Re: No Such Thing As "Macro" Evolution

r norman wrote:

> On Sun, 27 Nov 2005 09:10:24 -0700, dkomo <dkomo871@xxxxxxxxxxx>
> wrote:
>
>
>>r norman wrote:
>>
>>
>>>On Fri, 25 Nov 2005 13:28:07 -0700, dkomo <dkomo871@xxxxxxxxxxx>
>>>wrote:
>>>
>>>
>>>
>>>>r norman wrote:
>>>
>>>
>>><snip>
>>>
>>>>>You also believe that we know what a
>>>>>"force" is, as well as what "mass" is.
>>>>
>>>>Force is a simple generalization of our body-centered notions of a push
>>>>or pull. Mass is a generalization of our simple notions of heavy or
>>>>light. These are what Kant would call a priori categories of the mind.
>>>>Our minds have these categories because our minds evolved to help us
>>>>survive in the world. So these categories are rough approximations of
>>>>what actually exists.
>>>>
>>>
>>>
>>>You mistake appearance for reality. There are events which we
>>>perceive as being pushes or pulls and think that this must translate
>>>directly into "force". It is true that elementary physics is taught
>>>be starting with "elementary" notions like force and mass and position
>>>and then generating "derived" concepts like momentum and energy which
>>>are quite abstract and don't really correspond to anything we
>>>experience. But it really turns out that momentum and energy and
>>>really the fundamental factors (in Newtonian mechanics), being
>>>conserved quantities while force is something quite abstract.
>>
>>I don't think most civil and mechanical engineers will agree with you.
>>For them forces are as real as anything can be. Forces need to be taken
>>very seriously, otherwise the structures will collapse or the machines
>>will fly apart. Look into the Schaum's Outline on mechanical
>>engineering in the section on "statics" and you'll see dozens of
>>examples of structures that bristle with force vectors drawn every which
>>way.
>>
>> In
>>
>>>fact, a "force" is really the negative derivative of (free) energy
>>>with respect to a thermodynamic extensive variable. So instead of
>>>saying that force times distance = work = negative energy (it takes
>>>energy to do work), it is more proper to say that force is the
>>>negative derivative of energy with respect to distance. And the
>>>"force of diffusion" is the negative derivative of energy with respect
>>>to moles moved. It is really changes in energy (and associated
>>>entropy) that are the "causes of action" in the real world, not forces
>>>pushing on things.
>>>
>>
>>I thought we started talking about Newton and his time. You're
>>describing ideas that were developed over the next few hundred years
>>after Newton. I don't recall that Newton ever mentioned "energy" or
>>even "momentum". For him, it was forces all the way.
>>
>>
>>>Mass is somewhat different but similarly hard to pin down. Mass is
>>>something that, in a gravitation field (whatever that is) produces
>>>"weight, or better, results in gravitational potential whose variation
>>>acts as a force. Mass is something that produces inertia (in the
>>>sense that F = ma) or, better, that relates motion with momentum.
>>>What earthly (or unearthly) reason is there to suggest that these two
>>>notions of mass have any relation to each other?
>>>
>>
>>Nonetheless, mass has simple correlates to our everyday world. Lifting
>>something massive is hard work (hah -- it takes energy!) Lifting
>>something that is not massive is easy. I think even Aristotle
>>recognized mass as being an important quality of material objects,
>>although he may have given it a different name.
>>
>>
>>
>>>Our minds have a priori notions of energy -- we use it up pushing
>>>against a brick wall and come away exhausted even though we do zero
>>>physical work.
>>
>>Yep. I agree. The basic ideas of energy are quite down to earth.
>>
>> What physical reality corresponds with our mind's a
>>
>>>priori notions of joy or beauty or goodness? "Our minds have these
>>>categories because our minds evolved to help us survive in the world.
>>>So these categories are rough approximations of what actually exists."
>>>Really?
>>>
>>
>>Thanks for making my point. Joy and beauty and goodness are innate
>>human experiences. They are indeed "a priori".
>>
>
>
> To be quite frank, I really don't know just what the point is any
> longer.
>
> You talk of the "reality" of forces and I refer to modern physics
> which, after the introductory level, puts the notion of force into a
> secondary position albeit useful in doing calculations. You respond
> either by citing engineering applications which are all about doing
> calculations and by introductory level works.
>

I don't agree that forces have been put into a secondary position. The
mathematical reformulation using the negative derivative of energy is a
generalization and reformulation of the older scheme regarding forces,
but not a replacement.

