Guyau

Between Realism and Constructive Empiricism

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There are varieties of scientific realism, but let me begin with the strongest sort. This would be the view that scientific theories, principles, and theoretical entities are factually true or false, that they are the way the physical world is constituted or not, that they are instantiated, as conceived, in the world or not. On this view also, science can come ever closer (even all the way) to ascertaining the truth or falsity of a theory, and so, ever closer to ascertaining a way the world is; by further observations and experiments and their analyses. Even facets of the theory not observable, directly nor indirectly, may be so ascertained of the world, under full-strength realism (Van Fraassen 1980, 7–9; Newton-Smith 1981, 28–29, 37–39; Boyd 1983, 195, 211; Brown 1987, 10–16, 20–22; Miller 1987, 363–67; Suppe 1989, chp. 12).

So far as I know, every realist and every other philosopher of science recognizes a distinction between mathematical existence and physical existence (e.g., Van Fraassen 1985, 303). If it can be established within bounds that a mathematical structure obtains in the physical world, that a structure is instantiated in or is applicable to the physical world, then mathematical existence can lead us to new physical existents: to the planet Neptune, to radio waves, to matter waves, to antimatter, to maximum masses for white dwarf stars and neutron stars, to the top quark, to anyons (between bosons and fermions, in 2D), to phonons, to the magnetic vector potential (via Aharonov-Bohm effect), and to time dilation. Milder sorts of realists and the antirealists, of course, are not going to concede that all of these items should be ascribed physical reality, even though each item has received substantial empirical corroboration. But antirealists and realists alike will agree that the fullness with which a mathematical structure applies to the world, in the specific domain under investigation, has to be established empirically. Any scientific realist must allow that at a given time in the development of science there will be theoretical items about which one should be agnostic concerning their physical reality. For the full-strength scientific realist, however, there is no facet of theory about which one should be agnostic on principle, agnostic always, at any stage of scientific development.

Constructive empiricism is the antirealist position of Bas van Fraassen. The constructive empiricist is, on principle, agnostic about what is physically real when it comes to unobservable elements in a scientific theory. The content of a theory over and above its empirical content should never become accepted as true of the world (agnosticism), though it may rightly become accepted as empirically adequate, as true with respect to observable phenomena (Van Fraassen 1980, 11–13; 1989, 191–93, 213–14, 225–28; 1991, 3–4, 242, 481–82). "A theory is empirically adequate exactly if what it says about observable things and events in this world is true" (Van Fraassen 1980, 12). "Observable things and events" means all the phenomena, not only those actually observed so far or ever in the future. No more than potential empirical adequacy is required to motivate theoretical research programmes; scientific realism is not required (ibid., 12–13, 34, 80–83, 151–52).

Immediately, I find the constructive empiricist stance attractive. We can sense directly, within ranges, that heat is flowing into or out of our bodies. But identification of the object of our sensing as (rate of) heat flow is a theoretical identification of physics and physiology. The thermodynamic concepts of heat and energy are theoretical and are confrontable empirically, by touch or instrument, only in limited ways, not in their whole cloth, through and through.

To the mind of the constructive empiricist, the things that we can know to be physically real are (i) things that we have actually observed, without sense-extending aids nor commonsense-extending inferences, and (ii) things thusly observable but to now less directly observed (ibid., 15–17). In category (i) would be falling, firmness, coldness, snow, trees, tables, and moon rocks (and not "sense data" [ibid., 56–57, 72]). From my earlier list of physical existents that are commonly claimed to have been reached in contemporary physics, only Neptune—because it is category (ii)—counts as physically real in the book of constructive empiricism. When it comes to the conjecture that there is the planet Neptune or the conjecture that Earth's moon is make of rock, empirical adequacy coincides with truth, constructive empiricism coincides with realism (ibid., 72). The divide between constructive empiricism and realism pertains to claims that science has established (or can establish) the existence of the remaining, more subtle items on my list; and we should add to those contentious items, electrons, molecules, DNA strands, viruses, organelles, and even cells (ibid., 16–17, 57–59; Van Fraassen 1985, 256–57). None of these fall into categories (i) or (ii).

It looks to me that the observability requirements of Van Fraassen's constructive empiricism are too restrictive. I should take three steps into realism.

The first step is in response to Ian Hacking's analysis of observations with microscopes. In learning to observe with optical microscopes, one needs to acquire some elementary understanding of the instruments, some skill in scope operation, and skill in manipulating specimens while they are under the scope. The student will "not be able to tell a dust particle from a fruit fly's salivary gland until he has started to dissect a fruit fly under a microscope of modest magnification" (Hacking 1985, 136). Presented to the unaided eye, the dust-or-gland in question is, at best, simply a speck. Under the observability criteria (i) and (ii), we cannot get beyond that speck when it comes to affirming physical existence on account of observation. We put a visible fly on the slide and manipulate it with visible tools. Using the scope, visual observation, though it becomes surely indirect, extends down to organs of fruit fly, even down to particular parts of cells. "The conviction that a particular part of a cell is there as imaged is, to say the least, reinforced when, using straightforward physical means, you microinject a fluid into just that part of the cell. We see the tiny glass needle—a tool that we have ourselves hand crafted under the microscope—jerk through the cell wall" (ibid.). Surely realism about cells, actively observed using various scopes and stains, is justified.

