A Thomistic Approach to Chemistry

Hi @vjtorley, @structureoftruth, @jongarvey, @Eddie and others listening,
So I just came back from the 4-day symposium on Thomism and modern science, which focused heavily on the philosophy of chemistry. I’m not yet an expert on A-T philosophy, but I think I’m getting better at it.

Substantial change and the cone of possibility

We talked about this question (and variants of it). The best explanation that I got (inspired by Fr. James Brent, O.P. and Jordan Haddad): you, Vincent Torley, being a physical human being, consists of secondary matter, i.e. prime matter which has substantial form. Thus your potentiality is limited by actuality. This means that while you do have the capacity for substantial change, you only have a limited number of things that you can substantially transform into within your “cone of possibility”. Now, in principle an external cause with infinite power (i.e. God, who is pure actuality) could act upon you and substantially turn you into a raccoon or car. But if what we have are only natural causes with limited actuality, then you are stuck within that cone of possibility. You can only transform into a corpse when you die.

The composition of water

The next topic concerns what water is. Is water composed of H2O? First, I’d like to narrow down and clarify the scope of the problem from water to H2O molecules. In a random body of water, there is H2O, but also other free radicals and other molecules, so this would confusing. Instead, we’re going to ask a simpler question: do hydrogen and oxygen exist actually or virtually in an H2O molecule?

The Thomistic answer is usually the latter, as Thomists tend to be against chemical reductionism. Chemistry is not a strict result of the laws of physics. I found out that this is by no means a minority or fringe position among philosophers of science, even those who are not Thomists. This is because there are several problems with reductionism, as detailed in this SEP article (section 6) and this paper by Robert Bishop, Whence Chemistry?. In short, in general it is currently impossible to completely and exhaustively work out the properties of molecules from their constituent atoms, even if we’re only talking energy levels. A good test case is isomers, molecules which have the same chemical formula but different structure, causing them to have different properties. Currently, there is no way for a quantum chemist to calculate the properties of different isomers without manually inputting the chemical structure. Of course, perhaps someone someday will find a way to do so. But there seem to be serious conceptual obstacles if we only have QM. These issues and others are talked about in more detail in the Bishop paper.

Thus, hydrogen and oxygen only exist virtually in H2O, which is its own thing, with different properties than either hydrogen and oxygen. Now, there are some properties that water may have in common with either atom. But this reflects the reality that to exist virtually means to have the powers of hydrogen and oxygen affect (though not fully determine) the properties of H2O. Therefore, it is unsurprising that these commonalities exist.

Once this argument works, you can go on and argue that a body of water could be thought of as a single substance consisting of H2O molecules all existing virtually within it. Some properties of a body of water, such as surface tension, apparently do not make sense to talk about if you have only a few molecules of water. The existence of macro-level properties irreducible to its constituents points towards its constituents existing only virtually.

Next, Robert Koons was one of the main lecturers in the symposium, and he talked about his own specific views on the philosophy of chemistry. Some of his ideas are summarized in this paper we read: Hylomorphic Escalation: An Aristotelian Interpretation of Quantum Thermodynamics and Chemistry. He takes the view, common among Thomists, that only macro-level objects with thermodynamic properties exist. Elementary particles/fields and even atoms for the most part exist only virtually as part of a greater object. Koons’ paper gives a fairly persuasive argument that thermodynamics cannot be reduced to a collection of discrete, individual particles. But in general, one of the main reasons why Thomists are reluctant to think of elementary particles and fields as individual substances is because in practice, we almost never (if at all) find them existing by themselves (instead of as part of some other substance). Thus, Thomists tend take a more structural realist view (as Feser does) towards the reality of atoms, molecules, and elementary particles.

Now, I would not go as far as Koons and say that electrons, for example, are never a substance on their own - there are specific situations where you can trap individual electrons, for example. But for the most part, the vast majority of electrons we encounter daily are never encountered on their own. They do not have their own unity, but are always part of some atom in a solid or liquid with their own macro-level properties.

