We have studied the Physical Model and the Mental Model, recognizing that the models are built upon two different sets of entities. The Physical Model is based upon primary physical entities (accessible to everyone and measurable), and the Mental Model is based upon primary mental entities (accessible to only one person and not measurable).

But we should always keep in mind that the Physical Model and the Mental Model are two different Models that can be used to model the same "Reality," referring to "Objective Reality."

(Remember that what we mean in the Objective Model by "Reality" is what is completely hidden behind that curtain, that we have no access to and will never have access to, other than the development of our models of it that allow us to predict what is going to happen, including what is going to happen if we do certain things. Essentially, Reality, or Objective Reality, is an entity constructed by definition only to explain why we are able to predict anything at all. It is the assumed "reason" why modeling is possible. This "Reality" is to be distinguished from what we usually mean in the Subjective Model by "reality" (Subjective Reality), namely, what we imagine and anticipate finding, i.e., perceiving, when we round the curve in the road, as well as what we are perceiving now, there being no basic difference other than whether we are perceiving it now.)

If we decide to study "the tendency toward aggression," we can use either the Physical Model or the Mental Model. We can study the processes in the brain that produce aggressive behavior, including things about the limbic system and neurotransmitters. But we can also understand the role of beliefs acquired through past experiences on the experiencing of anger, as modified by beliefs about social expectations, imagined consequences of acts, etc. The first way of studying is by using the Physical Model. The second way of studying is by using the Mental Model. But we will run into trouble if we try to combine models, such as trying to determine the relative contributions of dopamine release and attitudes toward revenge in the tendency toward aggression.

It is important to realize how we obscure the issue as to which model we are using by using similar words to mean different things and different words to mean similar things. For example, let us use "anger," and (simplifying) "amygdala activity" as our mental and physical entities, respectively. When this relationship is being talked about among scientists, there is not the assumption that anger is "causing" the amygdala activity or that the amygdala activity is "causing" the anger. The nature of the relationship between the two is generally not part of the discussion. Instead, anger and amygdala activity are considered to be two ways of talking about the same thing. Anger is considered to be the entity (in "Objective Reality") from the viewpoint of the person who has it and amygdala activity is considered to be the same entity (in "Objective Reality") from the viewpoint of the person seeing and talking about the brain of the person who has it. This entity (in "Objective Reality") needs a name. The simplest name to use is "anger." "Look at the amygdala. Anger is being produced." But that is not the only possibility. One can also use some terminology from the Physical Model to refer to the same thing, an example being "amygdala hijack." "She is feeling amygdala hijacked," or "He is getting a lot of dopamine out of that experience." Thus, one can obtain the vague impression that one is dealing with one Model rather than the other Model, because a word is taken from one Model and used metaphorically in the other Model.

Now the picture that is portrayed by the Physical Model (which has given us such amazing capability because of its ability to rely upon measurement and therefore produce highly accurate prediction) is sometimes, as we have said, referred to as the "physical world." There is a fair amount of recognition that mental entities do not have a clear place in that Model, if any place at all.

The Mental Model produces a picture referred to occasionally as the "mental world." It helps us to empathize with each other and to work at optimizing the quality of our subjective experience through improved interaction with others based upon that empathy. We learn how people think about things, and what they feel about them, and we make use of that knowledge in how we relate to them. Much of that knowledge (set of accurate beliefs) comes about in the development of the Subjective Model, of course, but the Objective Model, more specifically the Mental Model, carries us much, much further, as we learn to give up our stereotyped thinking about individuals and as we learn to a much greater extent "what makes people tick," that is, what the rules are that describe the interactions of entities in a person's "mind." With this additional knowledge, we can develop a much greater ability to help (or of course "manipulate" or "control") people. The psychological sciences contribute substantially to our capabilities.

There is very little actual use made of the terms, "physical world" and "mental world," but you may notice that the word, "world," usually refers to "all there is." So there is recognition among people, to a certain extent, that one can look at these two "worlds" separately, as two separate "totalities." In our discussion here, such reference would be to the Physical Model and the Mental Model, each with their somewhat overlapping lexicons.

What happens, though, is that there is an understandable desire for, and belief in the appropriateness of, there being just one "world." So it is quite understandable that we would take the Physical Model and the Mental Model and try to make them into one Model. It would seem most appropriate to call this sought-after, unitary Model the "Physico-Mental Model."

