There Are No Quarks : Can You Prove Me Wrong? (Page 10)

CoIin: More good sense from Quine:-

Quine's doctrine of scientific and philosophical naturalism denies any qualitative division between philosophy, science, language, and mathematics. We're all in the same boat - Neurath's boat - which must be constantly repaired and maintained at sea as new discoveries are made. We can never come into port. We are adrift, anchored to no "a priori" unshakable truths of the kind other philosophers are wont to speak.

And that means ANYTHING we presently hold to be true is potentially subject to revision. Yes, even the most fundamental laws of physics. Yes, even "all bachelors are unmarried men". Yes, even 2+2=4

It is to scientists we must turn for our knowledge of what exists. But that doesn't imply we must take everything scientists tell us to be true.




"In any event, we are now seeing ontology as more utterly a human option than we used to. We are drawn to Lauener's pragmatism. Must we then conclude that true reality is beyond our ken? No, that would be to forsake naturalism. Rather, the notion of reality is itself part of the apparatus; and sticks, stones, atoms, quarks, numbers, and classes are all utterly real denizens of an ultimate real world, except insofar as our present science may prove false on further testing.

[...]

Still, our concept of truth strains at its naturalistic moorings in another way. We naturalists say that science is the highest path to truth, but still we do not say that everything on which scientists agree is true. Nor do we say that something that was true became false when scientists changed their minds. What we say is that they and we THOUGHT it was true, but it wasn't. We have scientists pursuing truth, not decreeing it. Truth thus stands forth as an ideal of pure reason, in Kant's apt phrase, and transcendent indeed. On this score I am again with Lauener."

(from "Naturalism; or, Living within One's Means" )

DEEP_acheleg: there seems to be many experimental observations on the subatomic level of phenomena which seem to align with the predictions of quark interactions; even though, according to those theories NO SINGLE QUARK ever exists. but, that is a technicality.

many sciences, even economics, rely on models to make predictions regarding the system being modeled. many models work good enough, although they are rarely to never assumed to be a concise portrayal of reality.

even if the predictions seem to consistently work with a particular model for a good, long time, eventually, contradictions between the he hypothetical and the physical will likely become obvious.

for a millennium, the geocentric model of the heavens used epicycles and spheres to predict the movements of stars and planets. Copernicus realized that this model could be greatly simplified by placing the sun in the center of the heavens; however, the known physics and logic of that day strongly suggested that the centripetal force (whatever basic ideas they had for inertia, conservation of momentum, etc...) at the 1070mph the earth would need to rotate within 24 hours would make such a heliocentric model seem quite unrealistic.


not to rehash another thread, but Galileo's controversial reception was to be well expected. without a notion of gravity, the "orbiting" moons of jupiter did not fit with the ptolemaic model of the day, nor could they be explained logically. it would take a revolution in science to make a new heliocentric model which the commoners could accept as reflective of reality, by incorporating concept of "universal gravitation" gravity was shown to be a physical, predictable force, related to mass and distance, and the refinement to ellipses of kelpers orbits were shown by newton to be due to the "inverse square to the radius" formula for local-scale gravity.

is our present understanding of gravity realistically accurate- hardly; yet, it will take another revolution in physics until we will have no more need for spectacular rockets to escape the "gravity" of the earth..

DEEP_acheleg: photons-now there is a good one... light is made of waves, divided into bands of wavelengths- yet, photons are the experimental observations of light in a matter which is consistent with light being made up of particles, and not waves. is it a wave, is it a particle? ask richard feynman...

CoIin: Nobel Prize-winning physicist Steven Weinberg, for reasons best known to himself, is notoriously hostile to philosophy.

Hostile or not, though, when a scientist takes a break from doing science and REFLECTS UPON HOW SCIENCE IS DONE, then he or she is as guilty as anyone else of perpetrating philosophy. In the following passage, taken from a 1998 review of Thomas Kuhn's work, Weinberg commits the cardinal sin of critical analysis - he philosophizes!

What's even more remarkable about this excerpt is that anti-philosophical belligerence and unapologetic realism notwithstanding, IT MIGHT AS WELL HAVE BEEN WRITTEN BY MYSELF!