Conclusions

Overall, after this symposium I became more aware of the problems with reductionism and the plausibility of Aristotelian philosophy of science to solve some of these problems. Still, I had many unanswered questions, partially because many of them are active research areas for Thomistic philosophers of science. For example, it is not clear whether light is a substance (or perhaps the EM field which gives rise to it is). I realized that in many areas of physics, it is still awkward to interpret them with A-T philosophy. I think that much more work still needs to be done, even if there are many areas where A-T philosophy is clearly useful. It is indeed a puzzle to me why A-T philosophy seems useful to understand science holistically, but when actually doing and thinking about science, it’s just much easier to revert to an atomistic model of nature consisting of building blocks which form together into a bigger whole.

Most scientists would probably not appreciate the uses of A-T philosophy, as it is probably not going to be beneficial for the practice of science itself. (This is unsurprising, as it is the same case with philosophy of science in general.) You certainly can be a scientist and take the “shut up and calculate” or “I have no need of that hypothesis” approach. However, A-T philosophy gives a better philosophical explanation for why science is possible at all, for example with regards to the laws of nature, which prompted this thread in the first place.

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@dga471

Thanks for this useful summary, which is gratifying to me, at least, in telling me I wasn’t making nonsense up in my previous comments on the subject. And on one point I was vindicated, in that when I’ve suggested the chemical properties of compounds cannot be predicted from the constituent elements, there were those who denied it. That very fact ought to tell us that “something is going on.”

It seems to me that, in part at least, the answers to this are that dealing with substances holistically is intractable to the mathematical, abstracting methods of modern science. If a brain were, in fact, irreducible to the sum of individual “algorithmic” nerve impulses, then modelling it in simplified form would be minimally informative, and replicating it exactly impossible in practice. It’s a clear case of searching for the keys where the light is, rather than where you lost them. In fact, because the brain is so complex, one could search for reductionist explanations forever, without ever realizing that the whole approach is wrong.

The whole point of the AT approach, I think, is that a substantial form is such a unity, so a holistic methodology of some sort would need to be developed. The only specific example I can think of is that of Goethe (see here, which of course (like Thomism itself) was conceived at a much less developed state of science and has been largely ignored in the modern explosion of science.

In practice, it seems, science deals with the problems you raise largely by formulating a new, higher level, science: physics can’t predict chemistry, so you investigate chemistry empirically. If AT thinking is true, the conceptual error only comes from the assumption that, if someone gets round to serious work, the bridge from physics to chemistry will be found (an example you mention).

A more serious error would come from not taking the holistic form of chemical compounds seriously, eg by using the principle of reductionism to argue that water cannot have macro-structures, or that we can ignore the whole organism in, say, evolution and need explore only the molecules.

This subject has has many implications. For example, as I mention in one the blogs linked above, it brings insights into what are deemed “random causes” in nature.

Secondly, it suggests that much important knowledge can only be gained by the holistic functions of the mind (this was Goethe’s insight) - and that links in to the protracted discussions here about knowledge of God or morality requiring something more “intuitive” than deductive logic from evidence.

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Thanks for the report on that conference, Daniel. Very interesting!

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Who denied it? That seems to be well known.

Awesome! Philosophy of chemistry is a very small community compared to physics and biology, it’s good to see it getting some love.

This is a fascinating question. I would say that the hydrogen and oxygen actually exist in H20 . I’m not sure how that is exactly related to chemical reductionism, though. It’s my impression that reductionism (that chemistry is just physics) is the majority opinion in philosophy of chemistry, though I know it’s one of the primary questions in the field. If chemistry is not a result of the laws of physics, what laws does it result from?

What do you mean here by “manually inputting the chemical structure”? Chemical structure comes from physical laws (QM, etc.) so I’m a bit unsure of what you’re saying.

That water has different properties than hydrogen and oxygen, does not mean that hydrogen and oxygen are virtual does it? This view seems to depend on the idea that atoms have immutable properties, when we know that many properties of atoms (energy levels being a ready example) change with the environment. That a hydrogen atom within a water molecule behaves differently than a hydrogen atom in vacuum doesn’t mean it ceases to be hydrogen does it?

But again, bulk level surface tension arises from forces present at the microscopic level. Modern chemistry education is predicated on the idea that molecular structure, determined by QM, determines macroscopic level behavior. A few water molecules have the same intermolecular forces that bulk water has, so surface tension is macroscopic application of microscopic properties. I don’t understand why we would want to think of the water molecules in a beaker of water as “virtual”.