Realism concerning cells is justified by specifics of their observation and manipulation and how these overlap with and directly connect to our normal observations and manipulations (further, Hacking 1985, 152). I do not think that this modest step is a step down a slippery slope to realism concerning all items indirectly but reliably detected and manipulated in physical science (contra Hacking 1982). In a general way, the further we extend the sensitivities and spatial reach of our senses with instruments (consider thermometry and X-ray crystallography), the more high-level theoretical inferences and interpretations are required for ascertaining what we have detected or manipulated. The we just used should include not only the users of instruments, but the designers and manufacturers of those instruments. Science, like industry, is a collective enterprise.

Having taken step one into more realism, I should say that I think Van Fraassen is nonetheless correct in trying to maintain a distinction between detection and observation (further, Brown 1987, chp. 4; Suppe 1989, 119–23; 1997, 406–22). He would say that tracks in a cloud chamber allow us to detect charged particles. The detection is based on observations, but we do not observe the particles themselves in the chamber (Van Fraassen 1980, 17). With such instruments, we have detected, though we have not observed, charged elementary particles such as the electron.

A Scanning Tunneling Microscope (STM) image of the surface of the semiconductor gallium arsenide reveals something looking like aligned beads (Wickramasinghe 1989, 101). We are very sure those arrays of beads are maps of arrays of atoms and molecules. We are not observing those atoms in the STM image. We are inferring them from our understanding of the character of our sensor (electrons and piezoelectrics), sensor motion control system, theory of electron tunneling probability, and signal processing and display. Still, the consilience of observations and manipulations with the STM and our many other current instruments, and consilience of all the observations and manipulations over the last century and more that made those instruments possible is overwhelming: Molecules, atoms, electrons, photons, and radio waves, the existence of all these are now inferred with complete assurance (cf. Friedman 1983, 238–48). It is no longer plausible that atoms are not concrete particulars, as concrete as the lasers they have made possible, as concrete as the rotation of the earth on its axis. Atoms are themselves unobservable, yet we know for sure they exist. This is my second step into realism.

Under step two, by at least 1911, inference to the physical existence of atoms and molecules was warranted, indeed required (Nye 1996, 111–15). By 1900 atoms and molecules were evidenced by Dalton's law of multiple proportions, Gay-Lussac's law pertaining to the volume of gases, Avogadro's law (which made possible the determination of molecular weights), and the kinetic theory of gases (which could approximately predict molar heat capacities). After 1908, when Perrin published his results on the sedimentation distribution of (visible) particles suspended in a still liquid and his measurement of Avogadro's constant, the case for the existence of atoms and molecules was awesomely tight (Wehr and Richards 1967, 4–26).

Hacking, because of his stress upon the effectiveness of experimental manipulation for the getting of real entities, has eschewed realism concerning extragalactic objects (1989). No getting to the physically real, beyond the phenomena, for intergalactic astrophysics. Taking my step two into realism allows that astrophysicists might come to know truths of extragalactic physical reality (Shapere 1993).

Richard Miller has pointed out that constructive empiricism, limiting right scientific inference of physical existence to such a tight compass of observability—what I have cast as category (i) or (ii) observability—is placed in a predicament over Pluto. That planet is observable with the unaided eyesight of astronauts, they could eventually go there, "Pluto exists" we may rightly assert. Yet "the coldness of Pluto is not observable, since humans cannot detect it without instruments. They would die instantly if they tried" (Miller 1989, 362). My first two steps into realism are together sufficient to allow us to assert a physical temperature for a physical planet.

Steps one and two are enough to sanction realism, physical truth or falsity, physical existence or only mathematical existence, for everything on my original list of controversial, unobservable items: radio waves, matter waves, antimatter, maximum masses for white dwarf stars and neutron stars, the top quark, anyons, phonons, the magnetic vector potential, and time dilation.

Now that two-step realism has allowed molecules, atoms, electrons, photons, and radio waves as for sure physical existents, rather than as only empirically adequate theoretical items, Van Fraassen would want to ask: Whose electron got the physical reality? (1980, 214) Is it the electron of Lorentz (1892–1904), a minute spherical volume of negative charge only, possessing no inertial mass, rather its own electromagnetic field inducing a resistance to motion of the electron (now ellipsoidal) when moving, that resistance being its "electromagnetic mass"? Or is it the electron of Einstein-Planck (1905–8), a point particle possessing a fixed nonzero inertial mass in its own rest frame, that mass being encountered as variable with relative velocity by outside frames in motion relative to the electron, "electromagnetic mass" being voided, totally identified with inertial mass? Or is the existence-winning electron that of Thompson, Poincaré, Abraham, Bucherer, Fermi, Frenkel, Dirac, . . . ?

