MARCO TEÓRICO
2. Aculturación e identidad étnica en la adolescencia
2.2. Identidad étnica
2.2.3. Desarrollo e identidad étnica
It is a central task of the philosophy of science to give an account of scientific concept and theory formation. Following the successful work in metamathematics (Gottlob Frege, David Hilbert), philosophers at the turn of the twentieth century started to apply the tools of modern logic to the study of the language of science and the structure of scientific laws and theories.1
The positivist school accepted the empiricist view that concepts are learned from experience. They attempted to show that science uses an ‘empirical’ or ‘observational’
language, and all meaningful concepts are reducible to this language. More precisely, the observational language L
0 contains, besides logical vocabulary, only observational terms (individual constants, one-place and many-place predicates O 1 , . . . , O m
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). These terms are directly connected to the empirical world through sense perception,
measurement, or ‘operational definitions’. All other terms are explicitly
definable by the observational language. The full language of science L, which contains also theoretical terms M 1 , . . . , M k (like ‘electron’, ‘force’, ‘energy’, ‘temperature’,
‘gene’), is in this sense reducible or translatable to the observational language L 0
On this descriptive view of theories, a scientific theory is simply a set of sentences T in the language L. As advanced theories are formulated in axiomatic form, T is the set of logical consequences of a set of axioms A. Thus, T itself is closed under deduction. As Ernst Mach put it, the main task of a theory is to give an ‘economical’ description of the phenomena (see Fig. 12).
.
The logical empiricists of the Vienna Circle developed two formulations of descriptivism.
The phenomenalists took the empirical world to consist of sensations and their complexes; hence, the observational language L 0
The rationalist and Kantian traditions regard concepts either as innate elements or as free creations of the human mind. Concepts are like nets that we throw out to the world. As
contains phenomenal terms referring to subjective experiences. For the physicalists, the world consists of publicly observable things and properties; the observational language in this case is an empirically interpreted physical language. Both views can accommodate the descriptive conception of theories, as Rudolf Carnap's work in 1926–35 shows.
Mach himself and the French conventionalists (Henri Poincaré, Pierre Duhem) noted, such concepts are often idealized and do not as such correspond to anything in the world.
If this
Fig. 12. Descriptive View Of Theories
view is combined with the assumption that reality (or at least the reality accessible to science) equals the empirical world, the position known as instrumentalism is obtained (cf. Section 1.3).
The instrumentalists typically assume with the descriptivists that the language of science contains the observational part L 0 , but they also admit the use of ‘auxiliary’ theoretical terms which are not reducible to L 0
Besides systematic natural sciences, instrumentalism has been defended also in the case of history. For example, Franklin Ankersmit (1989) claims that historical concepts like
‘the Renaissance’ do not ‘refer to historical reality itself’ but to narrative interpretations of the past. As the past ‘can no longer be observed’, it ‘cannot be the proper object of investigation’. The historian's task is to construct a narratio or a coherent historical story on the basis of the traces that the past has left, but it is not ‘meaningful’
via definitions. These auxiliary terms are understood as tools or instruments for the purpose of systematizing observational statements (thereby making theories more simple or economical) or for making observable predictions (see Fig. 13). These linguistic or symbolic tools are given no interpretation, i.e. they are not taken to be referring to anything, and the statements including them lack a truth value.
This semantical claim as such leaves open the ontological question of whether anything beyond the observable exists. An instrumentalist may be agnostic concerning the
existence of theoretical entities (like atoms, electrons, forces, black holes, neuroses), but usually they are treated as at best useful fictions.
Fig. 13. Instrumentalism end p.111
to speak about a correspondence of the narratio and the actual past. In other words, Ankersmit has the same attitude towards events in the past as an instrumentalist has to unobservable theoretical entities.
Carnap's seminal article ‘Testability and Meaning’ (1936–7) proved convincingly that dispositional terms (like ‘magnetic’, ‘fragile’, ‘jealous’) are not explicitly definable by observational terms. Within the analytic philosophy of science, this argument led to the Received View of theories as ‘partially interpreted’ sets of statements. According to the two-layer account, the uninterpreted ‘pure theory’ is connected to the observational part via ‘bridge principles’ or ‘correspondence rules’, which may have any logical form (instead of explicit definitions), and the observational terms are then linked with the empirical reality (see Fig. 14). Here the observational terms are taken to be completely interpreted, i.e. their extension in the world is fixed, but this does not uniquely fix the extensions of the theoretical terms, which thus remain only partially interpreted.
