Hacking

Hacking Notes Vincent F. Hendricks Department of Philosophy and Science Studies University of Roskilde [email protected] March 2, 2001

1

Realism and Anti-Realism Scienti…c realism says that the entities, states, processes described by correct theories really exist. ... Even when our sciences have not yet got things right, the realist holds that we often get close to the truth, p. 21. Anti-realism says the opposite; there are no such things as electrons ... The elctrons are …ctions. Theories are adequate or useful or warranted or applicable, but no matter how much we admire the speculative and technological triumphs of natural science, we should still not regard even its most telling stories true. p. 21. So far as I’m concerned, if you can spray them they are real. p. 23.

Now Hacking’s point is that the traditional debate between realism and antirealism has been derailed by the fact that the typical positions pertaining to realism and anti-realism have been derived largely from epistemological, methodological, semantical and considerations of rationality (the upper line) rather than by consulting science. This is further emphasized by his sub-division making up the realism and anti-realism debate, p. 28: 1. An ontological ingredient. 2. A causal ingredient. 3. An epistemological ingredient. One type of anti-realism rejects (1) (instrumentalism), the other rejects (3) (constructive empiricism): My realism about theories is, then, roughly (1) and (3), but my realism about entities is not exactly (2) and (3). p. 29.

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Hacking can have it both ways because he distinguishes between: ² Realism about entities says that a good many theoretical entites really do exist. Anti-realism denies that ... or less dogmatically, it may say that we have not and cannot have any reason to suppose thay are not …ctions. They may exist, but we need not assume that in order to understand the world. p. 27. ² Realism about theories says that scienti…c theories are either true or false independent of what we know: science at least aims at the truth, and the truth is how the world is. Anti-realism says that theories are at best warranted, adequate, good to work on, acceptable but incredible, or whatnot. p. 27. Here is the crux: We represent and intervene. We represent in order to intervene, and we intervene in the light of representation. Most of today’s debate about scienti…c realism is couched in terms of theory, representation and truth. The discussions are illuminating but not decisive. This is partly because they are so infected with intractable metaphysics. I suspect that there can be no …nal argument for or against realism at the level of representation. When we turn from representation to intervention ... anti-realism has less of a grib. p. 31.

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Positivism, Logical Positivism and Constructivism Empiricism

Six cardinal points of characterization: 1. Veri…cation (or some variant such as falsi…cation). 2. Pro-observation. 3. Anti-cause. 4. Downplaying explanation. 5. Anti-theoretical entities. 6. 1 + 5 = against metaphysics. p. 42.

2.1

Positivism Positive science allows propositions to count as true-or-false if and only if, there is some way of settling their truth value. Comte’s Course of Positive Philosophy is a grand epistemoplogical history of the development of the sciences. p. 45. 2

Hume did not believe in the invisble bouncy balls or atoms of Robert Boyle’s mechanical philosophy. p. 49 Comte equally disbelieved in the atoms and aether of the science of his time. p. 49.

2.2

Logical Positivism Logical positivism had no such simplistic opportunities. Members of the Vienna Circle believed the physics of their day: some had made contributions to it. ... Hence arose , in the extreme versions of logical positivism, a doctrine of reductionism. p. 50.

2.3

Constructive Empiricism

Against the logical positivists, van Fraasen says that theories are to be taken literally. Against the realist he says that we need not believe theories to be true. He invites us instead to use two further concepts: acceptance and empirical adequacy. Science aims to give us, in its theories, a literally true true story of what the world is like. [Van Fraassen, p. 8.] Science aims to give us theories which are empirically adequate; and acceptance of a theory involves as belief only that it is empirically adequate. [Van Fraassen, p. 8.], p. 51

2.4

IBE—and Explanation

Realism to be saved by IBE (Aristotle, Peirce, Hanson, Harman, Bird, ...)? Three arguments for: 1. Simple inference argument, p. 53. 2. Cosmic accidents argument, p. 54. 3. Science and convergence, p. 55. Five arguments against: 1. Monotonic increase 6= convergence, p. 55.