Here's Weinberg:-

"It is important to keep straight what does and does not change in scientific revolutions, a distinction that is not made in [The Structure of Scientific Revolutions]. There is a "hard" part of modern physical theories ("hard" meaning not difficult, but durable, like bones in paleontology or potsherds in archaeology) that usually consists of the equations themselves, together with some understandings about what the symbols mean operationally and about the sorts of phenomena to which they apply. Then there is a "soft" part; it is the vision of reality that we use to explain to ourselves why the equations work. The soft part does change: we no longer believe in Maxwell's ether, and we know there is more to nature than Newton's particles and forces.

The changes in the soft part of scientific theories also produce changes in our understanding of the conditions under which the hard part is a good approximation. But after our theories reach their mature forms, their hard parts represent permanent accomplishments."

(from "The Revolution That Didn't Happen" )


Weinberg's "hard part" corresponds to my observable reality, and his "soft part" to my unobservable reality.

Scientific theories allow us to systematize, predict, and thus, in many cases, to intervene in observable phenomena. They allow us, among other things, to navigate the oceans, build computers, travel into space, and treat illnesses.

Science excels at this. But scientific theories, by and large, have another tale to tell, viz., the story of unobservable processes, entities, and mechanisms happening backstage (forces, fields, quarks, photons, phlogiston, electrons, crystalline spheres, ether, four humours, dark matter, dark energy, space, time, etc) -- THAT WE NEVER SEE -- explaining that which WE DO SEE frontstage.

And make no mistake, it's backstage where that elusive beast -- Truth -- is rumored to lurk in the shadows. Although I suspect he may not fully appreciate the implications of his own words, Weinberg is effectively agreeing with all I've said in this thread, and that is, theories WORK, and they continue to work even when later revealed to be untrue. This is Weinberg's largely inflexible "hard part". His hard part doesn't turn flaccid when one theory is replaced by another; equations and theories that worked before don't stop working. However, insofar as Weinberg's protean "soft part" -- the TRUTH -- keeps changing, we have no basis to infer that science is approaching an accurate representation of reality.

Through radical theory change in science, sailors keep sailing, gadgets keep gadging, rockets keep flying, and doctors keep curing -- in fact, they do these things better than they did before -- nonetheless the stories we're told of backstage goings on purportedly explaining how these achievements are possible alter to the point of being unrecognizable from one another.

And to those who dismiss the antirealist's observable-unobservable distinction as spurious, you might consider asking Mr Weinberg how he discriminates between his hard part and soft part.

CoIin: Everyone agrees, I take it, that there is a scientific scrapheap consisting of entities once postulated in theories and supposed to be real, only to be subsequently abandoned as non-existent.

Phlogiston, caloric and the ether are three standard and uncontroversial examples. Even the staunchest scientific apologist will concede that these entities are illusory, they do not "refer"; that is, there is nothing in reality corresponding to scientific descriptions of phlogiston, caloric or the ether -- "We were just plain wrong. There's no such thing."

But what role does language play in all this? Might it be that arbitrary choices to retain or discard a particular name engender a misleading impression that the scrapheap is much smaller than it actually is?

Consider, for example, the various models of the atom that have been proposed in the modern era. There is nothing in reality (as far as we now believe) corresponding to 19th century models of the atom. And there is nothing in reality that corresponds to phlogiston. But atoms survive while phlogiston was ignominiously dumped.

Had nineteenth century atoms been called "natoms" in contrast with shiny new 21st century "atoms" then that scrapheap would reach just a lil bit higher.

It's not bleedin' fair, I tell ya!