Doesn’t that fly in the face of statistical mechanics, one of the more useful fields of physics to modern day biology?

Overall, this Thomist stuff seems kinda nutty to me. :slight_smile:

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Instead of “better philosophical explanation”, I would prefer the term “pseudo-explanation”. I don’t think it actually explains at all.

Hi Jordan,
Thanks for engaging. You raise some good questions.

First, I’m not sure whether the majority of philosophers of chemistry hold to the reductionist position - the SEP article gives representative arguments for both sides. There are also differing degrees of reductionism - strong vs. weak and so on.

In any case, if one holds to a non-reductionist position (Thomistic or not), then that means that chemistry has a set of unique laws which are irreducible to that of the laws of physics. This does not necessarily mean that these laws violate the lower-level laws of physics, only that they are not derivable from the latter. The higher-level laws are “just there”; by definition, they cannot be explained in terms of other laws.

More specifically, Aristotelian philosophy of science is at its core opposed to the philosophy of atomism [1]. In the conventional reductionist picture, the lowest level “building blocks” of matter - atoms (or elementary particles, or strings) are the most fundamental and the entities that actually exist. Higher-level entities such as bodies of water and chairs and humans do not really exist as a single “thing” (or substance), but are only an aggregate of these atoms. Chemical laws are only aggregates of the laws of physics.

In contrast, Aristotelian philosophy reverses this bottom-up picture to take a top-down picture. Here, macro-level objects [2] exist actually, while their constituents do not “really” exist; they exist only virtually. This doesn’t mean that the Aristotelian denies the utility of modern scientific theories about the atom. Rather, she tends to take a non-realist approach to the reality of entities such as atoms and molecules. By non-realist, I do not mean instrumentalist; Feser for example defends a structural realist view of philosophy of science, where scientific laws capture something real about the structure of reality but not every entity in these laws actually exist.

Here, I’m only summarizing some of the points made by Bishop in his paper Whence Chemistry?. I strongly advise you to read that paper in entirety if you want to get a fuller picture of the non-reductionist (not necessarily Aristotelian) position. In particular, Bishop’s point is that the Hamiltonian for different isomers are identical, since they only contain different terms corresponding to nucleons and electrons (and interactions between them) added together, without mathematics to indicate the molecular structure:

image

No, Aristotelians do not think that atoms are immutable. But that’s precisely the point of Aristotelianism - a hydrogen atom can undergo smaller-scale changes while remaining a hydrogen atom. The basic metaphysical philosophy of Aristotle is that it’s a middle ground between the two extremes of Heracliteanism (where everything changes, there is nothing constant) and Parmenideanism (where nothing changes, and everything is constant). In Aristotelianism, sometimes things can change while remaining the same (this is called an accidental change), while at other times things do change so much to the point that they are a totally different thing (substantial change).

In contrast, philosophical atomists do tend to fall into the Parmenidean extreme, where (philosophical) atoms are thought of as immutable. If you’re a hardcore reductionist, then you would probably believe something along the lines that (chemical) atoms are really just aggregates of smaller, immutable fundamental particles (i.e. quarks and electrons, or even strings) which are rearranging themselves according to some immutable laws of nature.

Going back to the question of H2O. As you asked, does a hydrogen atom cease to be a hydrogen atom when it becomes part of H2O? Now, it just happens to be that most Aristotelian-Thomists tend to think that the answer is yes. But this is by no means logically entailed by Aristotelian philosophy. The answer depends, of course, on what it means for a hydrogen atom to be a hydrogen atom. Or, in A-T terms: when hydrogen reacts with oxygen to form H2O, does it undergo a substantial change? To answer this question we cannot simply argue from the armchair, but also take into account actual empirical data. Currently our data says that there seems to be properties of H2O which are not possessed by hydrogen at all when it is existing by itself. This seems to point to the answer that yes, hydrogen does undergo a substantial change when becoming H2O.

