Journal of Philosophy, Inc.

Experiment and Theory: Constitution and RealityAuthor(s): Patrick A. HeelanReviewed work(s):Source: The Journal of Philosophy, Vol. 85, No. 10, Eighty-Fifth Annual Meeting AmericanPhilosophical Association, Eastern Division (Oct., 1988), pp. 515-524Published by: Journal of Philosophy, Inc.Stable URL: http://www.jstor.org/stable/2026810 .Accessed: 08/02/2012 13:59

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PHILOSOPHICAL SIGNIFICANCE OF EXPERIMENTATION 515

EXPERIMENT AND THEORY: CONSTITUTION AND REALITY*

H OW in a constitutional analysis do theories relate to experi- mental phenomena, and how do both relate to nature or reality: this is the theme of my paper. Examples are taken

chiefly from physics, e.g., Robert Milliken's oil-drop experiment and recent experiments in fundamental particles physics.'

The activities of scientific research all contribute to one or other of two distinct research strategies, experimental and theoretical. In this paper, we ask two questions: (1) How are the objects-for-knowing generated by experimental strategies related to the objects-for- knowing generated by theoretical strategies? (2) Which counts for reality?

The method I employ is constitutional analysis.2 This supposes that objects-experimental or theoretical-are prepared by the noetic activity of subjects in anticipation of being presented as ob- jects-for-knowing. Experimental and theoretical noetic activity are as different as looking at the sun and looking at the sunbeam-one can only do one at a time, for, though related, they are different noetic activities.

The function of theory is to explain via a mathematical model how and why the practical procedures work for the experimenter, whereas the function of experiment is to authenticate the presence of the phenomenon in the practical procedures. I take 'theory' to mean the mathematical model closest to experimental praxis (Hack- ing, 216-218; Galison, 249-254).

* To be presented in an APA symposium on The Philosophical Significance of Experimentation, December 28, 1988. Ian Hacking will be co-symposiast, and Peter Galison will comment; see this JOURNAL, this issue, 507-514 and 525-527, respec- tively, for their contributions.

' I am deeply indebted to many important studies by Harry Collins, G. Holton, B. Latour, Andy Pickering, Trevor Pinch, Steven Shapin, and others, of the historical, sociological, and psychological relationships between theory and experiment. Two deserve special mention: Peter Galison, How Experiments End (Chicago: Univer- sity Press, 1987); and Robert Crease, The Second Creation (New York: Macmillan, 1986). In the philosophical literature, I refer especially to Ian Hacking, Represent- ing and Intervening (New York: Cambridge, 1983); and Robert Ackermann, Data, Instruments, and Theory (Princeton: University Press, 1985); and my Space-Per- ception and the Philosophy of Science (Berkeley: California UP, 1983); but impor- tant work has also been done by others. [References in the text to these works are given in the form: (author, page numbers).]

2 Semantic analysis studies meanings, whereas constitution analysis studies the origins of meanings. For an account of constitution analysis, see, for instance, Robert Sokolowski, The Formation of Husserl's Concept of Constitution (The Hague: Nijhoff, 1964).

0022-362X/88/8510/0515$01.00 ? 1988 The Journal of Philosophy, Inc.

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Before plunging into constitutional analysis, let me present my conclusions in a preliminary way under the form of an analogy: a theory is related to a phenomenon as a musical score is related to a musical performance. Theory alone can no more witness to the au- thentic presence of a phenomenon than can the score alone of a piece of music witness to the authentic presence of a musical perfor- mance: there are hosts of other relevant factors in each case. The phenomenon and the musical performance are each the realization of theoretical models or schemata that depend on social, practical, technological, hermeneutical, and artistic judgments that are local, contextual, and immersed in cultural history.

