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Ancient Greece witnessed profound developments in the mathematical sciences, most notably geometry, associated with the names of Eudoxus, Euclid, Archimedes, and Apollonius. In planetary astronomy, a sophisticated and (almost) empirically adequate earth-centred account was given by Ptolemy. Important work was also done in biology (Aristotle, Theophrastus) and in physiology and medicine (Hippocrates, Galen). From a modern point of view, the glaring weakness of ancient science was its conception of motion, divided by Aristotle into terrestrial (rectilinear) versus celestial (circular) and into ‘natural’ (goal-directed) and ‘forced’ (requiring the continuous action of an external force).
The Middle Ages inherited from Aristotle a picture of the cosmos as a finite, earth-centred, hierarchically organised plenum. Since Aristotle’s texts (the Physics, On the Heavens) set the syllabus, his arguments were exhaustively and critically analysed by scholastic philosophers such as Jean Buridan and Nicolas Oresme. Aristotle’s conception of ‘forced’ motion as requiring the continuous operation of an external mover proved very difficult to reconcile with the motion of projectiles. In place of Aristotle’s own theory of the medium (eg the air) serving the role of the external mover, Buridan and Oresme proposed that the hand impart an ‘impetus’ to the stone, which impetus then sustains its motion. This medieval theory of impetus is (in some versions) empirically equivalent to the modern theory of inertia, although conceptually they remain poles apart. The medieval critique of Aristotle’s views on space, motion, and motive force proved liberating to the new ideas of Nature emerging in the Renaissance, e.g. to the Copernican Revolution in astronomy and to the re-emergence of Atomism as a theory of matter.
Nicolas Copernicus' heliocentric model of the Universe signalled the beginning of the end for the Aristotelian cosmology. Although Copernicus' model was in all other respects perfectly compatible with the Aristotelian system (it could, for instance, accommodate the crystaline spheres), the model precipitated a succession of changes and additions (mainly by Tycho Brahe, Galileo Galilei, and Johannes Kepler) that eventually did away with the Aristotelian view altogether. This fundamental change in cosmology was accompanied by similarly profound changes in physics and in scientific methodology in general.
Many important episodes in the modern history of science have captured philosophers' interest. The following four figure prominently amongst the case studies most often discussed by philosophers, epistemologists and methodologists of science.
What happens when a substance burns? The emission of heat and light suggests to the naive observer that the burning substance is emitting something into the atmosphere. From this common-sense observation it is but a short step to the theory that all combustible substances contain a common material principle, phlogiston, whose presence explains that property. In combustion, according to the phlogiston theory, a non-metal like sulphur or phosphorous loses its phlogiston to the air, releasing the corresponding acid. Likewise in the calcination of metals, the shiny metal gives up its phlogiston, leaving the powdery calx (which we call an oxide). The phlogistic theory provided a successful research programme for eighteenth-century chemistry, but faced a number of troubling anomalies. If a metal releases phlogiston during calcination, why does the calx weigh more than the metal? If addition of phlogiston is necessary for metallic reduction, how is it that mercury ores can be reduced without addition of a ‘phlogistic’ material such as charcoal? These problems led phlogiston-theorists to propose modifications to their basic theory, but each new modification brought further difficulties and complexities. The crucial step was taken by Lavoisier, who argued in his famous Reflexions sur le Phlogistique that phlogiston does not exist at all, and that combustion involves the decomposition, by the combustible substance, of oxygen gas, with its ponderable component combining with the combustible to form an acid (for non-metals) or a basic oxide (for metals), and its imponderable ‘caloric’ supplying the light and heat of combustion. This overturns the whole theory of composition: what is simple for the phlogistonist is complex for Lavoisier, and vice versa. In Thomas Kuhn’s Structure of Scientific Revolutions, this revolution in chemistry provides one of the chief examples, but whether the historical episode does or does not fit Kuhn’s model continues to divide historians and philosophers of science.