"The second irony I had in mind is the circumstance that Hilary Putnam, writing as an exponent for realism, has used the notion of ether, in contrast with that of atoms, as an example of a scientific term that failed to "refer" -- there is no such thing as the ether, whereas there are atoms (note that this endorses the discrimination committed by Poincaré ); and that Larry Laudan has exploited this as one example among others in an argument AGAINST realism -- namely, against the view that there is any strong connection between "instrumental success" (here, of the wave theory of light and of Maxwell's electrodynamics, both of which posited an ether) and "real reference". For my part, I throw up my hands at this: Why should we say that the old term "ether" failed to "refer"? -- and that the old term "atom" did "refer"? Why, that is, except for the superficial reason that the word "atom" is still used in textbooks, the word "ether" not? -- It would be possible to do a lengthy dialectical number on this; but in brief: our own physics teaches us that there is NOTHING that has all the properties posited by nineteenth-century physicists for the ether OR for atoms, but that, on the other hand, in BOTH instances, rather important parts of the nineteenth-century theories are correct. For instance, so far as Poincare's conviction that momentum conservation must hold among the "particles" taken by themselves is concerned, it is established now beyond a doubt that ordinary bodies do exchange momentum with "the ether" -- i.e. with the electromagnetic field; and even that this field has to be regarded as the seat of a distribution of mass, and as participating in gravitational interactions. The two cases -- that of the ether and that of atoms -- are, in my view, so similar, that the radical distinction made between them by the referential realists confirms in me the antecedent suspicion that this concern for reference -- and associated with it, another Quinean motif, the concern for what is called the "ontology" of theories -- is a distinction from what really matters."

( "Yes, but... Some Skeptical Remarks on Realism and Anti-Realism" - Howard Stein)

http://strangebeautiful.com/other-texts/stein-yes-but-skept-remarks-real-antireal.pdf

CoIin: It is sometimes the case, due to disparity in language usage or vagaries of definition, that those who take themselves to be in disagreement are, in fact, not.

What do we mean when we speak of a theory being "true"?

Consider two physical theories, T1 and T2:-

T1 posits the existence of unobservable entities known as pluons and quapps. In addition, T1 makes certain claims about the nature of time and space.

T2 posits the existence of unobservable entities known as gruons and phorks. T2 also makes claims about the nature of time and space.

Gruons and phorks are not simply pluons and quapps under a different name; the properties attributed to each are distinct. Similarly, the claims both theories make regarding space and time are logically incompatible with one another. (E.g., T1 claims an infinite universe and uniform space; T2 claims a finite universe and non-uniform space).

Let's further suppose that, within their own domain of inquiry, T1 and T2 are "empirically adequate" in every respect, which is to say they are both in perfect agreement with all actual and all possible observation and experiment. The two theories "work" perfectly; they yield only correct predictions. At the practical level neither will ever let you down; one is as reliable -- PERFECTLY reliable -- as the other.

But can they both be "true"?

Well, what would YOU say, dear reader? (Bourbaki? ) Is it sufficient that a theory be in perfect agreement with observational reality for us to assign it the epithet "true"? Or must it also get unobservable reality right? After all, if the metaphysical (by which here I mean "unobservable" ) claims of T1 are right then those of T2 must be wrong. If pluons exist then gruons do not, and so forth, mutatis mutandis, for the other ontological claims.

And, while we're at it, how would we ever KNOW if one or other of the theories had got the unobservable part of reality right?

For the typical antirealist or instrumentalist, the aim of science is simply to accurately describe and systematize observable reality. T1 and T2 both do this. Whether quapps and phorks REALLY exist is a matter of little interest, and for some antirealists, questions of this type are dismissed as a category error - a bit like asking whether an imperative such as "Come in! " is true or false.

Talk of pluons and quapps, gruons and phorks is an invitation to perpetrate metaphysics - a place where respectable science has no right to be. Echoing antirealist exhortations that the truth claims of science should be limited to the EMPIRICAL, Pierre Duhem continues:-

"Thus a true theory is not a theory which gives an explanation of physical appearances in conformity with reality; it is a theory which represents in a satisfactory manner a group of experimental laws. A false theory is not an attempt at an explanation based on assumptions contrary to reality; it is a group of propositions which do not agree with the experimental laws. AGREEMENT WITH EXPERIMENT IS THE SOLE CRITERION OF TRUTH FOR A PHYSICAL THEORY."

(from "The Aim and Structure of Physical Theory" )

Bourbaki: "But can they both be "true"?"
This is an interesting question.

This relates to a brief discussion we had about interpolation, extrapolation, and limiting cases of general theory (e.g Newtonian Mechanics and General Relativity). (Forgive me for not citing the page.) I'll touch on that later on.