2. Growth of knowledge without realism, p. 56. 3. It’s not theory which increase, (a) but phenomena which increase, (b) technological and manipulative skills increase, (c) scienti…c reasoning increase. 4. One takes knowledge to be a given fact and characterize truth in terms of it. 3

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Pragmatism—“Pragmaticism” Peirce tried to replace truth by method. Truth is whatever is in the end delivered to the community of inquireres who pursue a certain end in a certain way. p. 59. Peirce is ... quite a good experimenter. Measurement, in his experience, converges, and what it converges on is by de…nition correct. He thought that all human beliefs would be like that too. p. 60. Truth was, roughly, whtever hypothesizing, induction and testing settled down upon. p. 60. There is, however, in James and Dewey, and indi¤erence to the Peircian vision. They did not care what beliefs we settle on in the long run. Thus, pragmatism branches: There are Peirce and Putnam on the one hand, and James, Dewey and Rorty on the other. Both are anti-realist, but in somewhat di¤erent ways. Peirce and Putnam optimistically hope that there is something sooner or later, information and reasoning would …nally settle upon. ... Rorty’s version of pragmatism is yet another language-based philosophy, which regards all out life as a matter of conversation, p. 63.

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Incommensurability

4.1

Kuhn’s model of science: pre-science y

4.2 4.2.1

normal science y anomalies y crisis y revolution puzzle-solving

Incommensurability Topic incommensurability

² Nagel. Bridgelaws, reductions and theoretical subsumption. ² No accumulation and subsumption. 4.2.2

Dissociation A long enough time, and radical enough shifts in theory, may make earlier work intelligible to a later scienti…c audience. An old theory may be forgotten, but still be intelligible to the modern reader who is willing to spend time relearning it. On the other hand some theories indicate so radical a change that one requires something far harder than mere learning of a theory, 69.

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4.2.3

Meaning-incommensurability The third kind of incommensurability is not historical but philosophical. It starts from asking about the meaning of terms that stand for theoretical, unobservble entities. p. 72.

This type of incommensurability worries Hacking: That is incommensurability with a vengeance. There is no common measure for any two theories that employ theoretical terminology because in principle they can never discuss the same issue. There cannot be theoretical propositions that one theory shares with its successor. Nagel’s doctrine of subsumption becomes logically impossible, simply because what T says cannot be even asserted (or denied) in the successor theory T ¤ ., p. 73.

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Reference, Putnam and Internal Realism

Putnam: Meaning is a vector: < semantic marker, syntactic marker, stereotypes, extension > Recall: 1. Meanings ain’t in the head—attack on Fregeian sense and reference. 2. Twin-Earth. 3. Division of Linguistic Labor. Now When Putnam developed his theory of reference he was still a scienti…c realist. Meaning-incommensurability is bad for scienti…c realism, so it behooved Putnam to develop at theory of meaning that avoided the pittfals of incommensurability. That is a negative result. There is also a positive one: ... Putnam’s account of reference provides the realist with the obvious reply: Milikan measured the charge on the electron. Lorentz, Rutherford, Bohr ... were all talking about electrons. They had di¤erent theories about electrons. Di¤erent stereotypes of electrons have been in vogue but it is the reference that …xes the sameness of what we are talking about. p. 81. It is a defect of Putnam’s essays that he favours …ctions to facts. The facts reveal some ‡aws in Putnam’s simpli…ed meaning of “meaning”. p. 81. Examples: 5

1. Dubbing the electron, p. 82-84. 2. Acids: bifurcating kinds, p. 84-85. 3. Caloric: the non-entity, p. 86-87. 4. Mesons and muons, p. 87-90. I have not wanted to advance a philosophical theory of meaning. I have had only the negative purpose, of describing a theory of meaning that is pretty naturalfor a wide range of linguistic practice, and which does not invite talk of incommensurability. It is the kind of theory that scienti…c realists need. p. 91.

5.1

Excursion—Putnam’s Internal Realism His [Putnam’s] is a philosophy founded upon re‡ections on language, and no such philosophy can teach anything positive about natural science. p. 92.