A number of these models of the electron have been eliminated by empirical test. At times the competing models can appear empirically equivalent; that would be the case for Lorentz v. Einstein in 1905 (Zahar 1989, 84). But in time, empirically different implications are teased out of these theories; that is the way of most empirically equivalent theories; the empirical equivalence is temporary (Miller 1987, 419–41). By 1908 the Lorentz v. Einstein-Planck competitors could be tested (Miller 1981, §12.4). The existent, electron, is evidently more like the Einstein-Planck model than the Lorentz model. Even if electrons, taken as existents, as concrete particulars, are here to stay, which of their properties are here to stay? It does not seem reasonable to say we know that electrons are physically real, but that we are agnostic about the physical reality of all properties of the electron. The properties (leaving aside QFT) of the electron we count as essential, for some decades now, are mass, charge, intrinsic spin, and de Broglie wavelength (and less essential, but very important, the electron being a perfect point). Our deepest theory of micromatter is quantum mechanics (with special relativity). Couldn't a surpassing theory yet come along, absorb our quantum mechanics and void mass or charge or intrinsic spin or de Broglie waves in the way that Einstein-Planck voided "electromagnetic mass"? Yes. Physicists have in fact been long anticipating and seeking a deeper theory to fully fuse quantum theory with special and general relativity theory. When that is achieved, will the deepest physical concepts in our ontology—mass-energy, angular momentum, and electric charge (and spacetime? and the invariant spacetime interval?)—be voided in that fusion? Very implausible. These theoretical entities, which we take for concretely physical, have been won through very long hard digging. Insofar as they may become voided, it plausibly would be only as with "electromagnetic mass": tokens of the old concept identified with tokens of a new concept. Existence of the old-concept tokens continue under new-concept tokens.

The most interesting empirical equivalences, to my mind, are those in which the equivalence has been proven mathematically. As Apollonius knew, the apparent motions of moon, sun, or planet about the earth can be modeled equivalently by either of two geometric models, eccenter or epicycle. Their equivalence is geometrically demonstrable. Which of these two models is physically real? I should say, as do many others, that what is invariant between the models is potentially "the undraped figure of nature itself," whereas, the remainder in the models is surely only "the gay-coloured vesture with which we clothe it." The invariant between equivalent and empirically adequate models is closer the physically real.

Again, Schrodinger's wave formulation of quantum mechanics is mathematically equivalent to Heisenberg's matrix formulation. Again we are drawn to the invariant between the formulations as being closer to the unadorned figure of nature.

Consider also Newtonian mechanics. Within the domain of Newtonian mechanics, Lagrangian and Hamiltonian formulations are demonstrably equivalent to the Newtonian. However, the Lagrangian formulation applies to a wider domain including the Newtonian, and the Hamiltonian formulation applies to a wider domain including the Lagrangian (Arnold 1989, 2, 53, 162). Within the Newtonian domain, we might look for what is invariant among the three equivalent formulations for taking as closer to the undraped figure of nature. Then, too, we might rather take the Hamiltonian formulation as closer because it has the widest range of applicability, indicating depth (cf. Stein 1989; Nozick 1998).

Well, there is my third step into realism, the invariants-depth step. It is a shy step, for it only allows one to say one has gotten closer to a physical reality, never that one has reached the final, deepest invariants. Because of the shyness of step three, I believe my three steps together land me shy of full-strength scientific realism.

References

Arnold, V.I. 1989. Mathematical Methods of Classical Mechanics. 2nd ed.

New York: Springer-Verlag.

Boyd, R. 1983. On the Current Status of Scientific Realism.

In The Philosophy of Science. R. Boyd, P. Gasper, and J.D. Trout, editors. 1991.

Cambridge, MA: MIT Press.

Brown, H.I. 1987. Observation and Objectivity. New York: Oxford University Press.

Churchland, P.M., and C.A. Hooker 1985. Images of Science. Chicago: University Press.

Friedman, M. 1983. Foundations of Space-Time Theories. Princeton: University Press.

Hacking, I. 1982. Experimentation and Scientific Realism.

In Philosophy of Science: The Central Issues. M. Curd and J.A. Cover, editors. 1998.

New York: W.W. Norton.

——. 1985. Do We See through a Microscope? In Churchland and Hooker 1985.

——. 1989. Extragalactic Reality: The Case of Gravitational Lensing.

Philosophy of Science 56:555–81.

Miller, A.I. 1981. Albert Einstein's Special Theory of Relativity. Reading, MA:

Addison-Wesley.

Miller, R.W. 1987. Fact and Method. Princeton: University Press.

Newton-Smith, W.H. 1981. The Rationality of Science. London: Routledge.

Nozick, R. 1998. Invariance and Objectivity. Proceedings and Addresses of the APA

72(2):21–48.

Nye, M.J. 1996. Before Big Science: The Pursuit of Modern Chemistry and

Physics 1800–1940. New York: Simon & Schuster Macmillan.

Shapere, D. 1993. Astronomy and Antirealism. Philosophy of Science 60:134–50.

Stein, H. 1989. Yes, but . . . Some Skeptical Remarks on Realism and Anti-Realism.

Dialectica 43(1–2):47–65.