Strictly speaking, we recognize the fact that our theories merely offer (hopefully) increasingly accurate approximations of what we observe in nature. Nonetheless, it's entirely possible for two theories with different domains of inquiry to be consistent with empirical evidence yet mutually inconsistent. To proceed, I must elaborate on what the word "true" will mean when I use it. I will not define it (because I don't think it can be given a definition both accurate and satisfying), but I will give a necessary condition for a theory to be "true": consistency. In science (perhaps tacitly so), consistency is likely the most important condition a theory is required to uphold. Though this is not violated by either T1 or T2 separately, their mutual inconsistency assures us they cannot - in their current form at least - both be part of a more general, more encompassing theory. This is a big problem and in this (somewhat more precise) sense they cannot both be true. To make the relationship with extrapolating from empirical evidence more explicit , let's refer to the unification T1 and T2 by Γ. So given Γ we wish to extrapolate, but Γ is inconsistent, and it can be shown that starting from an inconsistent body of information, any statement can be given any truth value. This is a useless theory from most points of view.

At a more practical level, this may not be important to people interested in a specific domain of inquiry. To them, the most important things are (usually) the logical consistency of T1, its consistency with evidence, and its ability to accurately predict results of relevant experiments. But these people are not typically concerned with whether both T1 and T2 are "true".

Bourbaki: I'd also like to point out (what appears to me) a blatant logical fallacy in the last excerpt.

"A false theory [...] is a group of propositions which do not agree with the experimental laws. AGREEMENT WITH EXPERIMENT IS THE SOLE CRITERION OF TRUTH FOR A PHYSICAL THEORY."

The first part of the sentence says that inconsistency with empirical data is a sufficient condition for a theory to be false. The second part of the sentence says that a theory is false *if and only if* it is inconsistent with empirical data.

The two are obviously vastly different.

CoIin: Bourbaki - Two points.

1. First, I'm afraid I may have misled you through careless wording. You wrote ...

"Nonetheless, it's entirely possible for two theories with DIFFERENT domains of inquiry to be consistent with empirical evidence ... " [my caps]

... which I assume was in response to my ...

"Let's further suppose that, within their own domain of inquiry, T1 and T2 are "empirically adequate" in every respect ..."

What I'm clumsily trying to say in the sentence above is that T1 and T2's domain of inquiry is IDENTICAL. They are theories about the same phenomenon or class of phenomena. In other words they are RIVALS. In other words, this is our old pal, the underdetermination of theories by data. T1 and T2 are not only rivals, but they are INDISTINGUISHABLE rivals; no empirical evidence can tell between them.

They might both be theories about heat or light or galaxies or anything else. Now if T1 posits pluons, while T2 posits gruons, as the underlying (unobservable) cause of, say, optical phenomena, then from a realist perspective both theories cannot possibly be true; if pluons are the cause then gruons cannot be.

Am I right in thinking I set you on the wrong path? Apologies if so.


2. re your second post. I'm confused. I suspect a typo may be the cause. You said:-

"The first part of the sentence says that inconsistency with empirical data is a sufficient condition for a theory to be false. The second part of the sentence say that a theory is FALSE *if and only if* it is consistent with empirical data."

Surely the word that I've capitalized should read "true" and not "false"? Is this indeed a typo? If we fix it, is there still a problem?



Finally, yes, I think what you say about consistency must be correct. No matter which of the two interpretations of "true" we've been examining [i.e. (i) accurate at the observable level, or (ii) accurate at BOTH the observable and unobservable level] is adopted, it's hard to see how a theory that contradicts itself could ever be said to be "true".

Bourbaki: Quick reply - I have edited my last post to correct the typo.

CoIin: Just to be as clear as possible....

The key question in my post before last was:-

"But can they [T1 and T2] both be "true"?"

The point I was trying to make is that our answer to this question depends on the definition of "true" we adopt. If, for example, we adopt Pierre Duhem's definition above whereby a theory being true consists only in the theory being 100% "empirically adequate", that is, in complete agreement with all possible observation and experiment, then the answer to the question is clearly YES - both T1 and T2 are true.

The next issue, then, is OUGHT we to adopt this definition?

The antirealist cares little for any behind-the-scenes narrative which purportedly explains what we do see frontstage. The antirealist may gladly embrace Duhem's definition of "true" (Let's call this "true1" ). Therefore, for the antirealist, both T1 and T2 are true (= true1).