The Received View is still open to the instrumentalist interpretation, since the bridge principles need not guarantee that theoretical statements have a truth value. Carnap hesitated about this question, while Herbert Feigl (1950) defended the realist view that theoretical terms are meaningful by their reference to unobservable entities.
Fig. 14. The Received View end p.112
Carl G. Hempel (1958) raised this issue in his Theoretician's Dilemma: if the theoretical terms of a theory T achieve deductive systematization among observational statements, then the same systematization is achieved by an observational subtheory T c of T in the observational language L 0
One way of constructing the theory T
(as shown by a logical result of Craig). If the theoretical terms are dispensable in this sense, the argument continues, there can hardly be any reason to assume that they are cognitively significant referring terms.
c , which has the same deductive consequences as T itself in L 0 , was discovered by Frank Ramsey in 1929. Replace the theoretical
predicates ‘M 1 ′, ‘M 2 ′, . . . , ‘M k ′ of T by predicate variables ‘w 1 ′, ‘w 2 ′, . . . , ‘w k ′, and quantify them existentially. The resulting second-order statement TR
• (1)
•
is known as the Ramsey sentence of theory T. However, it is not clear that Ramsey's approach really supports instrumentalism or fictionalism, since TR asserts the existence of some entities corresponding to the original theoretical terms M 1 , . . . , M k , and there is no guarantee that these entities are observable. Carnap was willing to allow them to be purely mathematical constructions (cf. Carnap 1966), but Feigl (1950) argued that the entities satisfying (1) should be restricted to classes defined by physical properties (cf.
Hempel 1965).
Later discussion about the Theoretician's Dilemma has not given support to
instrumentalism. It has been shown in detail that the introduction of new theoretical terms gives important methodological gains in deductive systematization (Tuomela 1973). As Hempel himself expected, theoretical terms are logically indispensable to inductive systematization: there are theories T and observational statements e and h such that h is inducible from e and T (or from e relative to T) but h is not inducible from e and the Craigian reduction of T (see Niiniluoto and Tuomela 1973).
As an alternative to descriptivism and instrumentalism, the thesis of theoretical realism asserts that all scientific statements in scientific theories have a truth value (see thesis (R2) in Section 1.3). A scientific realist takes theories seriously as attempted descriptions and explanations of reality. A theory may go beyond the edge of direct observability by postulating theoretical entities, if it yields predictions testable by public observation. For this conception, as Sellars (1963) argues convincingly, it is crucial to distinguish between the semantic relations of the theory to the reality it tries to describe and the
methodological relations of the theory to the observational processes used for testing the theory (see Fig. 15). For example, quantum mechanics is a theory about the micro-world of end p.113
Fig. 15. Scientific Realism
elementary particles, not about observations and measurements in laboratories (cf.
Section 5.4). A psychological theory of consciousness is about mental processes, not
about their manifestation in behaviour (cf. Section 5.4). A historical narrative is about events in the past, not about their traces and documents existing today.
Fig. 15 does not yet say anything about the question whether the theory is good as a description or representation, i.e. successful in terms of reference or truth. These questions have to be studied separately (see Section 5.2 and Ch. 6).
We have already prepared the ground for this realist interpretation of theories. It makes sense to speak about mind-independent reality (Ch. 2) and about semantic non-epistemic relations between statements and reality (Ch. 3). The truth value of a theory is
independent of epistemic issues—the testing process does not influence this truth value, but only our rational estimates of this truth value (Section 4.5).
I have here construed instrumentalism as a position which accepts the correspondence theory of truth, but claims that this concept is not applicable to theoretical statements (cf.