De…nitions of 1. External and 2. Internal realism, see. p. 92-93. Putnam’s internalist can make no sense of a complete theory of the interesting universe which is entirely adequate but still false. I’m an externalist, and can make no sense of it either, but for a di¤erent reason. I cannot understand the idea of a complete theory of our interesting universe. A fortiori, I don’t understand the idea that such a theory might be adequate but false, for the idea of such a theory is itself incoherent. p. 93. A distinction between three kinds of warfare: 1. Scienti…c realism, as opposed to anti-realism about science, is a colonial war ... I call this a colonial war because one side is trying to colonize new realms and call them reality, while the other side opposes such fanciful imperialism. 2. Then there is a civil war ... I call this a civil war because it is fought on the familiar ground of everyday experience. 3. Finally there is total war, chie‡y a product of more recent times. Maybe Kant began it. p. 96. Putnam once argued for scienti…c realism in a colonial war. He now argues for a position, which he says is like Kant’s, in a total war. Let us grasp Kant’s postion in more detail before tackling Putnam’s. p. 96. Summarizing Kant: 6

This is an empirical realism that grants ‘the objective validity, of space, in respect of whatever can be presented to us as objects’. At the same time it is a transcendental idealism which asserts that space ‘is nothing at all ... once we withdraw ... its limitation to possible experience and so look upon it as something that underlies things in themselves.’ p. 97. According to Hacking, Putnam wrongly anagolizes his own view with Kant’s on two counts; 1. wrt. truth, p. 98. 2. wrt. theoretical entities and ding-an-sich, p. 99-100. Internal Realism and Lövenheim-Skolem’s theorem (stated in paragraph): You write down some postulates that you hope .... a set no bigger than the set of natural numbers. p. 103. Concluding Putnam returns the theorem to seeming paradox. He makes a correct generalization. It applies to any domain of individuals, say cats and cherries. Take as the axioms oll truths about these—all truths that I shall ever utter, or that people will ever utter, or simply all the genuine truth expressible in a …rst-order language. Whatever you choose, there will be unintended interpretations: moreover when you pick two kinds of objects, cats and cherries, and use a short list of truths, we can get the intended interpretation about cats to map on to the uintended interpretation about cherries. p. 103. Hacking’s points against Putnam’s conclusion: 1. The Lövenheim-Skolem theorem is about …rst-order logic which is not necessarily the language of science. 2. Second-order quanti…cation. 3. Indexicals. 4. Language is more than talking. 5. No need for a theory of reference to refer. 6. Dubbing entities is not necessarily linguistic. 7. The Lövenheim-Skolem theorem is non-constructive. 8. ... p. 107.

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Putnam’s internal realism comes to this: Within my system of thought I refer to various objects, and say things about those objects, some true, some false. However, I can never get outside my system of thought, and maintain some basis for reference which is not part of my own system of classi…cation and naming. That is precisely empirical realism and transcendental nominalism. p. 109.

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Imre Lakatos and a Surrogate for Truth The two current issues of philosophy of science are epistemological and metaphysical. Lakatos seems to be talking about the former. p. 112. I urge that they are about something other than method and rationality. He is important precisely because he is addressing, not an epistemological issue, but a metaphysical one. He is concerned with truth and its absence. p. 112. So they tried to …nd a substitute for truth. In the Hegelian tradition, they said it lies in the process, in the nature of the growth of knowledge itself. p. 113.

6.1

On Falsi…cationisms

All three emphasize the testing and falsifying of conjectures rather than verifying or con…rming them. p. 114 ² Popper1 : ‘people propose, nature disposes’ ² Popper2 : ‘people propose, nature disposes’ + no theory is rejected or abandoned unless there is a better rival theory in existence. ² Popper3 : ‘people propose, nature disposes’ + no theory is rejected or abandoned unless there is a better rival theory in existence + one theory is better than another if it makes more novel predictions. p. 115.

6.2

Researh Programmes

A research programme “is a sequence of developing theories that might last for centuries, and which might sink into oblivion for 80 years and then be revived by an entirely fresh infusion of facts or ideas”. p. 116. Keywords: ² Hard core. ² Protective belt. ² Negative heuristic. 8

² Positive heuristic. ² Progress and degeneration of research programmes: “What makes a research programme good or bad. The good ones are progressive, the bad ones are degenerating ... A programme is simply progressive, if it is both theoretically and empirically progressive. Otherwise it is degenerating. p. 117. ... We cannot tell whether a programme is progressive until after the fact.

6.3

Objectivity and Growth of Knowledge He does not want a replacement for a correspondence theory of truth, but a replacement for truth itself. p. 119. There is no forward-looking rationality, but we can comprehend the objectivity of our present beliefs by reconstructing the way we got there. Where do we start? With the growth of knowledge. p. 119.

