1
INTRODUCTION:
WHERE DO WE STAND?
1.1 Tasks and Aims of Philosophy of Science
Science plays a determining role in the life of today's society. In what sense and to what degree can we trust the results of science? There is a scientific discipline, which examines such questions systematically: the Philosophy of Science, which in the German language is called âWissenschaftstheorieâ (âTheory of Scienceâ). Following the German usage of the word, I always understand âscienceâ (âWissenschaftâ) in its broad meaningâincluding, besides natural sciences, also social sciences, humanities, etc.
The discipline of philosophy (or theory) of science investigates how scientific knowledge worksâits goals and its methods, its achievements and its limitations. Like any other scientific discipline, philosophy of science has historically developed out of philosophy. In the present days it is practiced both by philosophers and by scientists of various disciplines.
One distinguishes between the general philosophy of science, and philosophies of particular sciences. The latter ones are concerned with special kinds of disciplines such as philosophy of physics, biology, psychology, the social sciences or the humanities. The general philosophy of sciences discovers those components of knowledge that are more or less common to all scientific disciplines. Its main questions are:
1How is a scientific language constructed?
2What are the rules of correct scientific reasoning, or argument?
3What are the distinctive features of a scientific observation or âdatumâ?
4What is a scientific law, and what does a scientific theory consist of?
5How are law hypotheses and theories empirically tested? When do they count as confirmed, and when as refuted? What are the criteria for scientific progress?
6What is achieved by a scientific explanation and what is causality?
This book focuses on these questions of the general philosophy of science, and the following chapters are arranged in corresponding order to the above questions. At the same time, we shall also deal with applications and topics of the philosophies of particular sciences, and examine characteristic differences between different branches of science. The most general questions of philosophy of science include:
7 Is there an objectively discoverable reality, and an objective truth?
8 What connection exists between science and value judgments?
Question 7 lies on the border between philosophy of science and epistemology (see sec. 2.8), and question 8 on the border with meta-ethics (see sec. 2.5, 2.10).
Beyond its fundamental significance, which consists in providing answers to the above questions, philosophy of science also has a number of significant applications, both inside and outside science.
The internal applications of philosophy of science consist of the supply of foundational knowledge, which aids the scientist's decisions concerning new or controversial questions. Internal applications also consist of working out interdisciplinary common ground and providing argumentative competence in critical reflection. Not least, philosophy of science has often paved the way for new scientific disciplines (such as probability theory and statistics, measurement theory, or parts of cognitive science).
Among the external applications of philosophy of science to problems in a societal context, two in particular should be emphasized:
aThe demarcation problem is highly significant in society. In this context, it consists of the question of which of our ideas have a claim to the status of objective scientific knowledge that should be taught in public educational institutions, as opposed to subjective opinion, political values, ideologies, or religious convictions. This question became politically explosive in the controversy surrounding the creationism movement in the USA. For example, Judge W. R. Overton in 1981 (McLean vs. Arkansas), and Judge Jones in 2005 (Kitzmiller vs. Dover) based their decisions against the teaching of creationism in school on demarcation criteria between science and religious belief proposed by philosophers of science (cf. Bird 1998, 2â9; Branch 2011, 174). To tell the full truth, there were also philosophers of science, such as Laudan (1983), who argued against the possibility of demarcating science from pseudo-science, and they have frequently been quoted by creationists as support for their position (to the embarrassment of other philosophers; cf. Pennock 2011, 176ff).
bEqually significant is the critical role of philosophy of science concerning the commercial and political utilization of science, which counteracts the danger of abusing science and its results. Politicians, the media and business leaders enjoy quoting expert opinions, which are presented all too often in a false or one-sided way in order to serve preordained purposes (sec. 2.10.1, 4.3.6â7, 4.4). But also applied scientists are often tempted to put subjective (e.g. financial) interests above objectivity. An example is the discovery of systematic biases in pharmaceutical research towards the financially supporting firms; philosophers of science have promoted scientific journal policies that may help to counteract such biases (Brown 2008).
1.2 On the Historical Development of Philosophy of Science
Although the term âphilosophy of scienceâ was only introduced in the 20th century, the philosophy of science is as old as science itself and had a parallel development (see Losee 2001). The history of the philosophy of science begins with Aristotle (384â322 bc), the ancient world's great systematizer of knowledge. Aristotle was much more oriented towards experience than was his teacher Plato. He was nevertheless, like most philosophers after him, a follower of the foundationalist epistemological program. In this epistemological program it is presumed that real knowledge is only possible if it stands on a foundation of certain and necessary principles, which are arrived at not through uncertain experience, but through rational intuition (cf. Triplett 1990, sec. I; Albert 1985, 18â28). Aristotle spoke in this context of âintuitive inductionâ (Losee 2001, sec. Ia). In current philosophy of science, by contrast, the fallibilist epistemological program has the upper hand, which concedes that our understanding of reality is basically fallible, and our scientific knowledge can be more or less well confirmed, but it cannot be guaranteed to be free of error.