On the other hand, insofar as the realist wants more than just a theory that WORKS, she's bound to reject Duhem's definition. For a theory to be true, on her account, is not merely that it be in agreement with observation and experiment (i.e. empirically adequate); to be true means -- in addition to empirical adequacy -- that all the entities and mechanisms postulated by the theory do actually exist and operate as described. (Let's call this "true2" ). The realist must concede that T1 and T2 are both true if truth be construed as true1, but true1 is not what the realist calls "true"; true2 is. Thus, T1 and T2 cannot both be true (= true2).

In real world science, of course, genuine cases of strong underdetermination like our T1 vs T2 example where both theories are empirically indistinguishable -- no observation or experiment can choose between them -- are rare if not entirely unheard of.

But before I get accused of more head-in-the-clouds philosophical crap ( ), the point is this: If it can be demonstrated (and this is still controversial) that two, or even a multitude, of theories can be constructed which are logically incompatible with, yet empirically indistinguishable from, one another -- just as T1 and T2 are -- THEN WE HAVE NO GOOD REASON FOR THINKING THAT ANY PARTICULAR SCIENTIFIC THEORY IS TRUE (i.e. true2)

This is the antirealist counterattack to the commonly heard (Wireclub included) "Miracle Argument" for scientific realism that I sketched on page 1.

The Miracle Argument for scientific realism holds that it would be a miracle if science had attained the success it has (rockets to the Moon, gadgets that work, etc, etc.) unless its best theories were true2 or approximately so. We are, therefore, quite justified in committing ourselves to a belief in the unobservable entities (quarks et al) posited therein.

The antirealist response is to turn this argument on its head. If it is indeed the case that an indefinite number of theories are compatible with the very same body of data/evidence, then it would be a miracle if the one scientists have actually hit on is the TRUE (= true2) one

Bourbaki: Personally, I think no empirically indistinguishable theories exist. It seems that by virtue of their being different one can construct an experiment to test aspects unique to each of them.

CoIin: Fair dinkum, sport. As I said earlier, it's controversial.

On the other hand, examples of rival theories in science which are underdetermined by all the AVAILABLE evidence are relatively common. Consider the case of the Ptolemaic model vs the Copernican model of the cosmos circa 1600.

What we've been examining, though, are rival theories (T1 and T2) which are underdetermined by all POSSIBLE evidence. This remains speculative. Theories can be artificially constructed which are claimed to be empirically equivalent (but logically incompatible) with current scientific theories. The realists, as you might imagine, are signally unimpressed.

The masochists out there might enjoy Andre Kukla's "Studies in Scientific Realism" for an impartial (I think) and in-depth examination of the arguments on both sides.

CoIin: What Is This Thing Called Non-Empirical Evidence? (and why should it make a fool of me? )
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"Personally, I think no empirically indistinguishable theories exist. It seems that by virtue of their being different one can construct an experiment to test aspects unique to each of them." - Bourbaki

You may well be right, old chum, but let's assume for the sake of argument that you're not: We have before us not only two theories, but a plurality [T1, T2, ... Tn], all of which are mutually incompatible but empirically indistinguishable, i.e. they all rule in and rule out precisely the same observations. No experiment can tell between them.

Well, what do we do now?

Where the lugubrious realist sees a problem, the lighthearted antirealist sees an embarrassment of riches. For her, one theory is epistemically as good as another - they're all equally true! (i.e. true1) Presumably the antirealist would recommend on purely pragmatic grounds that we adopt the simplest theory (and which one is simplest may depend on the particular application ).

Meanwhile, the realist, and that includes yourself I suspect, seeks some way to break the deadlock. He wants to know which one of the candidate theories is TRUE (= true2). But how is the impasse to be be overcome granting, as we have, that empirical evidence is inadequate to the task?

How about non-empirical evidence?

Well, is there such a thing? And if there is, what could it possibly be?

Simplicity was mentioned earlier, but only as a pragmatic consideration. Could it be, though, that simplicity, over and above practical concerns, also gives us warrant to infer to a theory's TRUTH? It seems clear from the writings of certain prominent realists, notably Einstein, that they believe precisely this.

What say you, Bourbaki?

(Of course, we'd still face the difficulty of providing a satisfactory characterization of simplicity - no easy task!)