HUSSERL'S TRANSFORMATION THEORY OF THE PHENOMENON The roots of constitution analysis are in Kant, Hegel, and Husserl. Husserl was trained in mathematics and taught at Gottingen (1901- 1916) during its "Golden Years." He was a colleague and friend of the great geometers, logicians, and axiomatizers who set the agenda for twentieth-century physics.3

Husserl applied Felix Klein's transformation theory of projective geometry to the analysis of perceptual objects. Just as a geometrical object lies somewhere between the subjectivity of the coordinate system and the objectivity of its representation in that system, so the perceptual object lies somewhere between the subjectivity of an indi- vidual viewing and the objectivity of the view that the individual gets. The geometrical object, for Klein, is the symmetry or invariant pre- served under permissible transformations of the representation and of the coordinate system; the perceptual object, for Husserl, is the symmetry or invariant preserved under permissible transformations of the viewing system and of the viewers. The key to the analysis is, of course, to identify correctly the transformation group (or symmetry group) of the phenomenon, i.e., the group of transformations that permute the profiles among themselves while preserving the stability of the phenomenon.4

Whereas most theoretical physicists have directed their research toward simplicity defined in terms of the symmetries of a model, most experimental physicists have directed their research toward a comparable experimental symmetry, the stable synthesis of a scien-

' Husserl was himself an axiomatizer-in anticipation of Patrick Suppes? Well, yes and no. See my "Husserl's Later Philosophy of Science," Philosophy of Science, LIv, 3 (1987): 368-390, for a commentary on Husserl's philosophy of science and a critique of it.

4 The importance of symmetries or invariance under transformation groups is borne out by high-energy physics. As Steven Weinberg says, "The Universe is an enormous direct product of representations of symmetry groups. It's hard to say it any more strongly than that" (Crease, 187).

PHILOSOPHICAL SIGNIFICANCE OF EXPERIMENTATION 517

tific phenomenon. Although the centrality of the model is stressed by all who take their inspiration from G6ttingen, the importance of a robust and stable phenomenon is, in the long run, more important. Both Ian Hacking and Peter Galison make a move in this direction (Hacking, 222, 229; Galison, 259-260).

The notion of view, profile, or perspective, however, involves a relation between perceiver and perceived. Every transformation af- fecting the object is paired with a correlative inverse transformation affecting the subject which would have the same phenomenological outcome. This second group of transformations, initiated by the agency of the subject, has the structure of the inverse group, but this has the same structure as the group itself, since every inverse trans- formation is also a member of the group.5

The correlativity of the objective and subjective transformation groups is in turn the key to understanding the constitution of the phenomenon. The objective transformation group is then the law of the objective constitution of the phenomenon. Husserl called it the noema of the phenomenon (cf. Heelan, 6-8). The subjective trans- formation group is the acquired ability of the prepared experi- menter to explore at will the noema of an object, and this is (what Husserl calls) noesis. Noesis is the law of subjective constitution of the object. One is led in this way into the analysis of perception as an active process and as a species of experimental performance. Noesis and noema then are correlative and (since a group and its inverse are the same) both are representations of the same basic transforma- tion group.

Constitutional analysis attempts (1) to define this basic transfor- mation group, and (2) to describe its noematic and noetic imple- mentations. These noetic implementations always employ the human body and its sensory systems; they may, in addition, involve technolo- gies such as instruments and the laboratory traditions that use them.

SCIENTIFIC PHENOMENA AS PERCEPTUAL OBJECTS

Can experimental phenomena be or become perceptual objects in the Husserlian sense? The answer depends on whether an experi-

5 In physics, the first group is called the active group, and the second-for constitutional analysis more interesting-group is called the passive group. Physi- cists call it the "passive" group because it seems to them that the passive group leads merely to redescriptions of the phenomenon. Husserl would have pointed out that observers are not passive spectators, that the phenomenon itself subsists between perceivers and profiles, and that, as a consequence, a constitutional analysis of the perceptual kind of a thing begins precisely with a study of "the passive transforma- tion group." For the notion of passive and active transformation groups in physics, see Eugene Wigner, Symmetries and Reflection (Bloomington: Indiana UP, 1957), p. 45.

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mental phenomenon can be prepared in a stable way by standard instrumental procedures so as to exhibit its symmetry structure. If it can, then it is a perceptual object in a world in which the equipment and laboratory skills for constituting such phenomena experimen- tally is available. I believe such a description applies to such things as electrons, positrons, muons, and possibly neutral currents and quark combinations, insofar as all of these can be constituted within tradi- tions of laboratory practice and presented as stable phenomena. (Cf. the discussions of muons in Galison, 126-133, and the general dis- cussion on pp. 252-262).

