Empty “Analytic Metaphysics”: Michael Loux’s Vicious Circle of Modal Properties

 

The American philosopher Michael J. Loux seems to be a master of playing games with modal terms — at least within this particular 2002 discussion of bare objects (i.e., within ontology).

Now it’s often been said that modal terms form a “closed circle” in that the definition of one term must include reference to all, some or at least one other modal terms (i.e., they’re necessarily interdefinable). And since I’m going to be sceptical about the use of modal terms (if only within the context of what Michael Loux has to say), here’s the English philosopher Bob Hale on the sceptic’s position on necessity and how it must bring in (at least part of) the aforesaid closed circle of modal terms or properties:

“It is difficult to see how his scepticism about necessity could be so much as expressed without employing the notion of possibility. And once a notion of possibility has been granted houseroom, the intelligibility of a correlative notion of necessity can hardly be denied.”

More particularly, Loux (as it were) fuses different modal terms (or properties) in that he believes that the acceptance (or use) of one must bring on board at least one other modal term (or property).

Just to cite another example of this modal (as it were) fusion, take Loux’s fellow American philosopher Alvin Plantinga. He also goes in for using modal terms together when he tells us that “some properties” are “necessarily essential to all objects”. (He offers us the examples of the properties self-identity and existence.) Plantinga also makes the statement that “a necessary proposition is just a proposition that has truth essentially”.

In the specific case Michael Loux tackles here, the terms “essentially”, “necessarily” and “contingently” are played around with. And these terms are played around with in the specific context of the ontology of bare objects (or bare particulars).

The words “essentially” has just been mentioned. It’s worth saying here that there is some dispute as to whether the word “essence” (or “essentially”) is a modal term and what its precise status is. (For example, E.J. Lowe argues that “rather than attempt to explain essence in term of necessity, we need to explain necessity in terms of essence”.) Some modal theorists claim that “essence” (or “essentially”) isn’t actually a modal term and therefore that it isn’t a modal property. However, Michael Loux himself strongly connects essential properties to the other modal properties. Yet, in terms of the passage above, one may have no problems with what Bob Hale says about necessity and possibility and still have problems with Loux’s shoehorning of essential properties into these modal domains.

Loux is committed to essential properties. And he — at least partly — arrives at this commitment via necessity. For example, Loux writes:

“[N]ecessarily everything has some properties essentially.”

Loux believes that this metaphysical fact (if we can use the word “fact” in this ontological context) is a way of “refuting” what he calls “anti-essentialism”. Here again Loux displays his closed circle of his modal terms. That is, according to Loux it is a necessary metaphysical fact that all things have at least “some” essential properties. (We also have some kind of non-Quinian modal universal existential quantification in the quote above. See here.)

What are Properties?

Michael Loux assumes (at least within the passages quoted) the existence of essential properties. And, from that assumption, almost everything else in his general argument follows.

For a start, if there are essential properties, then there must also be contingent properties. After all, the postulation of essential properties literally makes no sense without also postulating contingent properties. So, to paraphrase a well-known statement (usually about an entirely different subject), take the following:

If all properties were essential (or contingent), then no properties would be essential (or contingent).

(It must be said here that in the Leibnizean position on objects and their essences it is argued — at least by some — that all an object’s properties must be taken as being essential to it. See here.)

And in which way do such properties “belong” to objects? Do they “inhere” in objects? How, exactly, do these specific properties belong or inhere in objects? Within this context, what do those words actually mean?

Trivial Properties?

Michael Loux argues that “everything” has essential properties. (This isn’t the Leibnizean position that all an object’s properties are essential to it.) So which kind of properties must everything have? Loux firstly cites “trivially essential properties”. They’re

“properties like being self identical, being red or not red, being coloured if green and being either identical with or distinct from the shape of triangularity”.

Now I don’t mind saying here that I have a very strong aversion to these ostensible properties. Or, more correctly, I have a very strong aversion to them being used in philosophical arguments. Having said that, I don’t want to be a philosophical philistine about them. So perhaps there are profound logical and philosophical consequences to be had from accepting these properties. Then again, Loux may simply accept them because he believes that they are real (or that they have being)— full stop.

So what if the property having no properties (cited by Loux later) is not actually a property at all? Similarly, what if properties like being self-identical or being red or not red (two more examples from Loux) are not properties at all? This must depend on what properties are actually taken to be. In this sense, then, they’re surely abstract if they’re anything. That is, one can’t observe, touch, kick, smell, experiment upon, etc. the property being self-identical or being red or not red.

