From owner-bhaskar Sun Oct 6 18:00:47 1996
Date: Sun, 6 Oct 1996 15:56:01 -0600
Message-Id: <199610062156.PAA06481@marx.econ.utah.edu.econ.utah.edu>
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.
.