Now, if someone, whether through empirical investigation or argument, found out that the properties of water are indeed fully reducible to that of hydrogen and oxygen, then the Aristotelian would answer that yes, H2O is not a unified entity (or substance) by itself, but only an aggregate of hydrogen and oxygen, similar to two rocks being piled on top of each other. Note, however, that this wouldn’t disprove A-T philosophy, only change the A-T interpretation of H2O. It’s important to understand that A-T philosophy is not being offered here as a competitor to scientific method and facts and, but as a competitor to meta-interpretations of scientific facts.

At least on face value, it doesn’t. You should read the Koons paper to understand his argument. My very crude recap of his argument: in statistical mechanics, we commonly start by summing over a discrete number of states. At some point, we change our summation signs to an integral, taking the limit of an infinite number of states. Most of actual statistical mechanics is done by integrating, not discrete summing. Koons argues that when this switch (from sums to integrals) happens, a more significant change occurs - the transition from the micro to the macro-level, which has behavior irreducible to the micro-level. He advances arguments that you cannot obtain this continuum limit by simply adding discrete states, invoking the Stone–von Neumann theorem in the process.

Endnotes

[1] Note that I am referring to atomism as a general philosophy of science, not necessarily the modern scientific model of the atom that formed in the early 20th century with Rutherford, Bohr, etc.
[2] The majority of Thomists seem to only things as large and tangible as human beings and chairs exist, or molecules can exist. However, I don’t see in principle any obstacle against taking a hybrid view, where say, molecules exist actually but quarks and electrons (mostly) exist only virtually.

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It really depends on what you mean by explanation. If you define explanation as something that is necessarily reductionist, then of course A-T explanations would not be real explanations. But why so? I think that would be an interesting topic to discuss by itself in a different thread. Meanwhile, it’s good to also watch Feser’s lecture on the laws of nature that we discussed here and his argument as to why the Aristotelian view explains laws of nature better than the conventional “regularity” view, which is basically no explanation at all, period.

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It could be useful to briefly try to distinguish some different senses of reduction. This is me just thinking out loud at the moment:

One sense might be epistemic reduction: the thesis that we can deduce anything we might want to know about chemistry at the macroscopic level from underlying physical laws at the microscopic level. This seems impossible for us given the required computational complexity and the uncertainty principle, not to mention the measurement problem of QM - but whether it is in principle impossible may depend on whether other kinds of reduction hold.

Another sense could be called ontological reduction: the idea that the chemical substances that macroscopic things are made of are nothing more than some arrangement of extrinsically related fundamental physical entities (e.g. quarks and leptons). The Aristotelian-Thomistic approach is ontologically non-reductionistic: things are more than the sum of their material parts, since there is also their form which exists objectively and is irreducible to the mere arrangement of and extrinsic relationships between the matter which things are made of.

I’ve been reading a book recently (while waiting to get a hold of Feser’s Aristotle’s Revenge) called Material Things by Steven Duncan. (Not light reading by any account, but I recommend it if this thread interests you!) His version of non-reductionism is a little different: while he holds that chemical substances have form irreducible to the arrangement of their microscopic constituents, he also says that form is emergent from, and supervenes on, the structure of the microscopic constituents. Maybe that could be called weak ontological non-reductionism rather than strong (the difference possibly being lack of top-down causation - Duncan seems to deny top-down causation, at least for merely material things).

Duncan also points out that a lot of description and explanation can only happen with recourse to the macro-level: there’s no way to describe and explain (for example) what a baseball is using only the language of physics. (Describing it as “particles arranged baseball-wise” always ends up smuggling in something from the macroscopic level; he says something similar about chemical substances as well, not just recognizable objects.) Perhaps this could be called explanatory non-reductionism. This form of non-reduction probably holds; I am not quite satisfied that it is a sufficient condition for ontological non-reduction, however.

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But that’s not really right is it? Hydrogen isn’t hydrogen because of some total number of properties that are hydrogen-like and if enough of those properties are missing it ceases to be hydrogen. Hydrogen is hydrogen because it is an atom with a nucleus composed of one proton. Oxygen is oxygen because it has a nucleus with 8 protons. We can distinguish between H2O and neon, even though both have the same number of protons and electrons, I don’t know how that could be without H and O being real within the water molecule. Of course the hydrogen and oxygen atoms change when they form water but I have a hard time understanding how that makes them virtual. We can easily reform the hydrogen and oxygen from water, for instance.