Section 1.3). Semantical anti-realists, who advocate an epistemic concept of truth and a restricted notion of reality, are not instrumentalists in this sense, but they could be
‘instrumentalists’
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in John Dewey's (1938) sense: theories (like language in general) are a tool of prediction, so that this view of theories would resemble Fig. 13 rather than Fig. 15. Related views are supported, for instance, by Chalmers (1976) and some ‘practical materialists’ in the Marxist school. But there are also philosophers who wish to combine theoretical realism with an epistemic notion of truth. These epistemic scientific realists basically accept the picture in Fig. 15, but analyse the theory–world relation by some other concept than truth—e.g. by Sellars's notion of ‘picturing’ (see Sellars 1968; Tuomela 1985; cf.
Brandom 1994, however).
Scientific realism is also in conflict with the anti-representationalist view of language that Richard Rorty defends by appealing to Donald Davidson. Rorty urges that the realism vs. anti-realism issue arises only for those representationalists who take language to be a better or worse representation of the world (Rorty 1991: 2). He admits that the use of the word ‘atom’ in physics is ‘useful for coping with the environment’, but this utility should not be explained by notions like representation (ibid. 5; cf. Rorty 1998). Here we can see that Rorty's anti-representationalism in fact combines ideas of instrumentalism in both senses discussed above.
It is essential to theoretical realism that it is meaningful to speak about ontologically mind-independent reality—this minimum assumption is the ‘fig-leaf realism’ of Devitt (1991). When Ernest Nagel (1961) suggested that, given the ambiguity in the term
‘reality’, the whole opposition between realism and instrumentalism is merely ‘a conflict over preferred modes of speech’ (p. 152), he was relying on the idea that reality could be defined as ‘that which is invariant under some stipulated set of transformations’ (p. 149) (see also Carnap 1966). This argument is not convincing. The conception of reality as a hierarchy of more and more general and deep phenomenal invariances was developed by Kaila in the 1930s (cf. Section 4.2 and Kaila 1979), but he combined it with the
translatability thesis from theoretical to observational language. This approach leads neither to instrumentalism nor to realism but rather to the descriptive view of theories.
When Kaila eventually gave up the translatability thesis in the late 1940s, his position
became clearly a realist one: the physical reality described by theories is different from the phenomenal domain in Fig. 15 (see Niiniluoto 1992a).
The realist view of theories gained indirect support from the collapse of the
observational–theoretical dichotomy, which is a common premiss of descriptivism and instrumentalism. Following Wittgenstein, N. R. Hanson () argued that all seeing is seeing as. Thomas Kuhn () and Paul Feyerabend () argued that observations are theory-laden, relative to variable conceptual-theoretical frameworks. (At this stage of his career, Feyerabend was still a scientific realist.) This basically Kantian epistemological viewpoint undermines strict or naive versions of empiricism, and it was used by sophisticated critical realists to support the picture of Fig. 15 (cf. Tuomela 1973).
There are various pragmatic, context-dependent ways of dividing scientific terms into two classes: old vs. new, antecedently understood vs. not yet understood, measurable vs.
non-measurable by available instruments, measurable-relative-to-theory-T vs. not-T-measurable, etc. But there do not seem to be any convincing grounds for a semantic division such that on one side the statements have a truth value and on the other side they lack a truth value. If this is the case, then the basic premiss of instrumentalism fails.
The theory-ladenness of observations leads, however, to other arguments which challenge scientific realism. These issues will be discussed in the next section.
I conclude this section by remarks on three important views that have been regarded as contemporary heirs of instrumentalism.
Bas van Fraassen's (1980; 1989) constructive empiricism differs from instrumentalism, since he admits that theories have a truth value.2
A realist of course agrees that empirical adequacy is a desirable property: the
observational consequences of a theory should be true—or at least approximately true.
But as soon as van Fraassen admits that theories have a truth value, it becomes
problematic to claim that the truth ‘about the observable’ is the only relevant feature of acceptable theories. If a theory saves the phenomena by making false theoretical postulations or
His emphasis on the importance of explanation also differs from the descriptivist Mach–Duhem tradition. However, van Fraassen urges that the truth value of a theory is irrelevant to the aims of science. Using a slogan which links him to the ancient instrumentalist programme, he demands that a theory should ‘save the appearances’. Constructive empiricism requires, instead of truth, that a theory is ‘empirically adequate’: what the theory says about ‘the observable’ is true. The acceptance of a theory involves only the claim that it is empirically adequate, not its truth. This requirement is illustrated in Fig. 16: theory is true in a model, and the observable is isomorphically embeddable in this model. (Such partial truth about observational substructure is called ‘pragmatic truth’ by Mikenberg, da Costa, and Chuaqui 1986.)