Suppe, F. 1989. The Semantic Conception of Theories and Scientific Realism.

Urbana: University of Illinois Press.

——. 1997. Science without Induction. In The Cosmos of Science. J. Earman

and J.D. Norton, editors. Pittsburgh: University Press.

Van Fraassen, B.C. 1980. The Scientific Image. Oxford: Clarendon.

——. 1985. Empiricism in Philosophy of Science. In Churchland and Hooker 1985.

——. 1989. Laws and Symmetry. Oxford: Clarendon.

——. 1991. Quantum Mechanics: An Empiricist View. Oxford: Clarendon.

Wehr, M.R., and J.A. Richards 1967. Physics of the Atom. 2nd ed. Reading, MA:

Addison-Wesley.

Wickramasinghe, H.K., 1989. Scanned-Probe Microscopes. Sci. Amer. (Oct):98–105.

Zahar, E. 1989. Einstein's Revolution. LaSalle, IL: Open Court.

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A lovely essay! Well done.

The chances are we shall never meet reality unadorned. We are fifteen orders of magnitude shy of Planck Length using our best and -most expensive- equipment with our most sophisticated theories. It looks like we will run out of money and probably out of wits long before we get Down There. In the mean time we build up a coherent picture (as you so nicely describe) using a progression of theories that fit at the edges. This is probably as good as it is gong to get.

Ba'al Chatzaf

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The most interesting empirical equivalences, to my mind, are those in which the equivalence has been proven mathematically. As Apollonius knew, the apparent motions of moon, sun, or planet about the earth can be modeled equivalently by either of two geometric models, eccenter or epicycle. Their equivalence is geometrically demonstrable. Which of these two models is physically real? I should say, as do many others, that what is invariant between the models is potentially "the undraped figure of nature itself," whereas, the remainder in the models is surely only "the gay-coloured vesture with which we clothe it." The invariant between equivalent and empirically adequate models is closer the physically real.

Again, Schrodinger's wave formulation of quantum mechanics is mathematically equivalent to Heisenberg's matrix formulation. Again we are drawn to the invariant between the formulations as being closer to the unadorned figure of nature.

Dirac's formulation, which is the modern version, was the synthesis of both formulations. It is indeed meaningless to claim that one formulation is the correct one and the other one not if they are mathematically equivalent (one formulation may of course be more practical in certain situations). This also means that it is wrong to say that interpretation A of QM is the correct one (and not interpretation B ) if A and B are mathematically equivalent, and therefore lead to the same predictions. One may prefer a certain interpretation for psychological reasons, but that is indeed analog to "the gay-coloured vesture with which we clothe it". If different interpretations are mathematically and physically equivalent, that means that the interpretation itself is in fact irrelevant. It is at most a crutch we use to try to make sense of rather abstract and counterintuitive theories by giving them some kind of visualization, but the crutch is not the "invariant" of the theory, quite different crutches work equally well. Therefore Feynman's famous dictum: Shut up and calculate!

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Dirac's formulation, which is the modern version, was the synthesis of both formulations. It is indeed meaningless to claim that one formulation is the correct one and the other one not if they are mathematically equivalent (one formulation may of course be more practical in certain situations). This also means that it is wrong to say that interpretation A of QM is the correct one (and not interpretation B ) if A and B are mathematically equivalent, and therefore lead to the same predictions. One may prefer a certain interpretation for psychological reasons, but that is indeed analog to "the gay-coloured vesture with which we clothe it". If different interpretations are mathematically and physically equivalent, that means that the interpretation itself is in fact irrelevant. It is at most a crutch we use to try to make sense of rather abstract and counterintuitive theories by giving them some kind of visualization, but the crutch is not the "invariant" of the theory, quite different crutches work equally well. Therefore Feynman's famous dictum: Shut up and calculate!

Feynman was being his witty outrageous self. I think Feynman's creative processes involved a lot of "right brain" thinking, intuition and visualization (for example Feynman Diagrams). R.P.F. did a lot more than just calculate. If you want calculation, buy or build a computer. If you want new theories and ideas you need a living intellect that is doing more than calculations or formal manipulations of mathematical objects. For Feynman, math was a tool. It was NOT the essence of his theorizing.

There are two aspects to science:

1. Discovery --- questions asked, hypotheses formulated, laws proposed.

2. Justification - predictions derived mathematically and tested empirically.

Both aspects are essential for doing physical science.

The Discovery aspect is not entirely logical. There is a lot of free association and mental roaming going on. An example of this were Einstein's various gedanken scenarios. When A.E. was a sixteen year old lad he imagined what it would be like to race alongside a light wave. That is pure intuitive visualization. He also got his idea for gravitation by imagining that a person in an elevator being accelerated upward would have the same experience as a person in a uniform gravitational field. This is one way of expressing the equivalence principle and it lead to his formulation of General Theory of Relativity as a -geometrical- theory of gravitation, based on the shape of the space-time manifold in the presence of mass, rather than as a force similar to electromagnetic forces.

Ba'al Chatzaf

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Thanks for the compliment and comments, Bob and Dragonfly.

