological theories to be descriptively accurate of induction could not be solved. Most generally, inductive what scientists do and have done. It is easy to find cases inference involves reasoning from what has been observed where historically important episodes of science do not fit to what has not been observed, a characterization that the falsificationist model, cases where scientists refused to covers inferences from the past to the future, from abandon theories in the face of clear counterevidence. The observed data to the existence of directly unobservable difficult task is to articulate when this furthers broad microentities, such as prions, and from finite datasets to scientific ends rather than just narrow personal motives. the universal hypotheses that represent scientific laws and But to reject falsificationism merely because it is not general theories in epidemiology and elsewhere. descriptively accurate of everything done in the name of Justifying inductive inferences was a serious problem science would be as misguided as an attempt to turn ethics for logical positivism, because the verificationist criterion into a purely descriptive enterprise. ruled out all universal scientific theories and laws as meaningless simply because no amount of finite data Thomas Kuhn’s Work. One of the best-known alter- could conclusively verify these general claims. Popper natives to the positivist approach is that of Thomas Kuhn instead proposed the demarcation criterion that a (1922–1996). Ironically, Kuhn’s seminal work, The statement or theory was scientific only if it was falsifiable; Structure of Scientific Revolutions (2012 [1962]), was that is, it must be possible to state in advance a set of originally published as a volume in the positivists’ possible observations that, if observed, would result in the International Encyclopedia of Unified Science. Kuhn’s statement or theory being rejected. Theories such as strategy was to use the history of science as a proving astrology and psychoanalysis were, according to Popper, ground for methodological positions in the philosophy of branded as pseudoscientific on the basis of this criterion, science. This history, Kuhn claimed, could be divided into because they traditionally accommodated themselves to fit two distinct types of periods: long stretches of normal 2884 BIOETHICS, 4TH EDITION (c) 2014 Cengage Learning. All Rights Reserved. Science, Philosophy of science punctuated by brief periods of revolutionary experimental apparatus, and the verification or falsifica- science.