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Here’s how Steven Duncan, as far as I understand him in Material Things, would describe the situation - it is slightly different from Feser’s take. The substance hydrogen is composed of matter (H2 molecules) and particular form (the arrangement or structure of those molecules that makes them a gas, lets say, along with irreducible macroscopic properties like temperature, pressure, colorlessness, etc - note the SEP article says there are difficulties even with the reduction of thermodynamic properties like temperature). H2 molecules are themselves composed of H atoms and a form, though Duncan suggests that at the level of molecules that may just be an accidental form rather than a substantial form; and so on further down. For Duncan, the H2 molecules (and the H atoms in those molecules) really exist within the substance hydrogen as the matter underlying that substance.

Similar story with the substances oxygen and water: composed of O2 and H2O molecules respectively, together with appropriate forms. The substance water really contains H atoms and O atoms within its H2O molecules - but it only virtually contains the substances hydrogen and oxygen, because the substantial form of those substances is absent, although the matter required to make up those substances is present.

I like this better than Feser’s account.

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I’m not a reductionist, so that’s not my reasoning.

I went back and listened to Feser in full.

Sorry, but I am not a Feser fan.

He starts with a theological account of laws (he calls that divine command theory). And he rightly rejects that. However, his deep theological assumptions are implicit throughout the rest of his talk. I’m sure Feser would deny that, but it is clear to see.

In his discussion of the Aristotlean approach, his theological assumptions show up as assumed essences. He gives no explanation of where essences come from. It seems just the kind of implicit assumption that would come from theology. The Aristotlean view is not a real explanation if it depends on unexplained essences.

A little earlier, arguing against Sean Carrol, he gives an extraodinarily bad argument for PSR.

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But I guess I don’t see how this matter/form distinction matters, or how we would even know. A molecule’s form depends on its matter, they don’t seem independent.

If it’s not already evident, metaphysics is by far my least favorite area of philosophy. It just doesn’t make much sense to me and I have a hard time seeing the use for it or how it could really make much of a difference.

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There are different approaches to metaphysics. For example, scientific metaphysics resists intuition and a priori reasoning, and instead emphasizes using only scientific results and scientific methods for problems that could be called metaphysical, such as the nature of free will, of causation, of the laws of nature. Such an approach in no way implies a reductionist ontology; indeed many of these philosophers are non-reductive physicalists.

But even among metaphysicians who accept a greater role for a priori thinking, starting with Thomist intuitions is only one possibility in analytic metaphysics.

Regardless of their position on intuition and a priori reasoning in metaphysics, I believe most of the philosophers agree with Daniel’s point that

So if these various metaphysical approaches have no scientific consequences, is there an independent set of standards for selecting the right approach to metaphysics? I suspect not. Instead, I think people aim for reflective equilibrium, and so accept a metaphysics which is consonant with their overall worldview of how our reality came to be and how we find meaning in living in it.

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Even if metaphysics makes little difference to the practice of science, it does play a role in how scientific theories are interpreted. I certainly would say that fundamental physics needs a dose of clearer thinking about metaphysics (John Bell is an example of a physicist who recognized this, evident in his writing about quantum foundations).

But even aside from science entirely, what we believe about metaphysics has important implications for how we understand the everyday world around us. If you believe the universe is devoid of telos, it becomes much more plausible to think that morality is all merely subjective. If you believe animals are soulless automatons as Descartes did, it makes sense to argue that there’s nothing at all problematic with vivisection. If you think that the body is nothing but a certain arrangement of atoms, it becomes easier to think of the mind as having such priority that subjective feelings are justified in trumping objective truths about the physical characteristics of said body, and it makes it easier to believe that human personhood is something separable from a human organism.

None of the above goes any way to showing whether this or that metaphysical theory is true, of course, but it demonstrates that metaphysics affects ethics. Metaphysics is, in that sense, an eminently practical area of inquiry.

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It is worth pointing out that modern science arose as a near total rejection of A-T philosophy in Bacon’s Novum Organum. It isn’t surprising to see A-T philosophers struggling to make sense of chemistry. It seems that at its core, A-T is incompatible with science. Perhaps not for being anti-science, but because science is anti-A-T.