THE EXPERIMENTAL ROLE AND THE THEORETICAL ROLE O is the object-for-knowing constituted by the experimental role (S.), say, Milliken's discretely charged oil droplets. M is the set of instru- ments used in the preparation-presentation process. I use Dirac no- tation IX>. to represent the experimental profiles of the phenome- non 0, because I do not want to imply that 0 is a classically objective space-time object, that is, I want to make room for the possibility that not all of its experimental profiles are realizable under arbitrary circumstances.6 When 0 is a phenomenological symmetry, i.e., a stable, reproducible, empirical object, then it has the structure of a Husserlian phenomenon.

How does one refer to the experimental profiles of a scientific phenomenon? They are distinguished from one another by the sets of measure numbers that substitute for the symbol 'X' in I X>x, e.g., I X>x becomes Iql, q2, etc.>X, where ql, q2, etc., are the measure numbers provided by measurements with M.7 The measure numbers denominate the profiles and distinguish among them. If this is what is meant by 'describing', then the measure numbers describe, but this, I believe, is not everything a description does; description also gives the sensory qualitative appearances or profiles of a thing.

6 Dirac notation highlights the transformation theory aspect of Husserl's theory of the phenomenon. In classical physics, the ket vectors I X> would be replaced by a classical (n-dimensional) vector space, each vector representing a determinate ob- jective state of the system. In a nonclassical theory such as the quantum theory, ket vectors belong to a Hilbert space, and only those have phenomenological meaning which are contextually linked to measurement.

7The 'X' (in I X>,) will be replaced, after measurement, by some set of definite numbers, qi, q2, etc., standing for one complete set of characteristics for a given context of measurement. It is usually assumed that the profiles of a scientific phenomenon exist antecedently to measurement and are not constituted by the act of measurement. This is the source of the view-held by Husserl and many others -that measurement merely "idealizes" aspects of phenomena already there. I criticized such views in my "Husserl's Later Philosophy of Science"; cf. also my "Natural Science as a Hermeneutic of Instrumentation," Philosophy of Science, L, 3 (1983): 181-204. Cf. also Hacking, Representing, p. 240.

PHILOSOPHICAL SIGNIFICANCE OF EXPERIMENTATION 519

How do the phenomena appear to SX? The appearances of a phe- nomenon are a function of the (usually) standard measuring context M; this "dresses" the phenomenon 0 qualitatively with the charac- teristic set of profiles I ql, q2, etc.>x. Using the analogy with our bodily senses and sensory powers that "dress" everyday perceptual objects with color, texture, hardness, smell, etc., as well as size and shape, M in like manner "dresses" scientific objects as perceptual objects for our knowing in characteristic sets of sensory-technologi- cal "garb." The description of the phenomenon is both quantitative and qualitative.

The measure numbers ql, q2, etc., are obtained from a "reading" of the measuring instruments M (cf. Heelan, 206/7). What is the connection between the preparation-cum-presentation of the phe- nomenon 0 and the numbers "read" from the signals? In the first place, one may validly "read" numbers from the instruments only when the phenomenon 0 is present to Sx, for only then do the events (and numbers) signal the empirical profiles of a phenomenon 0 "dressed" by the equipment M (Galison, 73/4, 88). In the second place, having the right numbers does not guarantee the existence of a phenomenon, for there are other factors involved, such as the instruments, standard procedures, experimental skills, laboratory traditions, and the social context of the research community (Gali- son, 86-110). In the third place, having the phenomenon does not depend on having one (uniquely) right set of numbers, for different laboratory traditions may produce systematically divergent mea- sures.8 Alternatively, the phenomenon could be the outcome of a different theoretical background (classical, say, rather than relativis- tic, giving a different set of characteristic numbers) and different instrumentation.9 Just as a musical score always goes together with performer, instrument, audience, and musical tradition, without which there can be no music, so a theory always goes together with experimenter, equipment, laboratory traditions, and the social

'According to J. S. Hunter, "The National System of Measurements," Science, ccx (November 21, 1980): 869-874, for almost all measures other than the Interna- tional System of Units, repeatability (within a single laboratory) and reproducibility (among different laboratories) is poorly estimated, implying the existence of differ- ent and virtually divergent laboratory traditions for many scientific measures. Some of these divergences usually taken to be random may conceal undisclosed systematic factors.

