From owner-bhaskar Sun Oct 6 18:00:47 1996 Date: Sun, 6 Oct 1996 15:56:01 -0600 Message-Id: <> From: Hans Ehrbar <> Subject: rts2-15b (RTS2, end of Section 5 of Chapter 1, starting on p. 51) The world consists of things, not events. Most things are complex objects, in virtue of which they possess an ensemble of tendencies, liabilities and powers. It is by reference to the exercise of their tendencies, liabilities and powers that the phenomena of the world are explained. Such continuing activity is in turn referred back for explanation to the essential nature of things. On this conception of science it is concerned essentially with what kinds of things they are and with what they tend to do; it is only derivatively concerned with predicting what is actually going to happen. It is only rarely, and normally under conditions which are artificially produced and controlled, that scientists can do the latter. And, when they do, its significance lies precisely in the light that it casts on the enduring natures and ways of acting of independently existing and transfactually active things. There is nothing esoteric or mysterious about the concept of the generative mechanisms of nature, which provide the real basis of causal laws. For a generative mechanism is nothing other than a way of acting of a thing. It endures, and under 52 A Realist Theory of Science appropriate circumstances is exercised, as long as the properties that account for it persist. Laws then are neither empirical statements (statements about experiences) nor statements about events. Rather they are statements about the ways of acting of independently existing and transfactually active things. It is now possible to give a positive interpretation of our characterization in Section 3 of the objects of scientific investigation, at least in so far as they are causal laws, as `structured intransitive'. `Structured' in so far as it is the activities of mechanisms and causal structures, not the occurrence of events, that are designated in statements of causal law. `Intransitive' in so far as the mechanisms and causal structures, whose activity is designated, endure and act quite independently of men. To discover the independently existing and transfactually active machinery of nature is not, it should be stressed, the aim of an independent inquiry of metaphysics. Rather, it is the end to which all the empirical efforts of science are directed. Ontology has been vindicated not as providing a set of necessary truths about a mysterious underlying physical realm, but as providing a set of conditionally necessary truths about our ordinary world as investigated by science. It is important to be clear about what philosophical argument can achieve. Thus as a piece of philosophy we can say (given that science occurs) that some real things and generative mechanisms must exist (and act). But philosophical argument cannot establish which ones actually do; or, to put it the other way round, what the real mechanisms are. That is up to science to discover. That generative mechanisms must exist and sometimes act independently of men and that they must be irreducible to the patterns of events they generate is presupposed by the intelligibility of experimental activity. But is up to actual experiments to tell us what the mechanisms of nature are. Here, as elsewhere, it is the task of philosophy to analyse notions which in their substantive employment have only a syncategorematic use. Thus whenever a scientist refers to a thing or event, structure or law, or says that something exists or acts in a certain way he must refer to it under some particular description; he is using the notion of thing, law, existence, etc. But it is the task of the philosopher to analyse the concept as such. To argue that this task is both legitimate and necessary is not to populate the world with (or to suppose Philosophy and Scientific Realism 53 that there is a world of) things without names or events-in-general. I am now in a position to tidy up my analysis of experimental activity. The experimental scientist must perform two essential functions in an experiment. First, he must trigger the mechanism under study to ensure that it is active; and secondly, he must prevent any interference with the operation of the mechanism. These activities could be designated `experimental production' and `experimental control'. The former is necessary to ensure the satisfaction of the antecedent (or stimulus) conditions, the latter to ensure the realization of the consequent, i.e. that a closure has been obtained. But both involve changing or being prepared to change the `course of nature', i.e. the sequence of events that would otherwise have occurred.36 In a simple electrical experiment designed to illustrate say Ohm's Law, the wiring of an electric circuit and the generation of an electric current would constitute `experimental production'; maintaining the appropriate resistance levels, ensuring that no new magnetic field is suddenly placed in the neighbourhood of the circuit, etc. would then constitute `experimental control'. Only if the mechanism is active and the system in which it operates is closed can scientists in general record a unique relationship between the antecedent and consequent of a law-like statement. The aim of an experiment is to get a single mechanism going in isolation and record its effects. Outside a closed system these will normally be affected by the operations of other mechanisms, either of the same or of different kinds, too, so that no unique relationship between the variables or precise description of the mode of operation of the mechanism will be possible. In general, experimental activity requires a degree of plasticity of the antecedent (stimulus) and circumambient conditions to human manipulation and control. Such plasticity is not easily won. `Experimental design' is a substantial theoretical labour in itself. 