Reductionism: Physics-Chemistry-Biology

[geni]

You aren't under the mistaken impression that the Schrödinger equation cannot handle kinetics, are you?

Stikes me as being a rather overcomplex way of trying to model the differences between H₂O and D₂O

And yes, the Schrödinger equation can be solved numerically for arbitrary numbers of particles (if you've got the computational power).

Those are only approximations. To be able to reduce chemistry to physics you would need to be able to show that it is posible for an analytic solution to exist for all systems that appear in chemsitry.

Throw in structures that do anoying things such as haveing both quantum and mocro properties and at the present time phyics is still working on chemistry.

 

[Schneibster]

First of all you should note that winning isn't always about being right. I suggest you consider which is more important to you before you continue this line of conversation.

I will, however, give you some food for thought.

Hey guys,

Well I'm having this argument with a close friend of mine who's about to begin her 2nd year of undergraduate science. The argument is essentially about the most basic form of reductionism: I explained that physics 'comes' from mathematics, chemistry comes from physics and biology comes from chemistry.

I'd argue that physics doesn't come from math, rather more the other way 'round. However, physics does come from observation of the behavior of the world around us; and math describes that behavior.

She's someone who loves chemistry and seemed angry at the suggestion that it is reducible down to physics... I gave some examples of the way chemistry is working off the foundation of physics but they didn't seem to satisfy. I'm wonder if anyone could offer up a simple way to show her exactly what I mean - Or if there really is strong argument out there about whether chemistry is reducible to physics (I'm doubting it).

Thanks.

The fact of the matter is that chemistry is about the combination of atoms into molecules, and the behavior of atoms whether in or out of molecules is described by physics. So you are indeed correct. I caution you again, however, that you may find that being right isn't as important as winning.

 

[Schneibster]

Those are only approximations. To be able to reduce chemistry to physics you would need to be able to show that it is posible for an analytic solution to exist for all systems that appear in chemsitry.

Basically, then, you think that chemistry isn't about atoms?

Whatever you're smoking, I need some. 'Cause man, you are HIGH.

 

[TheChadd]

First of all you should note that winning isn't always about being right. I suggest you consider which is more important to you before you continue this line of conversation.

I was already there shortly after making this post

 

[geni]

Basically, then, you think that chemistry isn't about atoms?

Whatever you're smoking, I need some. 'Cause man, you are HIGH.

Interesting strawman you've got there although there are bits of chemistry that don't worry about atoms they are not areas I deal with.

 

[pgwenthold]

Those are only approximations. To be able to reduce chemistry to physics you would need to be able to show that it is posible for an analytic solution to exist for all systems that appear in chemsitry..

No, you only need to show that it is possible to obtain a solution that is to the level of "chemical accuracy," i.e. the level of accuracy that can be obtained in the empirical science of chemistry.

You are requiring physics to provide exact solutions in a field that is wrought with uncertainty? Why should physics have to provide an exact (analytical) value for anything when chemistry doesn't have to?

If I carry out a measurement that has an uncertainty of 10%, but if I know I can calculate the same value to within 5%, then the calculation is better than the experiment.

 

[Ziggurat]

Stikes me as being a rather overcomplex way of trying to model the differences between H₂O and D₂O

I never claimed that an explicit wave function for a system was the best way of modeling it from a practical standpoint. Of course it often isn't, and I thought I made that rather clear. How one SHOULD solve a problem is usually only a subset of how one COULD solve it.

Those are only approximations.

So what? They are approximations with potentially arbitrary precision.

To be able to reduce chemistry to physics you would need to be able to show that it is posible for an analytic solution to exist for all systems that appear in chemsitry.

Nonsense. Analytic solutions don't exist for Newtonian gravitational interaction of 3 masses, and yet nobody points to that lack as an indication that physics isn't what describes gravity.

 

[Schneibster]

Interesting strawman you've got there although there are bits of chemistry that don't worry about atoms they are not areas I deal with.

Well, if you're dealing with atoms, you're dealing with physics, because that's the science that describes atoms. Chemistry certainly doesn't, at least not in terms of their internal structure; to chemistry, the internal structure of an atom is moot, all you have to know is how atoms combine with one another to form compounds.

