Reductionism: Physics-Chemistry-Biology

fls said:
I think you misunderstood. I think Schneibster was referring to parity, not chirality, in that list following the semi-colon.

He could be asked, I suppose.

Linda
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You are correct. Not that I expect our troll cares. But that's not your problem. ;)
 
DeviousB said:
(a) Because you say experimentation is not a part of mathematics.
<snip>
Because you exclude experimentation from mathematics.
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Worth mentioning that the determination of whether a particular point arbitrarily close to the border of the Mandelbrot set is actually a member of the set or not cannot be done by formula; you can only run the Mandelbrot equation over and over again and see if the point eventually falls within the border or not. In other words, run an experiment. On your computer. The result of which you cannot predict in advance.

That should close off this avenue quite effectively.
 
Schneibster said:
You get one shot. Use it wisely.
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Hmm...

OK.

You may be a Physics genius, but you appear to know b***** all about organic chemistry.

Chirality cannot be described in physics. Any description you care to make of a chiral molecule, based on simply the tools avaliable in physics, will be indistinglishable from it's mirror image.

So there is no way, if you stick to atomic or sub partical properties (ie physics), of describing how, for example, L-Glucose and D-Glucose differ.

PS I am a Synthetic Organic Chemist FYI

PPS You really need to get a handle on the concept of Emergence, maybe if you actually understood the phenomena of emergence, you would't come across as being so ignorant, outside the realm of physics, and you would be able to see that in this case, you are wrong, and slimething is right.
 
Schneibster said:
You are correct. Not that I expect our troll cares. But that's not your problem. ;)
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Ah, our confabulator is back. Hiding in the corner until you thought it was safe to come out, little one? So, you can't read and now you can't write either. Is that it? Some physicist. :eye-poppi ROTFLMFAO

Just for jollies, why don't you parse priceless post #104 so that you can weasel your way out of it? I mean, you were writing about molecules, yes? Or were you somehow confused with the mirror images of electrons? (Do you even know why electrons can't have mirror images, schneib?)

Anyone can be a physics genius when they have more qualified apologists sitting by ready to correct their mistakes. Hell, if I had your crowd around, I could say that atomic masses are based on carbon-12 having a mass of exactly 627. Then someone who knows better would tell me I was wrong. Soon, my posse would show and tell the person I really meant 12. Then I could show up and say that was, of course, undoubtedly what I meant. Hey, Dorothy, pay no attention to the man behind the curtain!

What a laugh. You're a fraud, shneib. Science has many routes to the truth but lying, slander and falsification are verboten. They are prohibited states (if you even know what that means).

BTW, quote something from Harrison's book just so we really know you have a copy, OK? Post one of those wonderful templates so I can plug it into Excel and match it up with a real chemistry value. And, no waiting until tomorrow so that you can't order the book fedexed, OK?

You have a fan club, schneib. They're all much nicer than you are. These are real human beings, so different from you. Take a page from their book. Don't write about stuff you know nothing about and always expect to get out what you put in. Never too late, y'know.

However, you're a fraud. A phony. Too bad/so sad. Sucks to be you. and all that jazz. :)
 
Oldpossum said:
PS I am a Synthetic Organic Chemist FYI
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I'm an organic analytical/pharmacokinetic chemist. Good to meet you. :)

You arrived not a minute too soon. We've got a mad physicist on the loose who thinks he own the truth and the JREF and doesn't have to conform to any rules of civility or fair play.
 
Slimething said:
Anyone can be a physics genius when they have more qualified apologists sitting by ready to correct their mistakes. Hell, if I had your crowd around, I could say that atomic masses are based on carbon-12 having a mass of exactly 627. Then someone who knows better would tell me I was wrong. Soon, my posse would show and tell the person I really meant 12. Then I could show up and say that was, of course, undoubtedly what I meant. Hey, Dorothy, pay no attention to the man behind the curtain!
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I just wanted to clarify that I am not an apologist for Schneibster. I don't know Schneibster, nor do I recall interacting with him previously,* although I have read many posts by him. I'm no slouch in physics, but I doubt I am more qualified than him (this is just a guess).

He wrote a sentence that was ambiguous. I resolved the ambiguity by realizing that his entire post only makes sense if he is referring to parity. I thought that pointing this out would mitigate a source of conflict (yes, I am that stupid :)). This was before I actually went back and read the rest of a thread that I had been following only half-assedly. Mea culpa.

Linda

*Imagine my embarrassment if he now reminds me of our night of unbridled passion at the last TAM. In my defense, I was probably drunk.
 