Or, how about our next contestant in the Miss Non-Empirical Evidence Pageant : explanation.

The much vaunted (by realists) principle of Inference to the Best Explanation (IBE) stipulates that given an array of rival hypotheses, all of which are compatible with the evidence, we are warranted in inferring to the truth of that hypothesis which offers the best explanation.

It's clear, even just from scanning the posts of other Wireclub members in the Science Forum, that IBE is implicitly accepted by most. For example, we'll read comments like:-

"Current evolutionary theory provides the best explanation for various biological phenomena, the fossil record, and so forth, therefore we have good reason to think it must be true, or approximately so."

Intuitive it undeniably is, but on reflection, why should we think that a theory providing a good explanation constitutes evidence for its TRUTH? What kind of evidence is an EXPLANATION? What IS a good explanation anyway? And doesn't all this talk of "explanatory goodness" have a kind of icky, mushy, unscientific, SUBJECTIVE flavor to it.

Evidently our work is not yet done. Don't stray too far now.

Bourbaki: I'm reluctant to accept the premise, even if only for the sake of argument, but I shall do so.
Certainly, simplicity is an appealing criterion. Obviously it cannot be objectively justified as one, but I can think of several extremely strong arguments in favor of it, the weakest of which is the fact Einstein said so himself. I will present two such arguments. The first is dry and logical. A simpler theory is less prone to imprecision and contradiction. Furthermore it is more naturally generalized and its framework less disturbed by small perturbations. The second is more personal. A simpler theory fits with the apparent minimalism observed in nature. The idea behind Occam's razor - I think - is not rooted in mere pragmatism; it involves a deep belief that "truth" (whatever that means) takes the simplest possible form.
I leave this brief for now.

quarks: *sits on beach polishing quarks*

quarks: sorry Colin if my not funny joke killed your wonderful thread ) :

x_x

CoIin: Not at all.

It's just that after months of fighting off heavyweights, hoodlums, hooligans, and harridans, I'm taken aback at being disarmed so effortlessly.

Who would've thought that these dang quarks were lying on the beach all this time.

CoIin: @ Bourbaki

A reminder of what you said above:-

"Personally, I think no empirically indistinguishable theories exist. It seems that by virtue of their being different one can construct an experiment to test aspects unique to each of them."


Here's an example to ponder then. Consider the following two hypotheses/theories/laws:-

H1 : All emeralds are green
H2 : All emeralds are grue


I assume we all know what green is. Those benighted souls ( ) unfamiliar with "grue" may check out my long post beginning "I can't sleep ... " around the middle of the page in the link below:-

Topic: Philosophy

Now, just to be very clear, Nelson Goodman, who is to grue what Dr Frankenstein is to his own monster, is not suggesting that the grue hypothesis ought to be taken seriously by scientists as a description of nature. He's making a logical point, and that point is that two theories can be confirmed to precisely the same degree by precisely the same evidence. The two theories, in other words, are underdetermined by the evidence.

Prior to the year 2050 (or any other year you care to name), what empirical evidence could possibly tell between H1 and H2? Apparently none.

Well, then, if both theories are equally well confirmed, why do scientists (and everyone else) choose H1 over H2?

Presumably due to NON-EMPIRICAL factors, like those we discussed above (simplicity, explanatory goodness, etc).

Oh yeah? Like what?

Like grue being very silly.


Bourbaki, what do you say? Does this example -- an admittedly artificially constructed example -- count?

CoIin: And this intriguing passage from Larry Laudan that I'm not competent to comment further on:-

"Yet it is notorious that methodological rules usually underdetermine a choice among factual claims in the sense that, although the rules plus the available evidence will exclude many factual claims or hypotheses, a plethora of possible hypotheses often remains methodologically admissible. Among the admissible hypotheses may be some that are evidentially equivalent, in that no conceivable evidence could ever discriminate among them. It is often said, for instance, that certain versions of wave and matrix mechanics are observationally equivalent. In such circumstance, it is clear that no observations could ever decisively choose between them."

DEEP_acheleg: here is my proof of quark. i shall have to read the last brilliant 6 pages of this thread after work....

slasian: If the question at hand is truth...