As stated, all this may entirely depend on what a property actually is. Or, more accurately, all this may entirely depend on what properties are taken to be in these very specific modal and ontological contexts.

From a cursory point of view, it can quickly be seen that trivial properties (of the kind that Loux accepts) must be infinite in number. After all, if there is the property being red or not red, then there must also be the property being blue or not blue. Similarly, if there is the property being either identical with or distinct from the shape of triangularity (an example from Loux himself), then there must also be the property being either identical with or distinct from the shape of a banana. Finally, if there’s a property being colored if green, then there must also be the property being an animal if a human being… and so on ad infinitum.

And then we also have weirder properties such as not being self-identical. And what about the conjunctive property being self-identical and being an apple?

Impure Properties

The American philosopher Albert Casullo refers to what he calls “impure” properties. These are similar — though not identical — to Loux’s trivial properties. He cites “being identical with individual A” as an example.

Now the property being identical with individual A (as well as other impure properties) is different to the trivial properties which Loux argues all objects must have; as well as being different to the properties that just some objects must have (such as being coloured if green). That’s the case because only one object can “have” the property being identical with individual A (at least according to the identity of indiscernibles thesis). Thus the property being the number 4 also fits into this category. Indeed Casullo states that “such properties are obviously unshareable”. Of course a property being unshareable doesn’t automatically make that property suspect. However, it may be suspect anyway.

Casullo himself uses the words “[i]mpure properties, if such there be”. That at the least hints at a degree of scepticism on Casullo’s part.

In any case, Casullo seems to countenance impure properties because he uses them as a means to another philosophical end. (In his case, it’s to show that “individuals [] are ontologically derivative from properties” — see note at the end of this piece.) So perhaps Loux himself is countenancing his own trivial properties for other philosophical ends too. In other words, fake, silly, trivial or impure properties are smuggled into these arguments in order to advance various philosophical arguments which are independent of these supposed properties. Clearly, Loux uses these properties to reject bare objects and to advance his own essentialism. (In Casullo’s case, he uses his impure properties to advance an argument against the bundle theory.)

To give one more example.

I mentioned Alvin Plantinga earlier and he too offers his own seemingly genuine property: existence. This subject has been well-debated in philosophy and Plantinga is fully aware of that fact. So he tells us that “[s]ome philosophers have argued that existence is not a property”. However, Plantinga himself believes that “every object has existence in each world in which it exists”. Here again I’ll only mention Plantinga’s philosophical position on the property existence in passing because it seems similar to Loux’s own positions.

Examples

Example 1

The following is a perfect example of Michael Loux seemingly fusing properties which are contingent with properties which are essential. He writes:

“[T]here is another property they [bare objects] have essentially — the property of having merely contingently the property of having no properties essentially.”

Apart from that passage being hard to understand and it being very strange (at least intuitively), here the terms (or properties) “contingently” and “essentially” are intimately linked to one another.

Loux is arguing here that a contingent property is “essential” to (in this case) a bare object. That is, the contingent property having no properties essentially is essential to the bare object which has that property. What’s more, that essential property is the very property having no properties essentially. Thus a property which is — at least initially — deemed to be contingent is shown to be an essential property. In other words, when an ontologist commits himself to an object which is bare, he’s also committing himself to an object which has no properties. However, Loux argues that this commitment to an object with no properties is an implicit and necessary commitment to that bareness itself being an essential property. It is essential because it’s deemed necessary (if implicitly) that a bare object be bare. And if a bare object is deemed to have no properties necessarily, then it must also have at least one property essentially: the property having no properties essentially.

Of course this may simply be Loux showing us that this position (on bare objects) leads to absurdity (or to a contradiction). That’s unless he’s actually arguing that a bare object has a property that is both contingent and essential. (His other conclusion is that there is no such thing as a genuinely bare object — and that’s precisely because it must have at least one property.)

As hinted at earlier, what if the believer in such a bare object doesn’t see having no properties as being a property at all? What’s more, if he doesn’t believe having no properties is a property, then (by definition) he won’t accept the modal having no properties essentially is a property either.

To go into more detail. Why does Loux stick the word “essentially” on the end of “having no properties”? If the ostensible property having no properties can — at least initially — be seen as being suspect, then the property having no properties essentially is surely an even more suspect property. Yet, of course, Loux is attempting to show us that the commitment to the idea that a bare object must have no properties is also to be commitment to accepting that such a bare object must have no properties essentially.