I'd like to know precisely what "bits" or "areas" of chemistry you believe don't "worry about" atoms, considering that chemistry is all about how atoms combine with one another to form compounds.

I'd also like to know why, if you're talking about such things, you think that what I said represents a straw man; I responded to what you said, not what you thought you said. Perhaps you should review your posts a bit more carefully before hitting the submit button.

 

[Schneibster]

I was already there shortly after making this post

I hope that's good news.

 

[JamesM]

chemistry is all about how atoms combine with one another to form compounds.

That describes organic and inorganic chemistry reasonably (admittedly, organic chemistry is what most non-chemists think of as chemistry); it's not a good description of physical or analytical chemistry.

To my mind, chemists are more concerned with the behaviour of electrons, albeit normally only the least well-bound electrons. That often involves controlling their behaviour at the level of abstraction that covers a handful to hundreds or thousands of atoms at a time.

 

[Schneibster]

That describes organic and inorganic chemistry reasonably (admittedly, organic chemistry is what most non-chemists think of as chemistry); it's not a good description of physical or analytical chemistry.

"Physical chemistry." I rest my case.

To my mind, chemists are more concerned with the behaviour of electrons, albeit normally only the least well-bound electrons. That often involves controlling their behaviour at the level of abstraction that covers a handful to hundreds or thousands of atoms at a time.

Well, first, "electrons without physics" looks like an oxymoron to me; and second, I don't think the level of abstraction matters much, really. Bear in mind that we are finding more and more out about both chaos math and about scaling laws that affect mass behavior, such as the fluctuation theorem (which has modified our understanding of the 2LOT substantially). If we can't describe the activities of hundreds or even millions of atoms today, the time is not far off either for brute force (have you seen the articles recently about the new resist strategy that Intel or someone came up with?) or elegant (like the FT) descriptions of such things.

And the argument here is, "can the principles of the science of chemistry be reduced to the actions of physics?" And I still contend that the answer is, "yes." That is not, to my mind, any indictment of chemistry either as a science, or as a discipline; that it can be so reduced does not necessarily mean that the goals of physicists and those of chemists can be equated one to another, since chemists are interested more in "what" than "why," whereas the interests of physicists are just about the opposite of that, and I see the answers to neither "what" nor "why" as more important one than the other. I suspect that the contrapositive of that last is the reason that the OP's lady friend was less than pleased with the assertion; perhaps that analysis will help with that.

 

[Mercutio]

To me, the wonderful thing about this silly argument is what happens when the various different levels of abstraction agree.

Lemme 'splain.

I'll start one level of abstraction beyond Biology, actually--Psychology. For most (but, sadly, not all) psychologists, Psychology is a biological science. (For the rest, it must simply be magic.) These psychologists get bent out of shape by biologists claiming that psychology is just biology; these biologists resent the chemists, who are pissed off at physicists, who resent mathemeticians, who are just angry that they can't find dates.

Anyway, at a conference a couple of years ago, a neurobiologist reported on a nerve pathway in honeybees that was moderated by octopamine. His description of the function of this pathway made me think (although it appears he was unaware of the connection) of the Rescorla-Wagner model of classical conditioning. The RW model is a mathematical model that most behaviorists recognize does a fabulous job of predicting classical conditioning phenomena. No behaviorist would ever say "therefore, there is a mechanism that does this"--that would be circular--but it was quite refreshing to hear this guy describing a system, independently discovered, that fits the model exactly. Of course, octopamine would be perfectly describable by a biochemist, and the description would be accepted by any physicist, and so on down the line. It simply worked.

Contrast this with any number of psychological concepts that have been circularly inferred, rather than described from observation. Take the Id, Ego, and Superego: haven't the psychobiologists had enough time to locate these? Don't the biochemists have an understanding? Um...no. They ain't there. Of course, there is no evidence for them in psychology either, other than the behavior they allegedly cause. Purely circular.

Anyway, it doesn't mean the R-W model is right. It just means that this particular evidence does not kick it's feet out from under it. Whereas Freud...or Chomsky's "Language Acquisition Device", or any number of other crap psychology theories...

I love the way sciences mesh.