I wrote this essay in 2000. There is an important book on the issue, unknown to me at that time, which I should mention:

Psillos, S. 1999. Scientific Realism: How Science Tracks Truth. Routledge.

Check out also:

da Costa, N., and S. French. 2003. Science and Partial Truth. Oxford.

I have not yet determined to what degrees Rand's views in metaphysics and epistemology favor constructive empiricism or any of the types of scientific realism. We'll see.

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Another book that is important in this regard: Bernard d'Espagnat, Physics and Philosophy, Princeton University Press 2006, which contains an extensive discussion of many different kinds of "realism".

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Dragon:

~ You argue about 'interpretations' which are mathematically equivalent. Not sure what's meant there. Most 'interpretations' of a math-established conclusion may refer back to it, but are not themselves identical to each other. That's why they're considered in the plural: an implied difference re the 'interpretation.'

~ What interpretations (presumably ostensibly 'different'/conflicting) that are m-equiv are you referring to re what math argument? I don't see how conflicting interpretations are equivalent because they stem from the same base.

LLAP

J:D

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Stephen:

~ Thank you for posting this. You chronically establish your depth of understanding and coherency of perspectives on very esoteric yet extremely important subjects. I get mesmerized reading your articles and posts...as I once had reading another, now deceased, 'Stephen.' --- Ok; enough flattery.

~ Can't say what level/type of 'realism' I adhere to, nor sure if I should be all that concerned, 'category'-wise. Yet, the arguments you spell out re the varied areas make me think about changing my reading habit priorities.

Baal:

~ I remember a ('NOVA', I believe) bio on Feynman a while back, and always remember a clip of him discussing his way of approaching scientific probs: "Playing with the ideas." His stress was on, akin to Einstein's imagining 'riding a beam of light', disregarding the established/accepted limitations re subject X, supposing (in terms of an SF writer) 'What if...?' His stress was on the word 'play;' never forgot that.

LLAP

J:D

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Dragon:

~ You argue about 'interpretations' which are mathematically equivalent. Not sure what's meant there. Most 'interpretations' of a math-established conclusion may refer back to it, but are not themselves identical to each other. That's why they're considered in the plural: an implied difference re the 'interpretation.'

~ What interpretations (presumably ostensibly 'different'/conflicting) that are m-equiv are you referring to re what math argument? I don't see how conflicting interpretations are equivalent because they stem from the same base.

An interpretation is a visualization of a theory that makes it easier for us to get an idea what is happening. But some interpretations may be quite different, for example the Copenhagen interpretation (which itself has several variants, but never mind) and the many-worlds interpretation of QM are certainly different, while they lead to exactly the same physics, namely the mathematical formalism of QM. That is what allows us to make predictions with astounding accuracy. That such wildly different interpretations correspond to exactly the same physical theory is a very strong indication that they are themselves not essential, but merely a psychological crutch to get some feeling for the abstract mathematical theory. What makes or breaks a theory is the experimental evidence, but that doesn't tell us anything about a particular interpretation, as a quite different, but mathematically equivalent interpretation gives exactly the same results. They cannot be distinguished experimentally, which means that it is meaningless to call one of them the correct one and the other one the wrong one. After all reality (i.e. the empirical evidence) is the final arbiter, not psychological preferences.

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Dragon:

~ Re your comment...

...some interpretations...[as]...the Copenhagen interpretation...and the many-worlds interpretation of QM are certainly different, while they lead to exactly the same physics, namely the mathematical formalism of QM.

...as 'explaining' how differing interpretations can be considered equivalent, I find your phrasing quite a bit misleading.

~ I don't see these 'interpretations' as what 'lead' to exactly the same physics at all. They 'lead' nowhere (unlike Al's re-'interpretation' of gravity). They were not a starting point all interpreters found the same math formalism from. They were conclusions which follow from such formalism (not the same thing) according to the metaphysics of the interpreters.

~ I think you're putting a cart before the horse here. QM came 1st; its QT's came after.

LLAP

J:D

Edited by John Dailey

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Dragon:

~ Consider Al's 'interpretation' of gravity for a moment. No, not his final 'interpretation' (which he ultimately empirically justified via making it math-formalized, AND found [non-'statistical', can we say?] predictability therefrom), but his consideration OF an alternative (re 'force/action-from-a-distance') to Newton's reluctantly accepted view, in searching for a useable ('psychological', if you will) stepping-stone to gain new knowledge therefrom.

~ I go with Al re QM (not to be confused with the myriad fantasy 'interpretations' of all QTs) being a useful 'methodology', but not an 'interpretation' of it as being an explanatory base. It has probs (as Michio Kaku has spelled out several times and ways) not the least of which is present incompatibility with the 'math-formalism' of Relativity.

~ There's more to the Universe's 'bottom line' than mere QM.

LLAP

J:D

Edited by John Dailey

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~ I don't see these 'interpretations' as what 'lead' to exactly the same physics at all. They 'lead' nowhere (unlike Al's re-'interpretation' of gravity). They were not a starting point all interpreters found the same math formalism from. They were conclusions which follow from such formalism (not the same thing) according to the metaphysics of the interpreters.