1. First, one can see by direct inspection that knowledge has grown. 2. Secondly, there is no arguing that some historical events do exhibit the growth of knowledge. p. 120. 3. The growth of scienti…c knowledge, given an intelligent analysis, might provide a demarcation between rational activity and irrationalism. p. 120. 6.3.1

Histories and Realms This idea about the growth of knowledge into something objective and non-human was foreshadowed in his …rst major philosophical work, Proofs and Refutations (see quote, p. 123). One of the lessons of Proofs and Refutations is that mathematics might be both the product of human activity and autonomous, with its own internal characterization of objectivity which can be analyzed in terms of how mathematical knowledge has grown. Popper has suggested that such objective knowledge could be a ‘third word’ of reality, and Lakatos toyed with the idea ... ‘The products of human knowledge; propositions, theories, systems of theories, problems, problemshifts, research programmes live and grow in the third world; the producers of knowledge live in the …rst and second world. p. 124.

6.3.2

Rational Reconstruction

Lakatos has a problem, to characterize the growth of knowledge internally by analyzing examples of growth. There is a conjecture, that the unit of growth 9

is the research programme and that research programmes are progressive or degenerating and, …nally, that knowledge grows by the triumph of progressive programmes over degenerating ones. p. 124 If the data and the Lakatosian conjecture cannot be reconciled, two options remain: 1. First, the case history may itself be regarded as something other than the growth of knowledge. p. 125. 2. Tracking progressive sequence of problemshifts in order make a distinction between rationalism vs. irrationalism while at the same time breaking with Kuhn. p. 127.

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Experiment

Bacon taught us that not only must we observe nature in the raw, but that we must also “twist the lion’s tail”, that is, manipulate our world in order to learn its secrets. p. 149. Experimentation has a life of its own. p. 150

7.1

Theory and Observation

I am concerned solely with the question of the strong version: must there be a conjecture under test in order for an experiment to make sense? p. 154. 1. It was not an interpretation in the light of theory, for Davy had initially no theory. p. 155. 2. They saw what they saw because they were curious, inquisitive, re‡ective people They were attempting to form theories: But in all these cases it is clear that the observations preceded any formulation of theory. p. 156. 3. He did not interpret his experimental …ndings in the light of his wrong theory. He made some phenomena for which any theory must, in the end, account. p. 157. 4. Thus I make no claim that experimental work could exist independently of theory. That would be the blind work of those which Bacon mocked as mere empirics. It remains however, that much truly fundamental research precedes any relevant theory whatsoever. p. 158. 5. Some profound experimental work ... from an entirely di¤erent quarter. p. 159. 6. The happy family that I have just described is the intersection of theory and skilled observation. p. 160. 10

7. A question posed in terms of theory and experiment is misleading because it treats theory as one rather uniform kind of thing and experiment another ... We have seen some varieties of experiment, but there are also other relevant categories, of which invention is one of the most important ... But there is another road, in which inventions proceed at their own practical pace and theory spins o¤ on the side. p. 163. 8. The experimental results in this list were established long before there was a theory around to …t them together. ... the theory did not come directly out of the data, but from much more general insights into atomic structure. p. 165.

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Observation

Commonplace facts about observation have been distorted by two philosophical fashions: ² Semantic ascent. ² Domination of experiment by theory. p. 167 Now 1. Observation, as a primary source of data, has always been a part of natural science, but it is not all that important. 2. But this is less a matter of the philosophers’ observation-as-reportingwhat-one-sees, than the sense of the word we use when we call one person observant while another is not. p. 167 3. Experiment supersedes raw observation. p. 168 4. Observation is skill. p. 168. 5. This is the wrong ground for attack. There are plenty of pre-theoretical observation statements ... p. 168. 6. Althrough there is a concept of seeing with the naked eye scientists seldom restricts observation to that.

8.1

Denying Central Dogmas

1. Positivistic reduction of theoretical statements to observations statements, p. 169. 2. Once the distinction between observation and theory was made so important, it was certain to be denied. p. 169.