Thus, is the property having no properties essentially what Loux calls a “trivial essential property”?

Example 2

Michael Loux also asks this question:

“Does a thing with no essence have the property of being essenceless essentially?”

Here again it’s assumed that being essenceless is a property. And because Loux sees it as being a property, then it follows (as least in Loux’s own scheme) that the property being essenceless must be a property of some particular kind. That is, it must either be an essential or a contingent property.

Loux’s first question generates his next statement:

“If not, then apparently it [a bare object] could have had an essence [].”

Loux is arguing that if a bare object having no essential properties is a contingent metaphysical fact, then it’s also possible that this very same bare object could possibly have had an essential property. Thus it’s not necessary that this bare object is without essential properties. Indeed, as we’ve already seen, according to Loux’s scheme this bare object must have at least one property. Indeed that one property turns out to be an essential property!

Loux’s argument (at least here) is specifically about bare objects. However, it still shows us Loux’s fusion of modal terms; as well as his assumption that essential properties are real (or have being). Thus, from seemingly showing that bare objects must have at least one property, Loux then concludes that that at least one property could be an essential property. Taken together, then, Loux offers an argument against the bareness of bare objects; as well as an argument which supports (some kind of) essentialism.

Loux then goes one step further in his fusion of modal terms by bringing in necessity and possibility. He writes:

“[B]ut, then, on any plausible understanding of the notions of necessity and possibility, there is another property that is essential to [this bare object]— that of being possibly essenceless.”

Loux believes that he’s just established that this bare object could possibly have an essential property. Now he simply makes the obvious conclusion that this same bare object could possibly be essenceless. Here we have another property — being possibly essenceless. But what kind of property is that? It seems to be (to use Loux’s own word) trivial.

So Loux is attempting to show that it’s impossible for an object (even an ostensibly bare object) to be essenceless. Yet here he’s discussing the property being possibly essenceless. And of course the property being possibly essenceless can itself be seen as being an essential property!

As earlier, I would question the reality of the property being essenceless. What’s more, being possibly essenceless seems to be an even more suspect property.

Example 3

Michael Loux concludes by saying that

“[n]ecessarily every object has every one of these properties essentially”.

In this particular example of the vicious circle of modal terms we have Loux tying necessity to essence

Loux also tells us that that

“it is a necessary truth that every object has many such properties essentially”.

In other words, Loux has chosen properties that every object must “have”. Specifically, Loux says that every object must be self-identical, red or not red, etc. However, that doesn’t apply to his other example of “being coloured if green”. (Obviously, that property only applies to objects which are green.)

Having said that, Loux does provide us with essential properties which don’t belong to “every object”. He gives the examples of the properties being distinct from the number nine and being non-human. Clearly, the number nine isn’t distinct from the number nine. And humans can’t have the property being non-human.

Finally, Loux arguments are all designed to lead to the following conclusion:

“So it is impossible that there be any entities with no properties essentially.”

Loux’s position that bare objects must have at least one property arises because each bare object must have the property not having any properties. More relevantly, Loux is specifically advancing the position that the property having no properties is an essential property. That is, being committed to an object having no properties is, by default, also a commitment to it having at least one property: having no properties. This leads to contradiction and/or absurdity. Thus Loux concludes that bare objects — and all objects — must have at least one property. Not only that: all objects must have at least one essential property.

To sum up. Loux argues against the position that bare objects have no properties as a means to advance his essentialist position on all objects. That is, Loux believes that all objects must have at least one essential property. Thus Loux is advancing ontological essentialism.

Note:

Casullo’s argument is that the property being identical with individual A incorporates a reference to an individual — individual A. Thus individuals — not properties — seem to be primary.

Things Themselves are Numbers: Contemporary Pythagoreanism

 

In a simple sense, mathematics may be viewed as an extremely useful tool. The English cosmologist, theoretical physicist and mathematician John D. Barrow, however, holds a slightly different view. That is, he posits the view known as Pythagoreanism, summing up the relationship between mathematics and physics in the following way:

“By translating the actual into the numerical we have found the secret to the structure and workings of the Universe.”

So the Universe and its parts are assigned numbers… Or are described by numbers… Or are captured by numbers… Or are explained by numbers… Or are (to use Barrow’s own words) translated into numbers.

But what does all that actually mean?