If you don't like the world 'lead' you may replace it by 'correspond'. They do not follow from the formalism, however, as that would determine the correctness of one particular interpretation, while we've seen that quite different interpretations can both correspond to exactly the same formalism. Anyway, it doesn't change the point I've made about the meaning of those interpretations.

~ I think you're putting a cart before the horse here. QM came 1st; its QT's came after.

That's a simplistic view. The development of the theory was a continuous interaction between the gradual development of the mathematical formalism and the physical interpretation. What was special about QM is that the simple correspondence between formalism and interpretation, which was intuitively obvious, and that characterized classical physics no longer seemed to work. The old Bohr model of the atom was still based on that classical intuitive correspondence (electrons orbiting the nucleus like planets turning around the sun). It turned out however that this classical interpretation didn't work well and that this notion would have to be given up to create a working theory. So via Schrödingers wavefunctions and Heisenberg's matrix algebra a more abstract formalism was developed, which got its final form by Dirac and von Neumann.

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Dragon:

~ The 'formalisms' (aka 'math formalism') I have no problem accepting as an 'interpretation' informing the development of the...latest...formalism(s?)

~ It's the...latest...conceptual 'interpretations' (AND, your consideration of those as being equivalent) I'm having a...'simplistic'...prob with; I think you're over-simplifying my conundrums here. For instance, other than their derivative source 'formalism' they've followed from (not 'corresponded to', any more than 'lead to') I see nothing worth calling 'equivalent' amongst them. I'd appreciate a spelling out of such, rather than a mere assertion of my showing a 'simplistic' view.

LLAP

J:D

Edited by John Dailey

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~ The 'formalisms' (aka 'math formalism') I have no problem accepting as an 'interpretation' informing the development of the...latest...formalism(s?)

Sorry, I don't understand this sentence.

~ It's the...latest...conceptual 'interpretations' (AND, your consideration of those as being equivalent) I'm having a...'simplistic'...prob with; I think you're over-simplifying my conundrums here. For instance, other than their derivative source 'formalism' they've followed from (not 'corresponded to', any more than 'lead to') I see nothing worth calling 'equivalent' amongst them. I'd appreciate a spelling out of such, rather than a mere assertion of my showing a 'simplistic' view.

If two interpretations cannot empirically be distinguished while they correspond to the same mathematical formalism, they are physically equivalent, as in physics only the empirical results count, these form the check with reality, not the untestable interpretations.

PS. I will be away for a few weeks, with no access to the Internet. So if people have problems or questions, they'll have to be patient. In the meantime Daniel can hold the fort for me. He seems to be the right person to keep the lions at bay.

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There are varieties of scientific realism, but let me begin with the strongest sort. This would be the view that scientific theories, principles, and theoretical entities are factually true or false, that they are the way the physical world is constituted or not, that they are instantiated, as conceived, in the world or not. On this view also, science can come ever closer (even all the way) to ascertaining the truth or falsity of a theory, and so, ever closer to ascertaining a way the world is; by further observations and experiments and their analyses. Even facets of the theory not observable, directly nor indirectly, may be so ascertained of the world, under full-strength realism (Van Fraassen 1980, 7–9; Newton-Smith 1981, 28–29, 37–39; Boyd 1983, 195, 211; Brown 1987, 10–16, 20–22; Miller 1987, 363–67; Suppe 1989, chp. 12).

............the remainder of this lovely article snipped to conserve disk space........................

Stephen, you are clearly the smartest guy posting on this board. You know your stuff. As Long John Silver might say ---- arrrrgggghhhh. Smarrrrt as paint ye arrre-----.

Look, Reality is Real. It is Out There. It is what it IS. What we poor hominid schmucks with the three pound brains get are the Appearences. We have the phenomena, thanks to our sensory systems evolved over millyuns and millyuns of years. Here is the rock bottom fact of our knowing existence: WWSIWWG. What we (see or perceive) is what we get. Everything else is inference which might be correct (in some cases) and incorrect in others. That is the -best- we can do, which all things considered is not all that bad. There is no doubt of it. We are the smartest, baddest apes in The Monkey House.

And what is even more wonderful about our state of incomplete knowledge of the world, as that there is PLENTY of room for improvement. We will take a long time running out of ways to extend our knowledge. We ought never to be bored or blase. There is a veritable treasure house, a horn of plenty for is to dip into, drill into, gather from, fiddle with and just plain enjoy.

Ba'al Chatzaf

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Tracking Truth

Knowledge, Evidence, and Science

Sherrilyn Roush (Oxford 2005)

http://www.oup.com/uk/catalogue/?ci=9780199232932

From the back cover:

Tracking Truth presents a unified treatment of knowledge, evidence, and epistemological realism and anti-realism about scientific theories. A wide range of knowledge-related phenomena, especially but not only in science, strongly favour the idea of tracking as the key to what makes something knowledge. A subject who tracks the truth—an idea first formulated by Robert Nozick—has the ability to follow the truth through time and changing circumstances. Epistemologists rightly concluded that Nozick's theory was not viable, but a simple revision of that view is not only viable but superior to other current views. In this new tracking account of knowledge, in contrast to the old view, knowledge has the property of closure under known implication, and troublesome counterfactuals are replaced with well-defined conditional probability statements. Of particular interest are the new view's treatment of skepticism, reflective knowledge, lottery propositions, knowledge of logical truth, and the question why knowledge is power in the Baconian sense.