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Fig. 16. Constructive Empiricism
constructions (in the white area of the model in Fig. 16), is this as good as saving the same phenomena by a true or truthlike theory?
Van Fraassen would regard the realist's intervention as question-begging. His reply is theoretical scepticism: the truth of theories should not be required, since we do not have any knowledge about the unobservable. He supports this view with the thesis that theory is underdetermined by evidence (cf. Section 6.3) and with an attack on abduction or inference to the best explanation (van Fraassen 1989) (cf. Section 6.4).
As many realist critics have pointed out, van Fraassen's position presupposes here that there is an important observational–theoretical distinction. Van Fraassen himself admits that this distinction is not unique, but depends on our theories. For his epistemological purposes, he requires that the former category includes only observability by unaided human senses, but for a fallibilist this seems clearly unsatisfactory: even naked observation reports are uncertain to some degree, and their epistemic status does not sharply differ from measurement results by scientific instruments (or from indirectly testable theoretical hypotheses). It should also be noted that van Fraassen construes his opposition to the form of realism
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which takes theories to be ‘literally true’ stories (van Fraassen 1980: 8), instead of critical realism, and this at least weakens the force of his arguments for constructive empiricism.
Van Fraassen is one of the pioneers of the so-called semantic view of theories. For many purposes, philosophers have invented methods of replacing sentences (whose syntactical formulation is always somewhat arbitrary) by propositions. One proposal is to identify a proposition with the class of models of a sentence (in the sense of model theory) or with the class of possible worlds where it is true (see Section 3.3). Where the statement view of theories takes a theory T to be a set of sentences, the semantic view replaces T with the class Mod(T) of the models of T. According to the formulation of Patrick Suppes, who applied this idea to mathematical and physical theories, to define a theory is to define a class of structures by means of a set-theoretical predicate (e.g. ‘is a group’, ‘is a
Newtonian system’).3
In the statement view, a theory T is intended to be true in the actual world M
*
• (2)
. The claim of those of who advocate the theory is thus
•
i.e. T is true in M*
• (3)
. The model-theoretic counterpart of (2) is
•
i.e. M*
The structuralist school (Joseph Sneed, Wolfgang Stegmüller, Carlos Ulises Moulines, Wolfgang Balzer) develops this basic idea by defining a theory directly as a set of structures M, and thereby eliminating (talk about) the language of the theory.
is a model of T.
4
• (4)
Further, they define the set I of the intended applications of the theory: I is the historically changing domain of situations where the supporters of the theory think the theory to be applicable. For example, the initial set I for Newton's theory included planets, freely falling bodies, projectiles, and pendulums—and later, when the theory developed, rigid bodies, temperature, etc. In other words, instead of thinking the theory to have one global application (i.e. the actual world), the theory is taken to have several, possibly
overlapping applications. The claim of the theory is then, instead of (3),
•
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I think these ideas are important and useful. They are not incompatible with the statement view, since at least in most typical cases a class of structures M can be defined by sets of sentences in languages with sufficiently rich vocabulary and logic, i.e. M=Mod(T) for some T (cf. Niiniluoto 1984: ch. 6; Pearce 1987a). They can be understood in the realist sense, since (4) then requires the theory T to be true in all intended applications in set I.
This also suggests that the truthlikeness of a theory T should primarily be evaluated
relative to each intended application M in I. For example, instead of asking what the degree of truthlikeness of Einstein's Special Relativity Theory is, we should study
separately its accuracy for cosmological models, planets, satellites, etc. (cf. Gähde 1997).
If a global measure of the truthlikeness of a theory T is needed, it should be a weighted sum of the degrees Tr(T, M) for the intended applications M in I (cf. Niiniluoto 1987a:
370–1).
However, the structuralist approach has received an instrumentalist flavour from Sneed's theory-relative distinction between T-theoretical and T-non-theoretical terms, and the Ramseyan reformulation of the claim (4). According to Sneed, the intended applications I of a theory T are T-non-theoretical, and the ‘empirical claim’ of T asserts that