Theories of evolution were commonplace in the nineteenth century, and existed in a number of versions before Darwin. What was revolutionary in Darwin’s theory was his austerely reductive account of how evolution occured. From three simple and seemingly undeniable premises (heredity, variation, and the struggle for existence) he deduced the existence of natural selection. Given enough time, he argued in the Origin of Species (1859) natural selection can account not only for the marvellous adaptation of existing plants and animals to their respective environments, but also for the emergence of entirely new forms. The whole process is ‘blind’ and purposeless: the theory requires neither a transcendent designer (God) nor a sort of immanent striving towards ‘higher’ forms. This made Darwin’s theory extremely unpopular, not just with the defenders of Christian orthodoxy but also with most of the natural philosophers of the period. The structure of the ‘Darwinian Revolution’ is of importance to philosophers of science not just for its own sake, but as a test-case for rival accounts of revolutions in science. It is also of interest for attempts to distinguish positive science from ideology. Given the multiple uses (or abuses) of Darwinism for ideological purposes in the last century, are we any nearer to separating out a core of ‘positive science’ from all the ideological baggage that has been imposed on it?
In 1905, Einstein published his famous paper on relativity. This paper was to dramatically change our understanding of the notion of time. Einstein followed this up with a number of studies into the nature of space and time, studies that essentially linked the phenomenon of gravitational attraction to the geometry of space and time. What exactly are the philosophical and methodological implications of Einstein's Special and General Theories of Relativity? What are the sources of Einstein's insights: experimental or theoretical? In what way was Einstein's Special Theory of Relativity superior to its competitors, notably the sophisticated theory of length-contraction and time-dilation due to Lorentz? And why was Einstein's theory in the first instance received much more enthusiastically in the Continent than in Great Britain?
The structure of quantum mechanics is full of interesting philosophical puzzles: questions concerning its interpretation are still alive and very much with us. The history of the discipline also raises a very large number of interesting methodological issues, such as the role of historical contingency in the acceptance of physics theories, the relation of ad hoc assumptions and empirical adequacy. Other conceptual issues concerning causality, determinism, and the domain of the physical theory are clarified when framed in the historical terms of the debates between the founders of quantum mechanics, such as Planck, Einstein, Bohr, Heisenberg, Jordan, Pauli and Dirac. And the emergence of this revolutionary theory is fascinating in its own right.
Traditionally historians and sociologists of science have been preoccupied mainly with an understanding of the social, political and institutional evolution of science. In other words, they were concerned with the process of science, rather than the actual product, and assumed that the content of scientific knowledge was beyond their domain of study. This understanding of the role of social history of science was reinforced by (nowadays discredited) philosophical theories that aimed to distinguish the context of discovery from the context of justification (see Philosophy of Science). However, the area of science studies has recently undergone a revolution in their own right. Present-day social historians claim that the content of scientific knowledge is as much part of their scholarly domain as the social setting of the scientific activity. In order to distinguish their new form of scholarship from traditional sociology of science, they have baptised their discipline "the sociology of scientific knowledge" (SSK).
Traditional sociology of science finds its inspiration and most sophisticated formulation in the works of Robert K. Merton. Against this background, a number of sociologists of science working at Edinburgh University in the 1970s developed the Strong Programme in the sociology of knowledge. This programme is best characterised by means of David Bloor's four main principles (causality, impartiality, symmetry, reflexivity) explicitly designed to permit a socio-historical study of the content of scientific knowledge. (More recently Bloor and others have linked the Strong Programme to Wittgenstein's late philosophy.) The most exhaustive application of the Strong Programme is Steven Shapin and Simon Schaeffer's celebrated Leviathan and the Air Pump, a book that set the mechanical philosophy of Robert Boyle in its social an historical milleau, and drew important connections between Boyle's science and Hobbes' politics. Another milestone was Andrew Pickering's Constructing Quarks.
More recently, several science studies scholars have tried to leave the Strong Programme behind. Bruno Latour, for instance, has argued that the distinction between social and natural factors in scientific belief presupposed by the Strong Programme is neither sound, nor appropriate for understanding science. Instead Latour's actant theory advocates an ontology of intentional objects, or quasi-objects. By contrast, Andrew Pickering, once one the leading advocates of the Strong Programme, has recently called for a robust materialism, coupled with a pragmatic realism, to replace the Strong Programme's talk of social interests. Bloor's recent polemical reply to Latour strongly suggests that the Strong Programme is closer to Pickering's views. The exchanges between these three eminent authors are philosophically sophisticated, and of great interest to philosophers and historians of science. Also of notable interest are the positive contributions to the debate by Ian Hacking and Arthur Fine, two very distinguished contemporary philosophers of science.