Ideally, evidence indicates a hypothesis and discriminates it from other possible hypotheses. This is the idea behind a tracking view of evidence, and Sherrilyn Roush provides a defense of a confirmation theory based on the Likelihood Ratio. The accounts of knowledge and evidence she offers provide a deep and seamless explanation of why having better evidence makes one more likely to have knowledge. Roush approaches the question of epistemological realism about scientific theories through the question what is required for evidence, and rejects both traditional realist and traditional anti-realist positions in favour of a new position which evaluates realist claims in a piecemeal fashion according to a general standard of evidence. The results show that while anti-realists were immodest in declaring a priori what science could not do, realists were excessively sanguine about how far our actual evidence has so far taken us.

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Gauging What’s Real

The Conceptual Foundations of Gauge Theories

Richard Healey (Oxford 2007)

http://www.oup.com/uk/catalogue/?ci=9780199287963

From the back cover:

Gauge theories have provided our most successful representations of the fundamental forces of nature. How, though, do such representations work? Interpretations of gauge theory aim to answer this question. Through understanding how a gauge theory's representations work, we are able to say what kind of world our gauge theories reveal to us.

A gauge theory's representations are mathematical structures. These may be transformed among themselves while certain features remain the same. Do the representations related by such a gauge transformation merely offer alternative ways of representing the very same situation? If so, then gauge symmetry is a purely formal property since it reflects no corresponding symmetry in nature.

Gauging What's Real describes the representations provided by gauge theories in both classical and quantum physics. Richard Healey defends the thesis that gauge transformations are purely formal symmetries of almost all the classes of representations provided by each of our theories of fundamental forces. He argues that evidence for classical gauge theories of forces (other than gravity) gives us reason to believe that loops rather than points are the locations of fundamental properties. In addition to exploring the prospects of extending this conclusion to the quantum gauge theories of the Standard Model of elementary particle physics, Healey assesses the difficulties faced by attempts to base such ontological conclusions on the success of these theories.

From the Table of Contents:

1. What is a Gauge Theory?

2. The Aharonov-Bohm Effect

3. Classical Gauge Theories

4. Interpreting Classical Gauge Theories

4.1 The No Gauge-Potential Properties View

4.2 The Localized Gauge-Potential Properties View

4.3 The Non-Localized Gauge-Potential Properties View

4.4 A Holonomy Interpretation

4.4.1 Epistemological Considerations

4.4.2 Objections Considered

4.4.3 Semantic Considerations

4.5 Metaphysical Implications: Non-Separability and Holism

5. Quantized Yang-Mills Gauge Theories

6. The Empirical Import of Gauge Symmetry

6.1 Two Kinds of Symmetry

6.2 Observing Gauge Symmetry?

6.3 The Gauge Argument

6.4 Ghost Fields

6.5 Spontaneous Symmetry-Breaking

6.6 The Theta-Vacuum

6.7 Anomalies

7. Loop Representations

8. Interpreting Quantized Yang-Mills Gauge Theories

8.1 Auyang’s Event Ontology

8.2 Problems of Interpreting a Quantum Field Theory

Edited by Stephen Boydstun

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"... as confidently as some Chymists and other modern innovators in philosophy are wont to object against the peripetitics that from the mixture of their four Elements there could arise an inconsiderable variety of compound bodies; yet if the Aristotleans were as versed in the works of Nature as they are in the writings of their master, the proposed objection would not so calmly triumph, as for want of experiments they are fain to suffer to do." -- Robert Boyle, The Skeptical Chymist, 1661.

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"... as confidently as some Chymists and other modern innovators in philosophy are wont to object against the peripetitics that from the mixture of their four Elements there could arise an inconsiderable variety of compound bodies; yet if the Aristotleans were as versed in the works of Nature as they are in the writings of their master, the proposed objection would not so calmly triumph, as for want of experiments they are fain to suffer to do." -- Robert Boyle, The Skeptical Chymist, 1661.

Thank you. That quote indicates that as far back as Robert Boyle, Aristotle's disinclination to check his results (a fault shared by his followers as well) raised some hackles.

Ba'al Chatzaf

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I wonder if Aristotle felt experimentation to be beneath him. Like trade. I have nothing but conjecture.

--Brant

I don't think that was the reason. Aristotle spent a lot of his time looking at specimens and examining them carefully (in some cases). He did as well as anyone could given that there were no magnifying glasses or microscopes in his time. Aristotle believed that if humans examined a sufficient number of particulars they would be lead to general necessary truths. This was his method for -discovering- (not proving!) the basic axioms (necessary true general statements). Once the axioms were achieved (so he thought) all one needed to do was to deduce the consequences, by sound logic. Aristotle thought he had established all the necessary truths and the rest was merely a matter of cranking out the correct consequences.