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Also with noting that some A-T scholars (such as Feser) say that Bacon and the other early moderns give no good arguments for their rejection of Aristotelian philosophy, and that said rejection actually ends up creating an inconsistency in science hiding under the surface, which can only be untangled by undoing that mistake.

I’m afraid I haven’t read Bacon or Descartes to check on that claim!

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They have to say that if they are A-T. Sounds tautological. The justification for Bacon’s approach is that it worked where A-T failed for over 1000 years.

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Hi @dga471,

Thank you for your highly informative summary of the 4-day symposium you attended. I’d like to make a few brief comments on the topics you discussed.

…[Y]our potentiality is limited by actuality. This means that while you do have the capacity for substantial change, you only have a limited number of things that you can substantially transform into within your “cone of possibility”… You can only transform into a corpse when you die.

Yes, but my question was: why does my corpse (which has nothing in common with me except primary matter) have the same shape, size and mass as me? On an Aristotelian-Thomistic account of nature, there’s absolutely no reason why it should retain these particular properties, while having a different color (being pallid), a different texture (being rigid) and a different smell.

Chemistry is not a strict result of the laws of physics. I found out that this is by no means a minority or fringe position among philosophers of science, even those who are not Thomists… In short, in general it is currently impossible to completely and exhaustively work out the properties of molecules from their constituent atoms, even if we’re only talking energy levels.

I think you may be confusing ontological irreducibility with epitemological irreducibility here. The fact that we are currently unable to deduce the properties of molecules from their constituent atoms does not entail that the properties of molecules are not (in fact) determined by their constituent atoms. Think about it this way. Do you believe that God personally ordains the chemical properties of each and every isomer, on top of the underlying properties of their constituent atoms?

Now, there are some properties that water may have in common with either atom. But this reflects the reality that to exist virtually means to have the powers of hydrogen and oxygen affect (though not fully determine) the properties of H2O. Therefore, it is unsurprising that these commonalities exist.

I’m afraid this won’t do. According to Thomists, hydrogen and oxygen no longer exist in H2O. If they no longer exist, then neither do their powers, which are proper accidents of hydrogen and oxygen, and are therefore unable to exist in the absence of their underlying subject. Therefore, it is very surprising that these commonalities exist.

Once this argument works, you can go on and argue that a body of water could be thought of as a single substance consisting of H2O molecules all existing virtually within it.

Seriously? So if I’m out on a lake in a fishing boat, and I dip a cup into the water of the lake, that water undergoes a substantial change when I take it out of the lake? And if I pour it back in again, the new substance that existed inside the cup suddenly ceases to exist? Or again: if a puddle of water on the road partially evaporates, leaving two separate, smaller puddles of water, there has been a substantial change? And if it rains again and the two puddles merge into one puddle of the same size and shape as the old one, does the substance of the original puddle return, or is it a new puddle?

Can you now see why Scholastic philosophers were ridiculed by philosophers of the Enlightenment?

But in general, one of the main reasons why Thomists are reluctant to think of elementary particles and fields as individual substances is because in practice, we almost never (if at all) find them existing by themselves (instead of as part of some other substance).

I have two words for you: interstellar space. Here’s Wikipedia on the interstellar medium:

In astronomy, the interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays… By mass, 99% of the ISM is gas in any form, and 1% is dust. Of the gas in the ISM, by number 91% of atoms are hydrogen and 8.9% are helium, with 0.1% being atoms of elements heavier than hydrogen or helium, known as “metals” in astronomical parlance.

So all of these floating atoms, ions and molecules are accidents and not substances? And when a large number of hydrogen atoms coalesce (over millions of years) to form a star, that means that a large number of accidents, aggregated together, magically form a substance? On an Aristotelian-Thomistic account, this makes absolutely no sense at all.

For example, it is not clear whether light is a substance (or perhaps the EM field which gives rise to it is).

So when a piece of matter (i.e. a substance) encounters a piece of anti-matter (i.e. another substance), causing both to dissolve in a sea of photons, the result is an accident? Substance plus substance equals accident? This, I have to say, is gobbledygook.