9 Consider the history of the theory of the electron (Galison, 31-52), or the history of the theory of the positron (Galison, 86-110), first as related to the "birth-cry of atoms," and then as due to Dirac pair-production, or the history of the theory of the muon (Galison, 126-131), first as the "red" electron that caused cosmic ray showers, and then as the cosmic "green electron" with singular pene- trating power (cf. also the general discussion in Galison, 252-262).

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context of science, without which there can be no scientific phenomenon.

Although the measured values of measure numbers are often taken to be data, strictly speaking data are not-and should not be taken to be-just numbers, but phenomenological profiles IX>X. These are experimental state vectors individuated by their individ- ual set of measure numbers. The true datum is the vector I ql, q2,

etc.>X. Much discussion of the relationship between theory and data, even of the more enlightened kind, such as Robert Ackermann's, is unsatisfying for want of a distinction among the following: (1) mea- sure numbers, (2) the model state vector I X>, specified by the num- bers, and (3) the phenomenological state vector IX>x.

Let us take a closer look at theory. Every "reading" of the mea- suring instruments in terms of measure numbers supposes a theoret- ical model. I have chosen to represent such a model by a set of Dirac vectors IX>,, with its transformation groups defining its model in- variants or symmetries. The theoretical vector I X>, is linked with the empirical profile I X>. through the events-"measurement events" -that occur in the measuring instruments (cf. Galison, 126-131).

Consider S.. For S,, the "measurement events" play a part in the constitution of the phenomenon-for-Sr. Measurement "dresses" the phenomenon 0 with a set of characteristic profiles. The "measure- ment events" are not profiles of 0; they are no more profiles of 0 than, say, red patches are profiles of a strawberry, for a profile is experienced as nothing but the presence of a perceptual object under one of its profiles. A profile of a red strawberry is one particu- lar view of a red strawberry; a red patch is something on its own (from which possibly one may infer the presence of a strawberry or something else), but it is not nothing but the presence of a straw- berry. (How right are the arguments of those-Wilfred Sellars and Husserl-who reject the "Myth of the Given"!)

THEORY AS SEMANTICALLY DESCRIPTIVE ONLY IN SOCIAL CONTEXT

Now consider St. For St these "measurement events" are potentially "readable" events, that is, they are signals, subject to the proviso that, at the time of the "reading," the phenomenon is present to S,,. The process of passing from the measurement event as signal (which is physical) to a number (which is nonphysical) is a species of inter- pretation; it is what we do when, for example, we "read" a numeral (a physical sign or signal) as a number (that which under the right circumstances the numeral is taken to signify). Measurement events are then not just plain events, like the red patches mentioned above, but they are the physical signifiers of theoretical vectors, those

PHILOSOPHICAL SIGNIFICANCE OF EXPERIMENTATION 521

which within the experimental situation are characterized by mea- sure numbers.'0

From the standpoint of St, the measurement events qua signals comprise a semiotic system, that is, a system of differences which functions as such. Events comprise a semiotic system, not because of any features the events may have as physical events but because, as a system of differences, they can function as signifiers. Semiotic events may take many forms and still remain events of the same semiotic system (cf. Galison, 248/9). Signifiers, moreover, are timeless and ideal, and so they can be taken to refer to past or future phenomena. Semiotic events, then, partake of a certain physical arbitrariness; by social convention, however, they will have standardized or canonical shapes. What they signify-their semantic meaning-comes in part from the abstract theoretical model I X>, and in part from the con- text of use. What they refer to is the phenomenon 0 under its set of profiles I X>x. The theoretical model I X> now appears from the standpoint of St to be a kind of langnage under which the reference phenomenon with its empirical profiles IX>. is described. Such a relationship is hermeneutical in the typical epistemological sense of that term.