Considerable advances in science and its philosophy had already been achieved by the late middle ages (Crombie 1959). Under the influence of philosophers such as Roger Bacon (1214â1292) or William von Ockham (1295â1349), the foundationalist program was gradually replaced by empirically oriented methodology. Of lasting importance is the principle of Ockham's razor, according to which one should reject all theoretical assumptions which are not needed to explain the observable. The decisive breakthrough, however, did not take place until the early modern period. Building on the great successes of scientific method in this historical periodâthanks to pioneers such as Galileo Galilei (1564â1642), Isaac Newton (1642â1727) and (later) Charles Darwin (1809â1882)âthe influential empiricist movement was established in the Philosophy, beginning with Francis Bacon (1561â1626) and John Locke (1632â1704) until David Hume (1711â1776) and John Stuart Mill (1806â1873). In the same period, the foundationalist epistemological program developed into the rationalist movement, prominently represented by RenĂ© Descartes (1596â1650), Gottfried W. Leibniz (1646â 1716) and Immanuel Kant (1724â1804).
The essential difference between the empiricist and rationalist philosophies can be characterized as follows. For the empiricists, sentences which may be justified a prioriâthat is, by pure reason and with rational certaintyâare limited to so-called analytical sentences, i.e. sentences whose truth is based on logic and conceptual convention. Such sentences possess no realistic content, they say nothing about the real worldâonly synthetic sentences can do this, but they can only be justified a posteriori, that is, based on experience. For the rationalists, on the other hand, a-priori justifiable sentences with realistic content do exist, namely the so-called synthetic a-priori sentences. However, both Descartesâ and Kant's attempts to justify synthetic a-priori principles of the sciences were unsuccessful and have been refuted by the further development of science. The development of the modern philosophy of science is closely bound with the insight that the foundationalist epistemological program was not tenableâat least not in its âstrongâ version as explained above.
For a long time, classical systems of philosophical empiricism too had reductionist and foundationalist tendencies. The skeptical consequences of empiricism, which called for epistemic humility, were first recognized and radically formulated by Hume. He showed that the two central tenets of scientific method, the causality principle and the induction principle, are neither logically nor empirically justifiable. The causality principle says that all regular successions between events are produced by causeâeffect relations; but Hume objected that all that one can observe are the successions of the events, while the idea that the earlier event or âcauseâ produces the later event as its âeffectâ is metaphysical fiction (see sec. 6.7.2). The induction principle asserts that regular connections between events that have been observed in the past will also hold in the future; but Hume argued that this inference can be justified neither by logic nor by experience (see sec. 2.11). The problems involved in the justification of the principles of induction and causality have occupied philosophers up to the present day.
The apparent insufficient justifiability of empiricism put wind in the sails of subsequent rationalist movements, in which the foundationalist epistemological program, however, was gradually given up, or replaced by pragmatized or historicized ârationalismsâ (see sec. 1.3.3â5). In the 20th century, post-empiricist and post-rationalist approaches have moved considerably closer to each other, and in the context of this tension, present-day philosophy of science has developed.
1.3 Philosophical Positions in Contemporary Philosophy of Science
1.3.1 Logical Empiricism
One of the most important origins of modern Philosophy of Science and Analytical Philosophy is logical empiricism, which was developed in particular by the Vienna circle, but also by others, for example by members of the Berlin circle around Hans Reichenbach (1891â1953). The Vienna circle was a group of philosophers and scientists in Vienna, whose core consisted of Moritz Schlick (1882â1936), Otto Neurath (1882â1945) and Rudolf Carnap (1891â1970). In the tradition of Ernst Mach (1838â1916), this group attempted to re-establish empiricism and scientific philosophy in general (cf. Stadler 2001). What was new about their situation was the development of modern logic, which had not been founded until the end of the 19th century. Modern logic made it possible to represent any language-based epistemological system with mathematical precision, and so the Vienna circle hoped they had found at last the methodological equipment for a philosophy which could progress in a scientific manner (cf. Schlick 1930/31, 155f). In the middle of the 1930s the Vienna circle, with political leanings from liberal to socialist, had to disband under pressure from the National Socialists. The majority of its members emigrated, some via other countries, to the USA, where the logical-empirical movement, uniting with related Anglo-American directions, developed into Analytical Philosophy, and gained a foothold in Europe in the post-war period.
What today's philosophy of science can learn from logical empiricism is not so much any particular thesis but, rather, the high standards of conceptual and argumentative precision. In the phase up to 1935, the philosophy of science of logical empiricism was restricted by positivism and reductionism. In the later phase, the logical empiricists gradually rejected their restricted positions and replaced them with theses, to which the designations âempiricismâ or âpositivismâ in the usual sense no longer apply. In one regard, logical empiricism has p...