Sure, if Pythagoreanism holds at least some water, then it’s no wonder that so many people have also believed that through maths (as Barrow puts it) “we have found the secret to the structure and workings of the Universe”. But even here there’s a non-Pythagorean (as it were) remainder. After all, maths finds the secret of things which already exist — i.e., the “structure and workings” of the world. It isn’t actually being argued that these structures and workings are literally maths. The world is not itself maths.

… Or is it?

To the Pythagorean, the world and its parts are actually mathematical. This means that it isn’t that maths is simply helpful for describing the world — the world itself is mathematical. Indeed one must take this literally. Here’s Barrow again on the Pythagorean position:

“[The Pythagoreans] maintained ‘that things themselves are numbers’ and these numbers were the most basic constituents of reality.”

And Barrow then becomes ever clearer when he continues in the following manner:

“What is peculiar about this view is that it regards numbers as being an immanent property of things; that is, number are ‘in’ things and cannot be separated or distinguished from them in any way.”

Moreover:

“It is not that objects merely posses certain properties which can be described by mathematical formulae. Everything, from the Universe as a whole, to each and every one of its parts, was number through and through.”

It’s hard to grasp what the phrase “things themselves are numbers” even means. Can we say that reality and its parts are mathematics (as in the “is of identity”)? That reality and its parts are literally made up of numbers or equations? That reality and its parts somehow instantiate maths, numbers or equations?

And what does it mean to say that “numbers are in things”? Indeed there’s a problem here. If things are literally numbers, then how can numbers also be “in” things? In other words, how can numbers be in themselves? That would be like saying that cats “are in” cats; or that a dog is in the very same dog.

The Unreasonable Effectiveness of Mathematics

The important distinction here is that this isn’t about the “unreasonable effectiveness of mathematics in the natural sciences”. (In which we note the miraculous fact that maths is often a perfect tool for describing the world and then wonder why that is the case.) This is about (to use Barrow’s words again) “the Universe as a whole, [and]each and every one of its parts [being] number through and through”.

Thus description and being are two very different things.

Another way to describe the maths-world relation is to say that (as Barrow again does) that

“mathematics has proved itself a reliable guide to the world in which we live and of which we are a part”.

Yet here again, saying that mathematics is “ reliable guide to the world” is no more of a Pythagorean statement than saying that maths describes the world.

To be clear. A map of Essex is not actually Essex. The set of rules for chess is not an actual game of chess. (Though each game of chess is always — as it were — a variation on the rules of chess.) So it may well be the case that if we didn’t have a map of Essex, then we’d get lost in that county. Similarly, if we didn’t have maths, then we wouldn’t have a reliable guide to the world.

But what of that “miracle” that is math and its relation to the world?

The Hungarian-American theoretical physicist Eugene Wigner (famously) put it this way:

“The miracle of the appropriateness of the language of mathematics for the formulation of the laws of physics is a wonderful gift which we neither understand nor deserve. It is difficult to avoid the impression that a miracle confronts us here, quite comparable… to the two miracles of laws of nature and of the human mind’s capacity to divine them. The enormous usefulness of mathematics in the natural sciences is something bordering on the mysterious and… there is no rational explanation for it.”

Albert Einstein was similarly perturbed when he wrote:

“How can it be that mathematics, being after all a product of human thought which is independent of experience, is so admirably appropriate to the objects of reality?”

However, Einstein’s own conclusion appears to be radically at odds with Wigner’s when he continues with the following words:

“In my opinion the answer to this question is, briefly, this: As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.”

Despite those sceptical remarks from Einstein, let’s get back to the being I mentioned a while back.

The physicist and cosmologist Max Tegmark puts the contemporary case for (Pythagorean) being in the following very concrete example:

“[If] [t]his electricity-field strength here in physical space corresponds to this number in the mathematical structure for example, then our external physical reality meets the definition of being a mathematical structure — indeed, that same mathematical structure.”

To spell out the above.

Max Tegmark isn’t saying that maths is perfect for describing the “electricity-field strength” in a particular “physical space”. He’s saying that the electricity-field strength is a “mathematical structure”. That is, the maths we use to describe the electricity field is one and the same thing as the electricity field. Thus, if that’s the case, the “miracle of mathematics” is hardly a surprise! That’s because it’s essentially a situation in which that maths is describing maths. And if maths is describing maths, then the word “describing” is surely not apt word to use in the first place.

In any case, Tegmark gives us more detail on his position when he tells us that

“there’s a bunch of numbers at each point in spacetime is quite deep, and I think it’s telling us something not merely about our description of reality, but about reality itself”.