The syntax of that "language" is mathematical; of itself it provides no more than what Husserl would have called a formal ontology or a possible formal ontology, that is, empty schemata of categories of things." Its semantics, however, is tied up with the standardized experimental praxis within which it is used. Semantically it needs a social-historical-technological context to complete its meaning, and this is an open context (Galison, 254). From the point of view of St, then, the following analogy holds: the theoretical model (e.g., elec- tron,) is to (the kind of) phenomenon (e.g., electronj) as the linguistic model (the abstract signifier) is to the signified (the kind of thing the phenomenon is). So far I have been speaking of the research role St.

It is different for S.. What is overlooked when one looks out from the standpoint of S, alone is the constitutive function that the mea- surement events play in the preparation-cum-presentation of the phenomenon 0 within the experimental role S,. A semiotic sign or signal connotes a semantical meaning. It is not generally the case that a semiotic sign also functions to constitute its referent object as an

10 For the nature of semiotic systems, see, e.g., Ferdinand de Saussure, Course in General Linguistics, Wade Baskin, trans. (New York: Philosophical Library, 1959), or textbooks in semiotics.

" See, for example, Husserl, Formal and Transcendental Logic, Dorian Cairns, trans. (The Hague: Nijhoff, 1969), p. 120.

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object-for-knowing. Measurement events do just this, for they be- long to the process whereby S. constitutes the phenomenon as present, knowable, and actually known. This process is also herme- neutical, not now in the epistemological sense, but in an artistic-"existential" or "ontological"-sense, as resulting from a species of experimental performance.'2 Let me clarify this.

Consider, for example, the way a violinist addresses her instru- ment with the bow in order to produce a piece of music. The bow in this case is guided by a memory of the piece to be realized, its position on the strings interprets the needs of the memorized piece, and the sounds produced are in turn interpreted by the listening ear. The score is the theoretical "description" of the piece, it stands for I X>t; the score alone, however, is insufficient for a performance: to have music, one needs in addition an instrument, a performer, a place, an audience, and much besides. For example, performances fulfill different purposes: to teach, to rehearse, to celebrate, etc. Finally, every performance relates to some historical tradition of good performance.

But most important of all, for every good performer, the role of the score undergoes a transformation when it ceases to be a theory and becomes instead a mnemonic, then the artist's scorebook be- comes a set of "places" or topoi, the function of which is to remind the artist of the suites and sequences to be performed. As such it is a local, personal, contextual, historical, technological, and artistic guide, it an open or endless set of memory cues, it is no longer a universal theoretical prescription. Such a mnemonic belongs to the tradition of (what Frances Yates calls) "the art of memory."

Just so in science, once a skilled experimenter knows how within a laboratory tradition to prepare and present a scientific phenome- non, theoretical models become converted into mnemonics for per- formance and demonstration. The last word in scientific research is then with Sx. Theory as such has a formal place only up to the moment when a laboratory tradition permits the realization and re- producibility of stable phenomena suitable for the research needs of the social-historical situation; then it can drop out (Galison, 244, 252-262; and Crease, 337-350) for it is now realized in praxis.

12 Methodological or epistemological hermeneutics is the conscious and deliber- ate work of interpreting a text or a set of signs or symbols. Existential hermeneu- tics, introduced by Martin Heidegger, is that ontological character of all human understanding whereby it interprets life in terms of Being. For a useful survey, see Josef Bleicher, Contemporary Hermeneutics (Boston: Routledge & Kegan Paul, 1980). Joseph Rouse's Knowledge and Power (Ithaca: Cornell, 1987) is an impor- tant recent work introducing Heideggerian hermeneutics to the philosophy of natural science.

PHILOSOPHICAL SIGNIFICANCE OF EXPERIMENTATION 523

When the last word is said, how does S. use the language of theory? Substantive terms used in the theory, such as 'electron', etc., refer to phenomena, i.e., to electron,, etc. Each kind of phenomenon is defined in terms of its characteristic set of profiles, e.g., of mass, charge, spin, lepton number, strangeness, etc.; these are the compo- nents of I X>.,. In each category, the profiles are distinguished from one another by measure numbers that specify and distinguish the contextually realizable vectors of the theoretical model. Some of these measure numbers may be additive, some ordinal, and some merely serve to make discriminations. The descriptive qualities of the phenomenon-what I mean by the dress of the phenomenon-are given by the kinds of standard preparation devices or laboratory practices established by the research community. When the last word is said, the vocabulary of theory remains, but no longer as "theory-laden"; its meaning has become instead "praxis-laden" (cf. Galison, 255).