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3. Hanson also points out that we tend to notice things only when we have expectations, often of a theoretical sort, which will make them seem interesting or at least to make sense. That is true but it is di¤erent from the theory-loaded doctrine. 4. In want to cancel something ... I shall insist on the truism that experimenting is not stating or reporting but doing - and not doing things with words. p. 173. 5. There have been important observations in the history of science, which have included no theoretical assumptions at all. - Herschel example. p. 176. 6. We might call this doctine that noticing is theory-loaded. p. 179. 7. If we want a comprehensive account of of scienti…c life, we should in exact opposition to Quine, drop the talk of observation sentences and speak instead of observation. 8. It is precisely the disunity of science that allows us to observe (...) another aspect of nature (...) Of course whether or not two domains are connected itself involves, not exactly theory, but a hunch about the nature of nature. p. 183. 9. Observation, in the philosophers’ sense of producing and recording data is only one aspect to experimental work. p. 185. 10. A philosophy of experimental science cannot allow theory-dominated philosophy to make the very concept of observation become suspect.

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Microscopes

But why should a philosopher care how it [microscope] works? Because it is one way to …nd out about the real world. The question is this: How does it do it? The microscopist has far more amaxing tricks than the most imanginative of armchair students of philosophy. p. 186. 1. That is the …rst lesson: you learn to see through a microscope by doing, not just by looking. p. 191. 2. One needs ttheory to make a microscope. You do not need theory to use one. p. 191. 3. The observations and manupulations seldom bear any load of physical theory at all, and what is there is entirely independent of the cells and crystals being studied. p. 191. 4. Theory has only a modest amount to do with building these ingenious devices. The theory involved is mostly of the sort you learn in Physics I in college. It is the engineering that counts. p. 199. 12

Conclusion: But if we conclude that we see with the light microscopes, does it follow that the objects we report seeing are real? No. For I have said only that we should not be stuck in the nineteenth-century rut of positivism-cum-phenomenology, and that we should allow ourselves to talk of seeing with the microscope. Such a recommendation implies a strong commitment to realism about microscopy, but it begs the question at issue. ... The physicist is a realist too, and he shows this by using the word ‘see’, but his usage is no argument that there are such things. p. 208. Does microscopy then beg the question of realism? No: 1. We are convinced of the structures that we observe using various kinds of microscopes. p. 209 2. We are convinced about the structures we seem to see because we can interfere with them ... p. 209. 3. We are convinced because instreuments using entirely di¤erent physical principles lead us to observe pretty much the same structures in the same specimen. p. 209 4. We are convinced by our clear understanding of the most of the physics used to build the instruments that enable us to seem, but this theoretical conviction plays a relatively small part.

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Hackian Structure

A tripartite division of acitivities: I call it speculation, calculation and experimentation. p. 212.

10.1

Speculation By speculation I shall mean the intellectual represenation of something of interest, a playing with and restructuring of ideas to give at least qualitative understanding of some general feature of the world. p. 213.

10.2

Calculation Thus, Kuhn’s articulation must denote two kinds of thing, the articulation of theory and the articulation of experiment. I shall arbitrarily call the more theoretical of these two activities calculation. p. 214. 13

10.3

Hypothetico-Deductivism. If speculation intends a qualitative structure for some domain, and experimentation, as I claim sometimes pursue a life of its own, what then is the …t between the two? Answer: calculation makes the fairly tight hypothetico-deduktive structure that you sometimes …nd in an elementary textbook. Calculators write the dictionary. The build the semantic bridge between theory and observation. Speculation and experiment need not in general be closely connected, but the activity I call calculation brings them close enough to discern a quantitative …t between them. p. 215.

10.4

Models We begin with speculations that we gradually cast into a form from whence experimental tests may be deduced. Not so. There is an enormous wide ranging intermediary activity best called modelbuilding. p. 216

This leads us to the following conception: 1. p. 217 2. p. 217 3. The models ... p. 217

10.5

The Direction of Science I respond to this in an inductive way: Every single year since 1840 physics alone has used sucessfully more (incompatible) models of phenomena in its day to day business, than it is used in the preceding year. The ideal of science is not unity but absolute plethora. But although there are such approximations away from the truth, there are far more approximations towrds the truth. p. 218 I myself prefer an Argentine Fantasy ... p. 219

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Phenomena I say that often they create the phenomena which then become the centrepiece of theory. p. 220. A phenomenon is noteworthy. A phenomenon is discernible. A phenomenon is commonly an event or process of a certain type that occurs regularly under de…nite circumstances.