 

[Jeff Corey]

Me too. We have biopsychologists who confer with the behaviorists on how to measure things like "reinforcement".
Skinner was not a reductionist, in the sense that we have as our task discovering functional relationships at the level of behavior. Sure, in the ideal world, we will discover how reinforcement works at the biological level, but now we try to do what we know best.

 

[lenny]

afield too far

Lemme 'splain.
I'll start one level of abstraction beyond Biology, actually--Psychology. For most (but, sadly, not all) psychologists, Psychology is a biological science. (For the rest, it must simply be magic.) These psychologists get bent out of shape by biologists claiming that psychology is just biology; these biologists resent the chemists, who are pissed off at physicists, who resent mathemeticians, who are just angry that they can't find dates.

it is called physics envy.

(and it stops at physicists, who do not resent mathematicians, although they might sometimes wish the real world was as platonic as many mathematicians believe it is!)

 

[Schneibster]

Heh, I remember reading some popular physics writer saying that when budding physicists get to college and start learning math, the physics professors all go, "Don't pay any attention to the mathematicians, they're off on a power trip, they'll melt your brain, we'll teach you all the math you need to know."

 

[Slimething]

"Physical chemistry." I rest my case.

Rest is somewhere else. You're wrong. Physical chemistry encompasses more than quantum mechanics. It also includes thermodynamics, electrochemistry, and the like. If you want to believe in a Theory of Everything that allows physicists to model everything that chemists do, will do or know, you are entitled but it doesn't exist yet and probably never will. I'm an analytical chemist, I know QM and more than how to make molecules come together.

And the argument here is, "can the principles of the science of chemistry be reduced to the actions of physics?" And I still contend that the answer is, "yes."

And, you'd be wrong. Five minutes in a chemistry lab tripping over your tongue would be enough to convince you of that.

That is not, to my mind, any indictment of chemistry either as a science, or as a discipline; that it can be so reduced does not necessarily mean that the goals of physicists and those of chemists can be equated one to another...

There, I highlighted your strawman for you. If it can be so reduced, do it. I'd love to stay and watch but I gotta go unquestioningly figure out why a molecule fragments in my mass spectrometer in certain pattern.

 

[DeviousB]

Natural selection is an emergent property. That doesn't mean it's not still rooted in physics. The organization of hexagonal convection cells in heated liquids is another example of an emergent property of a complex system. There's no simple way to show that such self-organization is what will result using, for example, the Schroedinger equation, but it's all still just physics. The more complex the system, the harder it is to trace emergent properties back to their physical origin (and often times, the less useful such an exercise is anyways). We label things as being something other than physics when we either can't trace the link (because of the complexity) or don't care to, not because the link doesn't exist.

No-one (in biology) is arguing that biological creatures do not follow the principles of physics and chemistry. And if you want to say NS is 'emergent', fine. But it is strongly emergent; it is not directly explainable by the mechanisms of the underlying system. Ergo, does not reduce.

A mutation with a frequency f in a population of animals P results in a 1% improvement in vision, but also a 2% increase in the metabolic cost of the eye. How might physics tell us about how we might expect f to change over time? Or chemistry?

Chemistry can be reduced to physics because the systems of chemistry are specific cases of the systems of physics, chemistry is a special type of physical interaction. Similarly, biochemistry is a special type of chemistry. Developmental biology is a special type of biochemistry. And so on.

But NS doesn't fit so neatly in this little tree. You don't explain the features of NS with the systems of biochemistry, chemistry, physics, etc. You use NS to explain the complexity in particular examples of these systems that they can't explain.

Beisdes, I thought the so called 'laws of physics' were just a result of natural selection in the first place? Surely then, physics is the emergent process?

 

[Roboramma]

Rest is somewhere else. You're wrong. Physical chemistry encompasses more than quantum mechanics. It also includes thermodynamics, electrochemistry, and the like. If you want to believe in a Theory of Everything that allows physicists to model everything that chemists do, will do or know, you are entitled but it doesn't exist yet and probably never will. I'm an analytical chemist, I know QM and more than how to make molecules come together.

He didn't say anything about modelling everything chemists do. He said that the complex interactions that chemistry describes are just the interactions of atoms, and the way that atoms interact is described by physics.

