--- In [EMAIL PROTECTED], "Marvin Long, Jr." <[EMAIL PROTECTED]> wrote:
>
> Super-super-nitpicky question: if science is only about what we observe,
> how can we draw inferences about what happens to electrons between
> observations? In other words, if what we know about electrons prevents us
> from making inferences about their spin, position, and polarization
> between observations, isn't there a leap of logic required to conclude
>that they *don't* have any properties between observations?
>
In quantum mechanics, the particles are in a superposition of states between
observations. (Including the times, of course, where the weight for one
state is 1 and the weights for the other states are 0. An example of this
is the spin in the direction that one has just measured direction. It stays
the same.)
The time evolution of those states describes the particle with time. When
the particle is observed, the superposition collapses and only one state
exists. But, between observations, the particle is in a superposition of
states.
Various hidden variable theories have been put forward, with the premise
that the particle really has definite properties at all times. These became
problematic when Bell showed that all such theories are nonlocal: they
either violate SR or the have backwards in time signals.
>Another and sort of stupid way of phrasing this question might be:
>if particles don't have properties between observations, what does
>that imply for all our theories about the state of the universe
>between the Big Bang and the evolution of life?
The time evolution of the superpositions handles that just fine.
>
> Or, if "observations" really means "interactions (whether humans see them
> or not)," do the particles' lack of defined properties between
> interactions really matter, as long as we can understand the rules by
> which they interact when they do so (i.e. as long as QM works)?
>
> I guess the realist in me says, "If we can understand electrons well
> enough to make predictions about how they will behave and would have
> behaved billions of years ago, before humans even evolved, then we must be
> pretty confident that they don't require human onservation to exist!"
>
> > >1. Is realism, so defined, a metaphysical theory or an empirical/
> > >physical generalization?
> >
> > It's metaphysical, as far as I see. Theories of science do not address
the
> > ontological status of what we observe.
>
>It often seems to me, though, that you feel that QM does have implications
>for the ontological status of objects. Or do I misunderstand you?
No, I do feel that way. But, when I do, I have my philosopher hat on, not
my scientist hat.
>
> > If you expand your definition of
> > realism to merely make it "there are things that really exist apart from
our
> > observations" then Plato was a realist. But, Plato is considered the
poster
> > child of idealism.
>
>Yes, but Plato's brand of idealism doesn't imply (as far as I can recall)
>that somebody has to observe things in order for them to exist--he's not
>Bishop Berkley.
Well, that's an interesting question, because Plato doesn't develop the
source of the fire for the shadows. But, for Berkley, the existence of
ideas is not dependant on the existence of man. The same is true for Hegal,
who believed in Mind.
> His point is that the world we observe is a shadowy
> reflection of something more real, more ideal (and, ironically, his brand
> of idealism used to be called "realism," meaning that one believes that
> ideals and concepts have a genuine and independent reality, as opposed to
> the doctrine of nominalism, which supposes that ideas and concepts are
> simply artifacts of thought and perception, i.e. names for things). But
>that might be a little OT for this discussion....
Well, Plato thought the world was just a reflection of reality, and that
philosophers, through deep thought, could understand the true reality of
idea. Aristotle, on the other hand, thought that one could obtain an
understanding of reality by observation of the world; and that the world
itself was a primary reality. The spheres of his were a description of that
reality.
>
> > >If realism is truly a metaphysical theory, however, then one should be
> > > able to understood it as eschewing from making statements or
> > > predictiona about the structure of what we colloquially call the
> > > physical world (hence *meta* physics).
> >
> > Actually the term metaphysics comes from Aristotle's book metaphysica,
which
> > was so named because it was the book after Physica.
>
> Yeah, but the usage has evolved since then.
>
But for realists, one can make metaphysical conclusions from observations.
>
> But what? What definition of nomenon corresponds to that which we see in
> QM? If I'm reading Kant correctly, science should never be able to
> perceive, detect, or observe anything that "looks a lot like nomenon."
>
That's absolutely true. But, if you look at all the major interpretations
of QM, including the realistic ones, they are all based on something we
cannot perceive, detect or observe. That's my main point. Even the
realistic interpretations are forced to posit something undetected and
probably undetectable that is the realistic basis for QM.
> Yes, and here's one of the tricky things about metaphysics...in order to
> matter it has to have consequences (moral, intellectual...something) for
> something in "the real world," however one chooses to define it, which
> leads me to some thoughts on realism.
>
> First of all, "realism" is a word so loaded with historical baggage that I
> think it's important to know which flavor of it one wishes to refute.
> My "gut-level" instinct about realism is that it has to have something in
> common with empiricism and skepticism; it seems to me that it would be
> consistent with (some kinds of) realism to say that knowledge is
>eminently possible but metaphysical certainty isn't.
Well, I'm arguing with Objectivists now that one cannot obtain metaphysical
certainty from observations. I'm also arguing with a couple of analytic
philosophers who tend towards realism, who agree that certainty isn't
possible, but eminently reasonable and highly probable conclusions can be
obtained. From my unscientific survey, I think most realists are in this
camp.
>On the other hand, I
>know that there are realists out there who go to great pains to try to
>demonstrate that science provides us with some kind of metaphysical
>certainty, and I'm skeptical about those theories too.
>
>I'm not convinced that realism requires such assumptions.
Well, perhaps not. But then they require a hidden falsification of
scientific theories (which is a problem for a realistic theory) or realistic
backwards in time signals. I guess this can still be realism, but it's a
funny kind of realism that requires the existence of a problematic real
unobservable to explain what we see. With that kind of latitude, I can
probably resurrect Aristotle's spheres.