36 Formally we could say that in experimental production by doing phi we change alpha to a so altering the state that would otherwise have prevailed; and in experimental production by doing or being prepared to do psi we exclude the intervention of elements beta_1 . . . beta_n, so allowing the mechanism M set in motion by a to generate b. The sequence a.b thus appears as a consequence of the results of our actions. It is in this sense that a closure is normally a human product. 54 A Realist Theory of Science It has often been said, metaphorically speaking, that in an experiment we put a question to nature. But it has not been said that the question we put is a practical one - with our hands, so to speak. The weakness of previous analyses of experimental activity is that they have not appreciated the significance of the fact that conjunctions of phenomena have to be worked for practically (as well as in thought); that conjunctions are not given to, but *made* by us. In an important study, von Wright has seen this. But he has not drawn the correct conclusion from it: which is that, just because the experimenter is a causal agent of the sequence of events, there must be an ontological distinction between the sequence he generates and the causal law it enables him to identify. Any other conclusion renders experimental activity pointless. (Why generate that sequence?) The reason for von Wright's failure to see this stems from his unfortunate initial assumption of (as he puts it) a `Tractatus-world', i.e. a world of logically independent atomistic states of affairs (which astonishingly he seems to regard as a harmless simplification);37 which precludes him from seeing laws as anything other than conditional statements about atomistic states of affairs. It is of course something of a scandal that empiricists who invoke experience as the sole ground of knowledge and scientific knowledge as their paradigm should not have undertaken an analysis of the conditions under which experience is significant in science. It should be stressed that the result that there is an ontological distinction between causal laws and patterns of events depends upon only two premises: (i) that men are causal agents capable of interfering with the course of nature and (ii) that experimental activity, the planned disruption of the course of nature, is a significant feature of science. In stressing the practical component of experimental activity, it is important not to forget the theoretical side. In an experiment men put a question to nature. But they must put it in a language that nature understands, as well as in a form that makes possible an unambiguous reply. It is difficult to overestimate the importance for modern science of the development of instruments such as clocks and telescopes, which may be seen as devices designed to decipher the vocabulary of nature. Both the 37 See G. H. von Wright, op. cit., pp. 43-45. Philosophy and Scientific Realism 55 construction and the interpretation of such instruments depended upon theory. Hooke's law, for example, is literally built into the construction of spring balances.38 Experimental confirmation of Galilean dynamics was delayed for a long time by the difficulty of measuring `the most fundamental magnitude of dynamics', i.e. time. But when the Huyghens eventually succeeded in building such a clock in 1659 it was only by basing it on the new dynamics (the very dynamics it was designed to vindicate) and in particular the theory of the isochronous curve of the pendulum.39 Similarly it has been convincingly argued that the development of cosmology in the early 17th century was held up by the absence of an adequate theory of telescopic vision.40 In short, experimental activity depends crucially upon the adequacy of the theories (sometimes referred to as `auxiliary') according to which the experimental equipment is constructed and its results interpreted. Two problems are raised by my analysis of experimental activity. First, we know that much science, of what might be called a fundamental kind, has proceeded by way of `thought' rather than by actual experiment. As Dijksterhuis has put it: `In general one has to take stories about experiments by Galileo, as well as his opponents with some reserve. As a rule they were performed mentally, or they are merely described as possibilities.'41 It seems that Einstein too was not averse to the occasional `Gedankexperimente'.42 This raises the question of whether, and if so how, pure thought can anticipate a law? And the problem of how, if it can, we then avoid the rationalist conclusion that provided only our anxiom base is strong enough we could deduce all the laws of nature without recourse to experience. Secondly, we know that in many fields, most notably history and the human sciences and in the biological sciences in aspects of their work, experimental activity is impossible. This raises the question of whether there are, or it is possible to devise for them, surrogates of the experimental establishment of 38 Cf. N. R. Hanson, Observation and Explanation, p. 56. 39 See e.g. A. Koyre, Metaphysics and Measurement, Chap. 4. 40 V. Ronchi, `Complexities, advances and misconceptions in the development of the science of vision: what is being discovered ?', Scientific Change, ed. A. Crombie, pp. 542-61. 41 E. J. Dijksterhuis, The Mechanisation of the World Picture, p. 338. 42 See K. R. Popper, The Logic of Scientific Discovery, App. XI. 56 A Realist Theory of Science closed systems in physics and chemistry? And here again there lurks an unacceptable rationalist implication. Both pose prima facie problems for transcendental realism, which I hope to be able to resolve at a later stage in this study. .