Whether or not the memory of its theoretical origins is retained, the phenomenon becomes-or seems to become-a part of nature. And though the old terms have their origins in theory and continue to be used, their semantic content changes, bypassing theory and signifying directly the characteristic empirical qualities of the "dressed" phenomenon. That "naturalized" artifact of human cul- ture, the scientific phenomenon, is now, in the sense appropriate to the historical culture of that scientific community, a thing of nature. In our culture, electrons, positrons, muons, and possibly neutral currents are things of nature.

REALISM, ANTIREALISM, OR IDEALISM?

So much for the epistemological question. What now about the onto- logical question? If phenomena-i.e., perceptual objects-are real, then scientific phenomena are real. Then electron,, positrons, muon,, etc., are real and belong to appropriate regional ontologies of the cultural-historical world in which we presently live. As for black holes, quarks, and such like, about which physicists are pres- ently undecided, one will say that laboratory physicists will decide eventually whether these are-can be made to exhibit the phenome- nological symmetries of-scientific phenomena (cf. Galison, 126-131). If they become phenomena, then they are-i.e., they become for us, for our culture-real. Reality, in this view, is natural- istic and evolutionary, but people and praxis are what provide it with the categories of the real.13 Within this picture, the objects of

" Of those who defend a naturalistic evolutionary realism of this kind, some, such as C. S. Peirce, belong to the pragmatist tradition and some, such as Juirgen Ha- bermas, to the Marxist tradition.

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theory-electron,, positront, etc.-are ideal semiotic entities like words, and, like words, they represent no more than empty schemata of an indeterminate and undecidable formal ontology outside of social-historical-technological contexts.

If, to the contrary, one takes formal ontologies to give categories of reality apart from the means of realizing or fulfilling the schemata they define, then theoretical entities such as electron,, positront, etc., should be taken to be, not as in the first position the meanings of word-like semiotic entities, but to refer to real categories indepen- dently of the social-historical-technological context of experimental fulfillment. This Platonizing position is today called "Scientific Realism." 14

There is a third or transcendental position that lies in between the two just mentioned and has certain attractive features. Husserl gave it preference in his own philosophy of science. In this view, theoreti- cal models are not constitutive of an ontology-they are not the categorial contents of a realism-but they are nevertheless univer- sally and transcendentally regulative for all lifeworlds, and they are exemplified in historical culture-relative ways. The fulfillment of such formal conditions then is not a contingent social-historical-tech- nological event as it would be for the first position, but a necessary -though not a sufficient-condition governing all constitutions of phenomena and all constitutions of historical life-worlds. The neces- sity in question belonged, as Husserl thought, to the privileged status of scientific knowing.

My personal view tends to favor the first position. I have criticized Husserl's view in a paper cited above. I find that the reasons he gave are bad reasons. Whatever choice is made, it has to be made against a background that is much broader than that of science itself, an open background that involves history, culture, religion, and art, and the other ingredients of experimental performance so well described and analysed by-to mention just two-Galison and Hacking.'5

PATRICK A. HEELAN

State University of New York/Stony Brook

14 Wilfred Sellars gave the now classical defense of scientific realism in "Philoso- phy and the Scientific Image of Man," in Science, Perception, and Reality (Lon- don: Routledge & Kegan Paul, 1963), pp. 1-40. Of particular note among the many recent works on this topic are Clifford Hooker, A Realistic Theory of Science (Albany: SUNY Press, 1987); Rom Harre, Varieties of Realism (New York: Black- well, 1986); and Scientific Realism, Jarrett Leplin, ed. (Berkeley: California UP, 1984).

15 For an excellent analysis and critique of the current state of the question concerning truth and realism in science, see Joseph J. Kockelmans, "On the Prob- lem of Truth in the Sciences," in Proceedings and Addresses of the American Philosophical Association, LXI, Suppl. (1987): 5-26.