Constructive empiricists seem to think that we merely need the observable phenomena to be true and don't need a theory to accurately describe the unobservable phenomena, this is a valid reasoning for a lot of scientific purposes. For example a mechanical engineer doesn't need to have an exact model of what a thermodynamic heat flow looks like, he 'just' needs to predict the exact behavior from the heat flow for practical purposes. With this reasoning many disciplines use empirical adequate theories to create and enhance existing technologies.

Hence, in Colin's case, quarks might sound the unobservable part of nature, yet there is a theory that suggests there is no such thing as unobservable phenomenon but unobserved observables. The best example is the case of Dinosaurs. Since the last dinosaurs disappeared from the face of earth 65 million years ago in the Cretaceous-Tertiary (K-T), it is obvious that dinosaurs are unobservable. Yet we have the bones of those things and we can reach to the truth thru the observation of the bones. Hence, we can say that dinosaurs are unobserved observables.

Now Quarks, are of course 'unobservable', yet we can observe them through the energy annihilation of electrons and positrons and the color effect. We can say that we have two observable factors "energy" and "color". Though I had proved Colin's... the most certain truth is that the distinction between observables and unobservables is not clear.

In my opinion, the main problem manifests itself with the scientific disciplines that concern themselves with the accumulation of knowledge. For this I take the example of theoretical physics. Lots of research projects start out of curiosity to an unknown phenomena, unfortunately not for their practical usefulness. Subjects like dark energy & dark matter have almost no practical application at this point in time, but the reason we research it is to satisfy our thirst for knowledge. With these kind of research projects it is not only the aim to find empirical adequacy, but to find the true nature of these phenomena as well.

Since such kind of scientific theory's had never been actually put to problem solving, which in return would have generated a valid, experimented and practical knowledge, the nature of the their output is always in question.

How justified are we in believing in such kinds of scientific statements?

There has always been an alternative theory or anomalous phenomenon that disproves or challenge the belief in such kind of theories. Philosophers of science call this the 'underdetermination of theory by evidence'. In the presence of more than one possible scientific theories, the experiment at hand may not be sufficient to determine the choice of one scientific theory.

I think Pierre Duhem’s answer is what Colin (or I my self) couldn't swallow. Dunham tells us that in such cases, especially when it is difficult to determine which theory to choices, scientists typically follow their ‘good sense’ in making decisions.

At this point, we will say hey wait a minute, didn't a sheik or a tribal medicine man follow his 'good sense'? Isn't science supposed to be based on empirical data?

As a result, Colin's statement that there are no quarks is logically valid.

For me the priority of science should focus on problem solving. This would have resolved the current argy-bargy in philosophical science and especially on the question that, "Are there good reasons to think that scientific theories should be true, rather than “merely” empirically adequate?"

Do we have empirically adequate data on quarks?(proved objectively as if quarks are observable phenomenon and our science should have the means to directly observe these things beyond any doubt or interference that might change the nature of the truth in different scenario) Or is the theory true? (my example of how quarks are unobserved observables).

Based on these two examples (the science that focus on problem solving and the science that focus on knowledge generating), it seems that science is twofold. On one side, there is the desire for technological advancement, on the other side is the desire to find out the true nature of the universe. The point of view that one merely needs to aim for empirical adequacy doesn't conform with the desire for knowledge. And therefore rejects a whole side to science.

I stand with Colin that for me a science that doesn't provide empirically adequate data, should always be scrutinized. A 'good sense' is not enough, this is science!

Edit wants to hissssssssssss at one more thing. I have liked 'the all emeralds are green' argument but I don't think it is silly to expect their nature might change. Colin emphasized on it "And you expect emeralds to change color in 2050?" with a

Yet, this is also a conundrum in science, especially in Cosmology We can never take the rules of physics to be the same in the past as they are now. We can never be sure that in the early stage of the universe, the law of physics that govern nature now was the same. Why not we expect the emeralds to change their nature? Many people, naively, thinks that the only the man made rule and the world governed by it changes, but it is absolutely possible and even 100% Sure that the rules of nature and the laws of physics are also subject to change. unfortunately cannot

Page2000: Photons are orb stuff.

CoIin: It's always a pleasure to read your intelligent and thoughtful posts, Slasian.