In short, Aristotle did not believe empirical input was necessary beyond what was needed for discovering the True Ideas. This differs considerably from the modern attitude that all theories are provisional at best and new facts can be discovered which might falsify them. Hence theories must be constantly checked against newly discovered facts. No modern scientist believes any of his theories can be established as certain and true after a finite set of corroberations by experiment or observation. The potential for falsification always exists.

Aristotle differed somewhat from his teacher Plato in the matter of forms and the nature of universals, but both believed that empirical knowledge could serve to "remind us" of the Truth Ideas. The truth lay in the Forms and the Ends (or Completions) of the Forms, i.e. Telos. We would first have to see the shadows on the walls (to use Plato's metaphor) before we could be lead to the truth behind the shadows. Both Aristotle and Plato believed that. We could never get to the True Ideas without sensory input. The error would lie in identifying truth with mere perceptions. Plato believed True Ideas were beyond matter, Aristotle believed that True Ideas were embedded in Matter as Forms, not separated in a totally distinct universe or world.

There is an interesting book that I am now reading (it is a tough read and it is written for scholars). The book is -Aristotle and Other Platonists- by LLoyd P. Gerson, Cornell University Press, 2005. Gerson shows that Aristotle was -never- an anti-Platonist despite some text (see Nichomachean Ethics, for example) where Aristotle distances himself somewhat from his Teacher. It was later scholars who tried to see Aristotle as being radically opposed to Plato. He was not. Gerson makes an interesting case.

Ba'al Chatzaf

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Sweeping, Informed, Bravo!

A Metaphysics for Scientific Realism:

Knowing the Unobservable

Anjan Chakravartty (Cambridge University Press 2007)

From the Table of Contents:

Part I - Scientific realism today

1 Realism and antirealism; metaphysics and empiricism

1.1 The trouble with common sense

1.2 A conceptual taxonomy

1.3 Metaphysics, empiricism, and scientific knowledge

1.4 The rise of stance empiricism

1.5 The fall of the critique of metaphysics

2 Selective skepticism: entity realism, structural realism, semirealism

2.1 The entities are not alone

2.2 Lessons from epistemic structuralism

2.3 Semirealism (or: how to be a sophisticated realist)

2.4 Optimistic and pessimistic inductions on past science

2.5 The minimal interpretation of structure

3 Properties, particulars, and concrete structures

3.1 Inventory: what realists know

3.2 Mutually entailed particulars and structures

3.3 Ontic structuralism: farewell to objects?

3.4 Ontological theory change

3.5 Return of the motley particulars

Part II - Metaphysical foundations

4 Causal realism and causal processes

4.1 Causal connections and de re necessity

4.2 Is causal realism incoherent?

4.3 A first answer: relations between events

4.4 A better answer: causal processes

4.5 Processes for empiricists

5 Dispositions, property identity, and laws of nature

5.1 The causal property identity thesis

5.2 Property naming and necessity

5.3 Objections: epistemic and metaphysical

5.4 Vacuous laws and the ontology of causal properties

5.5 Causal laws, ceteris paribus

6 Sociability: natural and scientific kinds

6.1 Law statements and the role of kinds

6.2 Essences and clusters: two kinds of kinds

6.3 Clusters and biological species concepts

6.4 Sociability (or: how to make kinds with properties)

6.5 Beyond objectivity, subjectivity, and promiscuity

Part III - Theory meets world

7 Representing and describing: theories and models

7.1 Descriptions, and non-linguistic representations

7.2 Representing via abstraction and idealization

7.3 Extracting information from models

7.4 The inescapability of correspondence

7.5 Approximation and geometrical structures

8 Approximate truths about approximate truth

8.1 Knowledge in the absence of truth simpliciter

8.2 Measuring “truth-likeness”

8.3 Truth as a comparator for art and science

8.4 Depiction versus denotation; description versus reference

8.5 Products versus production; theories and models versus practice

Edited by Stephen Boydstun

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Sweeping, Informed, Bravo!

A Metaphysics for Scientific Realism:

Knowing the Unobservable

Anjan Chakravartty (Cambridge University Press 2007)

.....snipped to conserve band width.....

Interesting looking book.

By the way how does one observe Aether since it cannot be observed? The answer is: one doesn't. One discards the concept.

That is why successful physics is phenomenal rather than ontological.

What You See is What You Get.

The only unobserved things we have in our science are hypothetical causes which are known only by their observable effects.

Have you seen an atom lately? How about a quark? What the folks at the high energy machines see are resonances.

Ba'al Chatzaf

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Why Science Needs Metaphysics:

A Plea for Structural Realism

Elie Zahar (Open Court 2007)

http://www.opencourtbooks.com/books_n/why_science.htm

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"Explaining the Unobserved---Why Quantum Mechanics Ain't Only about Information"

Amit Hagar and Meir Hemmo 2006

Foundations of Physics 36(9)

http://mypage.iu.edu/~hagara/OnBub.pdf

The distinction between principle-theories and constructive theories is from Einstein.

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