Slimething said:
Ziggurat, that hypothesis would hold water were it not for the sentence where he first made it clear that he was writing about molecular chirality, that is the chemistry kind. Chirality, used in physics, is reserved for subatomic particles.
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No, actually, it isn't. The word itself isn't used much outside subatomic particles, but the right-hand rule for magnetic fields in E&M is precisely chirality, and it's about the first thing you learn about magnetism in physics.
 
LOL, no, I'd recognize your avatar if we'd talked much; I think I've seen your posts around a couple times. I've never been to TAM, so you don't have to worry about THAT, anyway.
 
Schneibster said:
LOL, no, I'd recognize your avatar if we'd talked much; I think I've seen your posts around a couple times. I've never been to TAM, so you don't have to worry about THAT, anyway.
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I wasn't that worried, since I've never been to TAM either.

Linda
 
Ziggurat said:
No, actually, it isn't. The word itself isn't used much outside subatomic particles, but the right-hand rule for magnetic fields in E&M is precisely chirality, and it's about the first thing you learn about magnetism in physics.
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You're right, ziggurat. Chirality is not used as a definitive term in the left- and right-handed rules for electricity and magnetism. It is there in spirit, if nothing else. However, it's amply clear from your friend's post that he was refering plainly and distinctly to molecular (chemical) chirality.

I know what you're getting at. You think I'm being too harsh on schneib and that I'm over-reacting to his "in your face" style of posting. Perhaps calling him a fraud is jumping to an unwarranted conclusion. I am a chemist, not a physicist, so I have no qualifications to judge him as the latter. However, I do know a liar when I catch them lying.

I'll take your word concerning his credentials on physics. However, no one can review his postings in this thread and make any claim that the man exhibits the type of integrity that scientists should have if we, as a class, have any chance in prevailing against our detractors. If you still believe in the man as an authority, you do so at your own risk.
 
Oldpossum said:
Chirality cannot be described in physics. Any description you care to make of a chiral molecule, based on simply the tools avaliable in physics, will be indistinglishable from it's mirror image.

So there is no way, if you stick to atomic or sub partical properties (ie physics), of describing how, for example, L-Glucose and D-Glucose differ.
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not all physicists "stick to atomic or sub partical props", and i imagine few physicists would agree to the claim that they could not distinguish L-Glucose and D-Glucose. i regret not knowing more chemistry, so before i start making silly naive-physicist's guesses about optical properties, perhaps you could tell us how you distinguish them empirically?

thx
 
DeviousB said:
Only if physics is not maths. But physics is maths, hence what you call doing physics is merely determining the initial conditions of the maths.
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i would like to understand why you feel physics is math. math has no empirical aims/content: to prove 2+2=4 says nothing about the world and does not attempt to. maths provides a language and some tools, but physicists speak badly and misuse the tools and remain proud of the result... hardly evendence that one can be reduced to the other.

one might argue that maths is "bigger than" physics, and that only by experimentation do we find the bits of maths that appear relevant: physics cannot be reduced to maths in that case as the empirical component is not within maths (nor do mathematicans care to have it).

or one can argue (a la nancy cartwright, a philosopher who now is now where popper was) that physics does NOT follow mathematics, but makes arbitrary choices that cannot be justified on mathematical grounds, but only on physic's grounds (it gives the "right" answer).

or one can argue that, in fact, the world is not described (in mathematical precision) by mathematics; that while we have a remarkable useful descriptions of some things at some times, but mathematics does not do the job precisely enough.

in any of those three, physics cannot be "reduced to" maths. in what way do you think that it can be?

thx
 
lenny said:
not all physicists "stick to atomic or sub partical props", and i imagine few physicists would agree to the claim that they could not distinguish L-Glucose and D-Glucose. i regret not knowing more chemistry, so before i start making silly naive-physicist's guesses about optical properties, perhaps you could tell us how you distinguish them empirically?

thx
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1) Measure the optical rotation of a pure solution, using a polarimeter, one enantionmer will have a + value, and the other a - value, a racemic mixture will show no optical rotation.

2) Use as a food base for a particular strain of Lactobacteria. On one substrate (The L) the bacteria will not thrive, but on the other substrate (the D), the bacteria will thrive. (The bacteria only have enzymes for digesting the D-glucose, so can't use the L-glucose as a food source.
Remember, Enzymes have chirality too, so can vary in their reactivity, to the handeness of other chiral molecules.)

3) Taste. they have slightly different tastes. (that's because the receptors on our taste buds are chiral too, so there is a difference in how each enantiomer matches up with a taste receptor.)

4) Complex with a chiral Spin-coupling agent, then run throught an NMR.
The chiral spin coupling agent will cause the frequency of one enatiomers peaks to shift up slightly, and the other enantiomers to shift down slightly; So you will see the NMR of a racemic mixture, display a splitting of the peaks.