I realized that in many areas of physics, it is still awkward to interpret them with A-T philosophy.

I agree.

Aristotelian philosophy reverses this bottom-up picture to take a top-down picture. Here, macro-level objects [2] exist actually, while their constituents do not “really” exist; they exist only virtually.

I will grant that some skepticism about the reality of atoms may have been justified during the time of Ernst Mach (who famously doubted their existence), but today, we have photos of them, for heaven’s sake. How can you have a photo of something that’s purely virtual?

The basic metaphysical philosophy of Aristotle is that it’s a middle ground between the two extremes of Heracliteanism (where everything changes, there is nothing constant) and Parmenideanism (where nothing changes, and everything is constant).

All well and good. But is it the only middle ground?

In contrast, philosophical atomists do tend to fall into the Parmenidean extreme, where (philosophical) atoms are thought of as immutable.

Well, perhaps fields are immutable. But you’re a physicist, so I shall bow to your superior wisdom on this point.

Daniel, I really appreciate all the trouble you’ve gone to. I’d like to leave you with a concluding thought. Take it from me, as someone who delved into modern Scholastic philosophy about 35 years ago: Aristotelian-Thomism and chemistry don’t mix very well. I think you sense that, too.

I think it’s fair to say that the Cartesian approach to biology leaves something very important out. Living things have a telos, and Baconian science ignores final causes. But only a tiny fraction of the cosmos is alive. In the field of chemistry, I’m sticking with atomism.

Hi @Jordan

That a hydrogen atom within a water molecule behaves differently than a hydrogen atom in vacuum doesn’t mean it ceases to be hydrogen does it?

Hear, hear!

Hydrogen isn’t hydrogen because of some total number of properties that are hydrogen-like and if enough of those properties are missing it ceases to be hydrogen. Hydrogen is hydrogen because it is an atom with a nucleus composed of one proton. Oxygen is oxygen because it has a nucleus with 8 protons.

Exactly!

A molecule’s form depends on its matter, they don’t seem independent.

I hadn’t thought of that point before, but it’s a very profound one.

Hi @structureoftruth,

His [Duncan’s] version of non-reductionism is a little different: while he holds that chemical substances have form irreducible to the arrangement of their microscopic constituents, he also says that form is emergent from, and supervenes on, the structure of the microscopic constituents. Maybe that could be called weak ontological non-reductionism rather than strong (the difference possibly being lack of top-down causation - Duncan seems to deny top-down causation, at least for merely material things).

The substance hydrogen is composed of matter (H2 molecules) and particular form (the arrangement or structure of those molecules that makes them a gas, lets say, along with irreducible macroscopic properties like temperature, pressure, colorlessness, etc - note the SEP article says there are difficulties even with the reduction of thermodynamic properties like temperature). H2 molecules are themselves composed of H atoms and a form, though Duncan suggests that at the level of molecules that may just be an accidental form rather than a substantial form; and so on further down. For Duncan, the H2 molecules (and the H atoms in those molecules) really exist within the substance hydrogen as the matter underlying that substance.

I have to say that Duncan’s account seems to make more sense than the Aristotelian-Thomistic account.

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Yet if Aristotelian philosophy (and I’m not bothering to defend Thomistic philosophy specifically, since I agree with @vjtorley that some aspects of it - the idea that living things are composed directly from prime matter and substantial form, for example - lead to absurdities) is not incompatible with the practice and findings of science, then the success of science since Baconian and Cartesian philosophy became dominant does not demonstrate the falsity of Aristotelian metaphysics, but at best that something like “methodological Cartesianism” is good scientific practice. And it seems, from the suggestions that Steven Duncan puts forth, that a broadly Aristotelian view is both entirely compatible with science and makes more sense as part of an overall worldview than the early modern philosophy. (Or at least, that there’s a good case to be made for that thesis.)

Also, I suspect that it is rather unfair to say that the Aristotelian tradition failed for 1000 years, as both downplaying what ancient and medieval scholars were able accomplish, and imputing values and standards on them that would have been foreign to their way of thinking. But confirming that would require a deeper dive into the history of science and philosophy than I can manage right now. :slight_smile:

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