Yet Tegmark appears to contradict himself in the above. At one point he says that a field “is just [ ] something represented by numbers at each point in spacetime”. So here we have the two words “something represented”. Yet elsewhere Tegmark says that the field “is just” (or just is) a mathematical structure — the latter two words implying that all we have is number. To repeat: Tegmark says that the field is “represented” by “three numbers at each point in spacetime”. Yet he doesn’t (in this passage at least) say that the field is a set of numbers (or even a “structure” which includes numbers).

So perhaps there’s a difference between saying that “things themselves are numbers” (as the Pythagoreans did) and saying that the world is mathematical. (I may be drowning in a sea of grammar here.) The latter may simply state that the world exhibits features which are best expressed (or described) by mathematics. The former, on the other hand, says that the world literally is mathematics. But (as already stated) it’s hard to grasp what that even means.

Do you realise just how tiny strings are?

A Short

It’s hard to grasp just how small the strings of string theory are.

Strings are to contemporary physicists just as atoms were to the physicists of the 19th century or particles were to the physicists of the 20th century. In fact strings are said to be fantastically smaller than protons and neutrons. (See the complicating note at the end of this piece.)

… Or are strings really in the same boat as particles and atoms once were?

The American theoretical physicist and string theorist Brian Greene puts the problem in this way:

“Strings are so small that a direct observation would be tantamount to reading the text on this page from a distance of 100 light-years: it would require resolving power nearly a billion billion times finer than our current technology allows.”

It’s not surprising, then, that

“[s]ome scientists argue vociferously that a theory so removed from direct empirical testing lies in the realm of philosophy or theology, but not physics”.

So how can we make both philosophical and everyday sense of string theory’s strings?

As stated, the situation physicists find ourselves today can be compared to the situation physicists found themselves in the 19th century with atoms and with particles in the 20th century… Except that although atoms and particles were never directly observed at those times, they were, nonetheless, indirectly “observed”. More importantly, both atoms and particles did have results when it came to (to use Brian Greene’s word) “direct empirical testing”. That is, there were testable and observable happenings which (as it were) hinted at the existence of both atoms and particles.

Yet we simply don’t have that with strings.

Perhaps strings are, therefore, a mathematical contrivance. I say that because many string theorists (more or less) state the same thing. Take the words of the American theoretical physicist Michio Kaku. He wrote:

“My own view is that verification of string theory might come entirely from pure mathematics, rather than from experiment.”

Saying that string theory is hyper-mathematical isn’t to say that strings don’t explain anything. They certainly do. They both explain and unify a hell of a lot of things. However, none of that explanation or unification has anything to do with direct empirical testing.

Thus it is highly unlikely that a string — even in the (near?) future — will ever be observed. But what about the empirical testing of strings in the future? It’s hard to work out what exactly that could mean. How can something so fantastically small ever have an effect in — or on — an experiment?

Despite saying all that, Brian Greene himself has faith and hope.

Greene finds the views of sceptical scientists “shortsighted” or “at the very least, premature”. Yet Greene also acknowledges that “we may never have technology capable of seeing strings directly”. However, he nonetheless concludes that “the history of science is replete with theories that were tested experimentally through indirect means”. But which “indirect means” has Greene in mind for strings? He doesn’t say. (At least not directly after these statements.) It’s hard to imagine that something which would “require resolving power nearly a billion billion times finer than our current technology allows” could even provide indirect evidence. And that may be because (as already hinted at) a string is entirely the child of mathematical theorising. That is, a string is most certainly not the child of physical experiments — or even of any theorising based on physical phenomena.

Note:

One point that is never made entirely clear (at least not in popular science books!) is this: if what we take to be a particle is the instantiation of various levels — or types — of energy vibration of a string, then clearly strings can’t be either smaller or larger than a particle. (In the opening image, a quark is deemed to measure 10−16 cm; whereas a string comes in at 10–33 cm.) That’s because a particle actually is a vibrating string. Yet we have indirect physical evidence of particles, but no indirect physical evidence of strings at all.

 

Daniel Dennett vs. Roger Penrose: Strong AI

 A Short

A while back, the philosopher Daniel Dennett made it seem as if the mathematical physicist Roger Penrose took an immediate and emotional position against strong artificial intelligence (sAI). Indeed Dennett quotes Penrose as saying: “Somehow I’ve got to prove that this is wrong.” In other words, Penrose had non-scientific reasons for rejecting sAI… But is that actually a quote from — or even a paraphrase of — Penrose? I say that because Dennett uses the phrase “he thought” rather than “he said”. This may well be a simple slip of grammar on Dennett’s part. Though if not, then Dennett was simply guessing as to what Penrose thought. After all, Dennett can’t have known what Penrose thought unless he told him.