>
> Secondly, the definition of realism that you offered us at first, Dan--
>
> "Realism is the philosophy that there is a real world, apart from our
> existance and that we have direct access to that world via our senses.
> Books, tables, chairs, electrons, stars, the universe all exist apart from
> our observations."
>
> --is problematic because of your inclusion of the word "electrons." By
> equating electrons with chairs, you basically add to realism a version of
> the physical theory of atomism, the notion that all matter is made up of
> really tiny unreduceable particles which, aside from being really small
> and more basic in structure, are really no different in quality from
> chairs and tables. Again, realism ceases to be a metaphysical theory and
> instead becomes a theory of classical physics, after a fashion, so of
> course QM undermines it.
>
People have tried, fairly early on actually, to come up with a macroscopic
realism/microscopic non-realism. They have tended to fall apart answering
the question: at what size to things cease to be real. Are molecules real?
Are things we need a microscope to see real?
>So the question that I'm putting to both of us is, is there a
>metaphysical form of realism that doesn't commit itself to any particular
>theory of physics?
The problem is not just a commitment to a particular theory of physics. The
problem is that a theory of physics that is well validated has elements
that, on the surface at least, contradict assumptions made by realistic
philosophies.
>I think one of the issues for realism (and
> empiricism, and especially skepticism) is that it's often a rejection or
> negation of somebody's more idealistic metaphysics. There's a sense which
> which realism and its sister philosohpies says "metaphysics is a waste of
> my time, the only reason to engage in it is to discredit the outlandish
> claims of other metaphysicians."
>
> Personally, I'm not entirely sure that there can be a realism that doesn't
> depend on empirical observation in some way. But I think that it is
> possible to say without invoking any assumptions of physics that, 1) the
> world exists independently of me but not I of it; 2) the world is
> consistent in its laws; 3) I experience the world directly through the
> senses; 4) because of 2 and 3, knowledge is possible (maybe not
> omniscience, or metaphysical certainty, but knowledge). To me this feels
> like making an inference from experience, so it might not qualify as
> metaphysics. The metaphysics, such as it is, might come from evaluating
> and rejecting such concepts of the nomenon and Platonic Forms as
> unnecessary to explain experience and unsupported by evidence.
>
>
> > Well, I tend to agree with Kant, but he wasn't a realist. Realists
believe
> > that we can gain understanding of reality through observations. If you
> > read realists like Aristotle, Aquinas, early Wittgenstein, you will tend
to
> > get that feeling. Barkely and Hume were empiricists, and doubted the
> > possibility of certain knowledge at all. They argued that even systems
of
> > mathematical understandings were based on empirical observations.
> > So, if you think of it, all I am saying is that Kant was write in that
the
> > empirical is not the source of metaphysical cognition.
>
> I'm not saying that Kant's a realist, just that his definition of
> metaphysics implies that no theory of physics has the power to lend
> support to his own metaphysics.
>
> > > 2. How can any scientific discovery, if science is so defined, have
any
> > > consequences, for or against, any metaphysical theory, whether that
theory
> > > is realism or Kant's?
> > >
> >
> > Well, that is a reasonable question. The best way to say this is that
the
> > strongest realistic philosophies tend to have general observable
> > consequences. If you asked most realistic philosophers from the last
2000
> > years if part of their metaphysics was that trees, rocks, oceans, etc.
> > existed apart from humans, they would respond, (probably unanimously)
with a
> > loud yes.
>
> And so far it's pretty hard to refute that theory, QM or no. :-)
Well, there's the quote of Wheeler
"You may say that I am just a small spec in the universe, and that is true.
But, the universe itself would not exist for a primitive act of
registration."
Let me phrase it this way. Lets go from something medium sized to smallest:
Tree
Cell within tree
Nucleus within cell
DNA within nucleus
A water molecule
Hydrogen, oxygen, and carbon atoms
Protons and neutrons
Electrons, quarks, and glueons
At what point do things cease to have independent existence? What is the
minimum size that something can have and still exist independent of human
observations.
> Although: QM does suggest that by existing in the universe, humans are a
> part of *everything* by means of the entanglement of particles. It just
> doesn't imply that human observation is a prerequisite for everything else
> to exist. Dead humans would be just as connected to the universe by
> particle entanglement as live ones.
>
Actually, I think that QM suggests something stronger. The universe is our
organization of what we observe. It is highly probable that stuff exists
apart from us; its just that the universe is our model of phenomenon and
thus dependant on us for existence.
>
> But how does does that consequence of QM bear any resemblance to the
> noumenon? I could be remembering Kant totally incorrectly, but IIRC
> Kant's theory is that all observable phenomena have an aspect, defined as
> "noumenal," which *does* exist but can only be observed from a
> transcendant point of view, i.e. by some kind of super-Pure Reason, a
> viewpoint that has no physical or sensual intuitions or perceptions (i.e.
> it's very much like God).
>
In the sense that noumenon is that stuff that exists apart from our
perceptions and that phenomenon results from the interaction between our
minds and that stuff.
> IOW, everything that humans observe is perfectly "real" for the purposes
> of scientific investigation, but everything also has a transcendant aspect
> that is also *more* real and which can only be apprehended directly by a
> being with a similarly transcendant point of view, which humans aren't
> privileged to have.
>
True. We don't see nomenon, that's absolutely true. What we see is the
difficulty in defining the objects of phenomenon in a manner consistent with
them being things in themselves. IMHO, this suggests a nomenon that is
comprised of things-in-themselves behind the phenomenon.
Dan'm Traeki Ring of Crystallized Knowledge.
Known for calculating, but not known for shutting up