Any other physical test, not based on one of the above, will fail to tell the enantiomers apart, because in every other physical property, they are identical.

So basicaly, in order to differentiate the enantiomers of a chiral molecule, you need to resort to using another chiral molecule, to force some sort of breakdown in symetery matching. (Except The polarimiter uses a crystal, or a diffraction grid, to force light into a single plane of polarization; But this could be considered, to be just another way of forceing, a breakdown in symetery matching.)
 
lenny said:
i would like to understand why you feel physics is math. math has no empirical aims/content: to prove 2+2=4 says nothing about the world and does not attempt to. maths provides a language and some tools, but physicists speak badly and misuse the tools and remain proud of the result... hardly evendence that one can be reduced to the other.
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If we are defining reductionism to mean 'ontological reductionism', then physics is just maths. No entity in physics, however simple, is not a compound mathematical entity in just the same way that no biological entity, however simple, is not also a compound physical entity.

What you are arguing is methodological reductionism, that the methods and processes of physics (the science) must also reduce to the Ms and Ps of maths for reductionism to be meaningful.

Actually, I would agree with you and have argued for MR on this thread, however the claim was made that biology reduces to physics (because nothing biological is not made of things physical, i.e. OR), but physics does not reduce to maths (because to use the maths you have to do the physics - i.e. MR). To me this is a 'cake and eat it' thing.

in any of those three, physics cannot be "reduced to" maths. in what way do you think that it can be?
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In the way that biology reduces to physics.

Under MR, neither (completely) reduces. Under OR, both (pointlessly) do.
 
Oldpossum said:
So basicaly, in order to differentiate the enantiomers of a chiral molecule, you need to resort to using another chiral molecule, to force some sort of breakdown in symetery matching.
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And nothing would stop a physicist from introducing another chiral molecule also. A physicist attempting to analyze a system of chiral molecules from the first principles of quantum mechanics certainly would realize the electron clouds interact differently depending on the symetries of the clouds involved. There is no theory in biology that predicts the chirality of our molecules any more than there is one in physics. It's determined empirically and then worked with from there. Physics and biology are on equal grounds in this regard: the unexplained chiralities noticed by the physicists are presently assumed to be accidents of symetry breaking from the origin of the cosmos, similarly the chiralities of biological systems are though to be an arbitrary "choice" based on some similar accident at the beginning of life.

So, basically there is no reason that the problem of chirality can't be, in principle, addressed by physics. As with other objections to whatever not being able to reduce to physics, the obstacle is computational power. There simply isn't computational power available to solve these problems from the first principles of physics (BTW I wouldn't be surprised if your method 1 (optical rotation) can be addressed from first principles with available computers).
 
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Oldpossum said:
1) Measure the optical rotation of a pure solution, using a polarimeter, one enantionmer will have a + value, and the other a - value, a racemic mixture will show no optical rotation.
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Optical rotation is a result of off-diagonal terms in the susceptibility tensor. Physics can and does deal with off-diagonal elements.

(Except The polarimiter uses a crystal, or a diffraction grid, to force light into a single plane of polarization; But this could be considered, to be just another way of forceing, a breakdown in symetery matching.)
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Sure, but that kind of symmetry breaking happens all the time in physics. And it's not even confined to molecules, either. The same basic principle (off-diagonal terms in the susceptibility tensor) is at play in optical Kerr rotation, for example, and that's used quite frequently by condensed matter physicists who study magnetic materials (because ferromagnetism also breaks chiral symmetry).
 
Ziggurat said:
Optical rotation is a result of off-diagonal terms in the susceptibility tensor. Physics can and does deal with off-diagonal elements.
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Yes. More theoretical physics promulgated at describing empirical observation. Nice.

That wasn't the argument being misrepresented by schneibster, though. He wrote that one could predict optical rotation and many other physical traits of molecules strictly from the physics of bonding and knowledge of atomic orbitals. Maybe he'll show up soon with another made-up book about this very exact thing from his Fantasy Collection.
 
Most biochemists don't know enough physics to discuss optical rotation sensibly.

It's really quite simple; you see, the electrons in the outer shells absorb photons that have the same spin chirality they do, and don't absorb ones that don't; and you can only measure spin on one axis at a time. So each one is either up or down, compared to the electron, and if it's down, it gets absorbed. When the electron re-emits it, in order to conserve both spin and momentum, it has to emit it with a rotated spin axis. But that's only if it is in the same axis as the electron- otherwise, it doesn't absorb it.

Now consider that polarization is sorting by spin along one axis.

If that doesn't give you enough clues to figure it out, you'd better give up.

I absolutely know that all biochemists can't be that stupid.
 
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