Other examples of this kind of reformulation are Hamiltonian and
Lagrangian dynamics, Hamilton's principle, and the principle of least
action. These extend, but do not replace Newton's laws or the concept
of forces.

Marion says:

"First and foremost, it must be reiterated that Lagrangian dynamics does
not constitute a new theory in any sense of the word. The results of a
Langrangian analysis or a Newtonian analysis must be the same for any
given mechanical system: it is only the method used to obtain these
results that is different."

"Whereas the Newtonian approach places the emphasis on an outside
ageancy acting on a body (the force), the Lagrangian method deals only
with quantities which are associated *with* the body (the kinetic and
potential energies). In fact, nowhere in the Lagrangian formulation
does the concept of force enter."

--Marion, _Classical Dynamics of Particles and Systems_, p. 212

Does general relativity *replace* Newton's Laws? If it did it would be
news to NASA, who continues to calculate the orbits of space vehicles
using the same methods of celestial mechanics developed by Laplace
hundreds of years ago. If GR were easier to use, NASA would use it, but
the fact is that for calculating orbits the mathematics is considerably
more difficult.

And the argument that calulation is somehow trivial and "introductory"
compared to heavyweight theory is silly. Calculation in physics
involves theory. I'm just pointing out that Newton's laws involving
forces are still very much alive for the people using them.

> You talk of a Newtonian universe and I refer to modern physics and
> its current knowledge of that type of universe (even without invoking
> quantum mechanics or relativity). You respond by saying we were
> talking about Newton, himself, and his concept of the universe.
>

I was trying to preserve the historical definition of the "Newtonian
World Machine" when you switched the subject over to modern classical
physics (as of the end of the 19th century).

"In Newtonian mechanics all physical phenomena are reduced to the motion
of material particles, caused by their mutual attraction, that is, by
the force of gravity. The effect of this force on a particle or any
other material object is described mathematically by Newton's equations
of motion, which form the basis of classical mechanics. These were
considered fixed laws according to which material objects moved, and
were thought to account for all changes observed in the physical world.
In the Newtonian view, God created in the beginning the material
particles, the forces between them, and the fundamental laws of motion.
In this way the whole universe was set in motion, and it has continued
to run ever since, like a machine, governed by immutable laws. The
mechanistic view of nature is thus closely related to a rigorous
determinism, with the giant cosmic machine completely causal and
determinate."

--Capra, _The Turning Point_, p. 66


You really added nothing to change this picture with your remarks about
energy and thermodynamics. The only thing that was added in the 19th
century was the random motion of "particles" (atoms), but the analysis
was such as to preserve the "causal and determinate" view of nature.
Randomness was not fundamental, but resulted from our inability to
individually keep track of all the particles, forcing us to use statistics.

And my original statement that today's biology pretty much adheres to a
Newtonian world view still stands.

> You talk of our minds having a priori notions of things that have
> physical reality and I point out that our a priori notions often
> diverge enormously from physical reality. You respond by saying that
> is exactly your point.
>

Probably a misunderstanding. I was trying to say that our physical
theories *start* from fundamental a priori perceptions of nature
bequeathed to us by evolution (e.g. body-centered notions of force,
weight and work/energy), then grow increasingly abstract as we
generalize these basic notions. This is a point of view started by Kant
and is being continued by cognitive science which, is actually able to
map many of these perceptions to areas of the brain where they are used.

> ?????

HTH.


--dkomo@xxxxxxxx

.

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