Your first paragraph nicely encapsulates the attitude of many skeptics of scientific realism such as myself. If your theory works, fine. If you have two or more logically incompatible theories that work equally well in the same domain, that's fine too; one is as good as the other. Theories are better thought of as tools or instruments than claims to knowledge of an unobservable reality. Never mind which one of them, if any, is REALLY TRUE; a question best left to unemployed Pink Floyd fans.

Yes, Slasian, everyone agrees, the observable/unobservable distinction is vague, but does that imply it can't be significant? See two of my posts on page 9 for more: the one beginning "Your post is insightful and thought provoking as always ...", and especially the one beginning "@ Bourbaki -- I offer an analogy ..." where I draw a parallel with the continuum from a newly conceived embryo to a fully grown human.

For most of us, there is no instant at which the embryo suddenly becomes a human being, but few of us would deny a qualitative and significant distinction between the two extremes. Similarly, we might consider the everyday objects of perception -- tables and chairs -- at one end of a spectrum, and quarks at the other. There is no sharp line of demarcation where the observable ends and the unobservable begins, but the distinction is valid nonetheless.

It's also true that scientists and philosophers tend to draw the observable/unobservable distinction rather differently; scientists more permissive, philosophers more restrictive.

Van Fraassen, if I recall correctly, would disagree with you about dinosaurs being "unobservable". He would categorize your dinosaurs as "observable in principle". Stegosaurs and pterodactyls may never have been observed in practice (except by Raquel Welch ), but in principle are perfectly amenable to direct observation even granting the limitations of human perceptual apparatus. Likewise for distant planets and their ilk; if we got closer, we could see them. Quarks and their unfeasibly diminutive cousins, on the other hand, just don't fit the bill.

This also can, and has been, challenged though. Human perceptual capacities remain at the mercy of evolutionary mutation and adaptation. I recall one fanciful fellow suggesting that if a mutant human were born with electron microscope eyes, then atoms would be perfectly observable.



I enjoyed your comments about Pierre Duhem and his advocacy of "good sense". This hits a certain nail right on the head, I think. People keep telling us that there exists this thing called The Scientific Method; a logic or rationality of science, but whenever we examine the concept in any depth, we seem to end up in knots, and are left with the advice "Um, just use your common sense, dammit".

Popper, for example, first exhorts us to abandon all theories that disagree with observation. Then he realizes that if scientists dropped all their theories at the first whiff of theory-observation incongruity, they'd have no theories left! He recognizes an element of loyalty or dogmatic defence is required. But at what point does it become unreasonable or irrational to cling to a theory in the presence of prima facie falsifying evidence? -- and that means EVERY significant scientific theory. Well, we can almost hear Herr Popper mutter impatiently "Use your common sense, dammit! "



As for emeralds changing color in 2050, I know what side I'd bet on (remaining green vs changing color) and I think I know on which side you'd bet the Slasian family fortune too, oh slimy one.

But it does raise an interesting logical question: Is the scientist who asserts immutable laws of nature in any better shape than the gambler who bets on "Red" in roulette for no other reason than that black has come up ten times in a row? Or, for that matter, because RED has come up ten times in a row? -- depending on whether our gambler subscribes to a policy of induction (more-of-the-same) in the latter case, or counter-induction (time-for-a-change) in the former.

Is the scientist committing the "gambler's fallacy"?

en.wikipedia.org/wiki/Gambler's_fallacy

I'd bet on emeralds remaining green, and planets continuing in their present orbits, and copper continuing to conduct electricity -- and I'd bet heavily too. But scientists do not claim HUNCHES about putative laws of nature; they claim KNOWLEDGE. And knowledge is generally taken to be JUSTIFIED true belief.

We must look then to justification.

Can the gambler justify his belief that red will come up again? I don't think so, but then again, I doubt the gambler will be claiming KNOWLEDGE. And can the scientist offer any non-circular justification for her belief that emeralds will remain green? If not, whence cometh this "knowledge"? Or can she only argue that she expects emeralds to remain green in the future because they have always remained green in the past?

See the loop?

This IS the problem of induction in science.

And this IS Sparta!



Finally, the video below contains a synopsis of Bas van Fraassen's antirealist Constructive Empiricism project and its implications for unobservable reality. The material explicated therein may prove overly demanding for beginners, who are advised to advance directly to the next post.