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Despite the usage, many of the ancients held that phenomena are changing objects of the senses, as opposed to essences, the permanent reality. Thus, phenomena were in contrast to reality. A present day positivist like Van Fraassen holds that phenomena are the only reality. The word “phenomena” are neutral between these two dosctrines. p. 221 When the physicists gor their hands and minds on a truly instructive phenomena, thay came to call it an e¤ect. p. 224. Phenomena and e¤ects are in the same line of business: noteworthy discernible regularities. The words “phenomena” and “e¤ects” can often serve as synonyms, yet they point in di¤erent directions. Phenomena remind us, in the semiconscious repository of language, of events that can be recorded by the gifted observer who does not intervene in the world but who watches the stars. E¤ects remind us of the great experiments after whom, in general we name the e¤ects: the men and women, the Compton and Curie, who intervened in the course of nature, to create regularity which, at least at …rst, can be seen as regular (anomalous) only against the further background theory. p. 226. I suggest, in contrast, that the Hall e¤ect does not exist outside of certain kinds of apparatus. Its modern equivalent has become technology, reliably and routinely produced. The e¤ect, at least in a pure state, can only be embodied in such devices ... In nature there is just complexity, which we are remarkably able to analyze. We do so by distinguishing, in the mind, numerous di¤erent laws. We also do so, by presenting, in the laboratory, pure isolated phenomena. p. 226. There is no more familiar dictum than experimental results must be repeatable. On my view that works out as something as a tautology. Experiment is the creation of phenomena; phenomena must have discernible regularities—so an experiment that is not repeatable has failed to create a phenomenon. p. 229. This is a pseudo-problem because, roughly speaking, no one ever repeats an experiment. Typically serious repetitions of an experiment are attempts to do the same thing better—to produce a more stable, less noisy version of the phenomenon. A repetition of an experiment usually uses di¤erent kinds of equipment. p. 231.

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12

Baconian Topics In Chapter 12 I divided Bacon’s rational faculty into speculation and calculation, claiming that these are di¤erent abilities. What is so great about science is that it is a collaboration between di¤erent kinds of people: the speculators, the calculators, and the experimenters. p. 248 The remarkable fact about recent physical science is that creates new, collective human artifact, by giving full range to three fundamental human interrests, speculation, calculation, and experiment. p. 248

Hacking on social science: Hence we can diagnose p. 248 ... creation of stable phenomena. p. 249.

13

Experimentation and Realism

Experimental work provides the strongest evidence for scienti…c realism. p. 262: 1. The vast majority of experimental physicists are realists about some theoretical entities, namely the ones they use. p. 262. 2. Experimenting on an entity does not commit you to believing that it exists. Only manipulating an entity, in order to experiment on something else, need do that. p. 263 ... There are ways of creating phenomena in some other domain of nature. Electrons.are tools. p. 263. 3. There is in contrast no present set of theories that one has to believe in. If realism about theories is a doctrine about the aims of science, it is a doctrine laden with certain kinds of values. If realism about enities is a matter of aiming electrons next week, or aiming at other electrons the week after, it is a doctrine much more neutral between values. The way in which experimenters are scienti…c realists about entites is entirely di¤erent from ways in which they might be realists about theories. p. 263. 4. I recognize that many a scienti…c realism concerning theories is a doctrine not about the present but about the what we might achieve, or possibly an ideal at which we aim. So to say there is no present theory does not count against the optimistic aim. The point is that such scienti…c realism about theories has to adopt the Peircian principles of faith, hope and charity. p. 265 5. The argument—it could be called the experimental argument for realism— is not that we infer the reality of electrons from our success. We do not make the instruments and then infer the reality of the electrons, as when 16

we test an hypothesis, and then believe it because it passed the test. That gets the time-order wrong. By now we design apparatus relying on a modest number of home truths about electrons, in order to produce some other phenomenon that we wish to investigate. p. 265. 6. We are complertely convinced of the reality of electrons when we regularly set out to build—and often enough succeed in building—new kinds of device that use various well-understood causal properties of electrons to interfere in other more hypothetical parts of nature. p. 265.

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