In any case, the main position that Dennett upholds is that strong AI is actually entirely in tune with both physics and biology; whereas Penrose’s position seems to be at odds with these disciplines. In Dennett’s own words:

“[W]hat [Penrose] has seen… is that the only way you’re going to show that the idea of strong artificial intelligence is wrong is by overthrowing all of physics and most of biology!”

This seems to make intuitive sense. That is, it seems that nothing in sAI clashes with either physics or biology. What Penrose argues, on the other hand, does clash with both. But there’s a problem here for Dennett. Physics (as physics) has nothing to say about intelligence, let alone about consciousness or even life. Thus when AI theorists talk about intelligence, consciousness and life, they’re essentially going beyond physics. So in that sense, strong AI isn’t really in tune with physics at all. Of course it can now be said that nothing in sAI actually and clearly contradicts anything in physics. That may be true; though it is hard to decipher how any talk (by AI theorists) of intelligence, consciousness or life could contradict anything in physics.

What about sAI squaring with biology or natural selection?

Dennett is on safer ground here in the simple sense that some evolutionary theorists do indeed talk about intelligence and life. And some even talk about consciousness. (Other evolutionary theorists have “no need for the hypothesis of consciousness”.)

In any case, Dennett is correct to argue that a “revolution in physics” is required in order to sustain Penrose’s scepticism about sAI. He’s correct primarily because Penrose has himself often talked about the need for such a revolution. Primarily, that revolution is required to square relativity theory and quantum mechanics (see here). However, this revolution also ties in with the revolution that’s required to get to grips with the nature of consciousness — in which both quantum mechanics and gravity, according to Penrose, must play a role at the level of the brain's microtubules (see here).

Jaegwon Kim’s Epiphenomenalism?

 A Short

How do we solve the problem of epiphenomenalism? (This is a position summed up well in this way: “Subjective mental events are completely dependent for their existence on corresponding physical and biochemical events within the human body yet themselves have no causal efficacy on physical events”.)

Here’s one possible way offered by the Korean-American philosopher Jaegwon Kim.

Kim argues that “we should not think of the relation of neural events to their supervening mental events as causal”. Moreover,

“supervening mental events have no causal status apart from their supervenience on neurophysiological events that have ‘a more direct causal role’”.

This means that this isn’t a case of a mental event at time t causing a neurophysiological event at time t 1. No: if a mental event (M) supervenes on a neurophysiological event (N), then both the mental event and the neurophysiological event occur at one and the same time. So we can’t say that mental event M causes neural event N if they occur at one and the same time.

This is like the H₂0-water case.

That is, we don’t first have a set of H₂0 molecules which cause water. When we have a set of H₂0 molecules, we also have water. H₂0 molecules, then, don’t bring about (or cause) water. H₂0 molecules constitute (or are identical to) water.

On Jaegwon Kim’s account, we both can and cannot say that mental events are epiphenomenal. We can say that they’re epiphenomenal in that if mental event M occurs at one and the same time as N, then it can’t be epiphenomenal. More accurately, if M “inherits the causal power” of N (or if it “rides piggy back” on N), then it both has causal power and is not epiphenomenal. On the other hand, if M is indeed riding pigging back on N, then we can see it as being epiphenomenal. But, again, if M and N occur at one and the same time and are intimately connected, and if M also inherits the causal power of N, then in what sense is M truly epiphenomenal? (Perhaps this is simply a matter of taste or grammar.)

But if we tie M and N so closely together, aren’t we also saying (or implying) that M literally is N (as already hinted at with the H₂0-water example)? That is, that M and N are identical? Again, as with the epiphenomenal nature of M, both yes and no. From the outside, all we have is N and human behaviour. However, ontologically (or from the inside), M is clearly not identical to N. Again, from the first-person (or subjective) point of view, M is not a physical event. From the third-person point of view, on the other hand, M doesn’t factor at all except in terms of behaviour and “verbal reports”. M alone is also (according to the American philosopher Donald Davidson) incapable of falling under any natural laws.

References

Kim, Jaegwon, ‘Multiple realization and the metaphysics of reduction’ (1992).
 — ‘Mental Causation’ (chapter 6) in his Philosophy of Mind (1996).