When two atoms interact, their interaction will happen in a way that physics can describe. When more than two atoms interact they must necessarily be following the same rules.

Maybe there is some part of chemistry that isn't based on the interactions of (many) atoms - if so please be specific about what it is, because I'm having a hard time imagining it.

 

[Slimething]

He didn't say anything about modelling everything chemists do. He said that the complex interactions that chemistry describes are just the interactions of atoms, and the way that atoms interact is described by physics.

And I wrote that physics has yet to advance to that stage. Now, you return with the presumptive statement that interactions between atoms can be described by physics. That is not so. I challenged him and now I challenge you to illustrate one chemical reaction, describe the products (odor, color, melting/boiling points, etc.) Choose any reaction you want. I'll wait. Let me know when you're done.

When two atoms interact, their interaction will happen in a way that physics can describe. When more than two atoms interact they must necessarily be following the same rules.

What you are describing is chemistry, not physics. Please attend to challenge above.

Maybe there is some part of chemistry that isn't based on the interactions of (many) atoms - if so please be specific about what it is, because I'm having a hard time imagining it.

Well, I left a big, big hint in the post you replied to. There are many. In analytical chemistry, we exploit the characteristics of a compound or class of compounds to define its composition or its concentration. Physical chemists (if you believe that the word "physical" in a title necessarily involves physics, you should go back to physical education) elucidate the nature of the electronic state in atoms and molecules. Formulation chemists study the properties of mixtures, as do metallurgists.

An earlier post made the excellent point that non-chemists see chemistry as all organic synthesis. That is a level of over-simplification that I find extraordinary in an educated individual. It's tantamount to my believing that physicists only study the motion of boxes on inclined planes.

 

[Roboramma]

And I wrote that physics has yet to advance to that stage. Now, you return with the presumptive statement that interactions between atoms can be described by physics. That is not so.

Okay, point taken. I phrased things poorly. What I am trying to say is that all the forces involved are known. At least the important ones.
From this we can conclude that if we could analyse these forces well enough we could model the interactions. Niether I nor anyone else is saying that we actually can do so, just that the forces involved are known.

If you aren't suggesting that there is some other force at play, then I don't see how chemistry isn't reducible to physics. Will any particle be affected by any other in a way that contradicts known physics?
Or are you suggesting that this is some other force involved.
This is a serious question, I don't know that much about either chemistry or physics and am hoping to have my own errors shown to me.

I challenged him and now I challenge you to illustrate one chemical reaction, describe the products (odor, color, melting/boiling points, etc.) Choose any reaction you want. I'll wait. Let me know when you're done.

As I said I phrased things poorly. My bad. But I make no claim to be able to do that, or that anyone can. Obviously we are very very far from that.

What you are describing is chemistry, not physics. Please attend to challenge above.

Point taken.

Well, I left a big, big hint in the post you replied to. There are many. In analytical chemistry, we exploit the characteristics of a compound or class of compounds to define its composition or its concentration.

Are you suggesting that the characterists of a compound don't depend on the characterists of the atoms that it's made of and the way that those atoms interact, or that the way that those atoms interact is not itself dependent upon physics?
If physics doesn't describe the chemically relevent characteristics of atoms (I think it does, but whatever) are they not dependent upon the characteristics of the particles that make up those atoms and the way that they interact?

Physical chemists (if you believe that the word "physical" in a title necessarily involves physics, you should go back to physical education)

Thanks for the advice. I don't.

elucidate the nature of the electronic state in atoms and molecules. Formulation chemists study the properties of mixtures, as do metallurgists.

Again, see what I said above.

An earlier post made the excellent point that non-chemists see chemistry as all organic synthesis. That is a level of over-simplification that I find extraordinary in an educated individual. It's tantamount to my believing that physicists only study the motion of boxes on inclined planes.

Well, as I don't pretend to be an educated person, just one who's trying to understand, I won't pretend to even know what you mean by organic synthesis.

I'm very happy for you to explain things to me to the point that I say, "Oh! I get it now, there is something going on in chemistry that isn't just the interactions of particles." I'm arguing for the case that I think is true simply because that seems like the best way to get you to explain yours.