Now let us review what we mean by "world." We generally mean all the entities in that world and all their tendencies to interact. In fact, we seek to learn the rules according to which those interaction tendencies occur, because that is what allows us to predict what is going to happen, including what is going to happen if we do a particular thing. That ability to predict by use of a model is the defining function of a "model."

So in the "physical world" modeled by the Physical Model, there is assumed to be some potential interaction among some or all of the entities in that world, according to some rules that we will hopefully keep discovering (and maybe one day will have discovered completely). And we can say the same thing about the Mental Model, though rather less confidently. We do believe that the various mental entities have various effects on each other, such as our recognizing that certain thoughts cause certain feelings, and that those thoughts and feelings cause certain decisions to be made, and we do recognize that there is a certain amount of predictability regarding these interactions (and thus the existence of some "rules" that are being followed, at least to some extent, in those interactions), enabling us thereby to "understand" one another.

Now a problem does come about in trying to actually isolate these two Models, because our attention is often drawn to both primary physical entities and primary mental entities at the same time. We see things (that others can see), and have thoughts and feelings about them (that others can't see) at the same time. We decide to do things (decision being a primary mental entity in the mental world), and observe ourselves doing them (seeing things happen in the physical world). It is not easy to focus attention only on entities in one of the two "worlds." So it is quite understandable that we would simply and naturally tend to combine them both into one. In fact, of course, we never even began with two separate, discrete "worlds." As was discussed earlier, our modeling is like the development of the gradual solidification of a fluid, with many, many small areas ("lumps") of solidification gradually merging with each other. So it is not surprising that teasing these models apart is such a difficult process, that does not come naturally.

But you could say, "Okay, I agree that we are putting mental entities and physical entities into the same "world," and maybe we shouldn't, but if we shouldn't, why shouldn't we? Why is that obviously a wrong thing to do?"

You remember that we can have multiple models of any particular thing. But what we can't do (without producing problems) is try to take two different models of the same thing, the two different models being made out of different materials, and merge them together into a single model. We can't take a picture of a car and a plastic model of a car and successfully merge those two models into one.

Now we have to be aware of a subtle difference in our terminology.

We have indeed talked about the merging of separate models into one model by virtue of finding that all the entities and their interactions that are described (modeled) by each of those models are still described (such that accurate predictions can be made) with a more comprehensive (and perhaps even "simpler") model, that explains why both of those models work. This is the merging of "lumps" within the "modeling medium," or "fluid," to use our metaphor. This lump, made by the merging of two lumps, is a new, or third, larger lump.

But what we are talking about now is the modeling of any particular "thing," with the attempt to take two models of that thing and without changing those models use both at the same time. With regard to the picture of a car and the plastic model of one, each one can lead to predictions as to what the "actual car" will be like if actually encountered, but it would be impossible to construct an object that would be a useful model of the car by sticking the piece of paper with the picture on it to the plastic model of the car. The resulting entity would not look like the "actual car" anymore. It would be a "mess."

But one could indeed choose a particular model of that car and transform it into a most comprehensive model, by adding into the model how the details of it could be successfully translated into the details of any of the other models of it. This would be the development of a new, higher level model that now included those rules of translation. It would not be just the glomming together of two or more kinds of models of the car as if no translation were needed. And again note that this higher level model would thus have to have those translational rules as a part of it, and as a more specific example, involving linguistic modeling, have rules that dealt with the fact, if so, that in both of the original models some words were used that actually had different meanings, dependent upon the model in which they were used.

To make this distinction clearer, we need to look at a possible example of the Physico-Mental Model. This has been presented early in this presentation, as something like the world as imagined to be like the physical world, involving space, time, matter, energy, etc., and the rules governing the interactions of those entities, but with additional but invisible entities currently floating around somewhere in that world, always or sometimes attached to certain collections of mass identified as "bodies," perhaps only human ones but more likely ones in addition to human ones, assuming that chimpanzees and cats have them, these floating entities being labeled variously as "minds" or "consciousnesses" or "spirits" or "souls."

And indeed when these entities are added into this (now) Physico-Mental Model, the predictability enabled by the Physical Model becomes disturbed, just like the addition of the paper picture of the car to the plastic model of the car made something that no longer looked like, or modeled accurately, the car. If these invisible entities have any effect on the physical entities in the physical world, then the equations describing the rules those physical entities seem to follow would be expected to be disturbed, and yet this has not happened, at least not yet, despite verifying these equations with exquisite sensitivity. So if these mental entities have no effect whatever within the physical world, what are they doing in the Model? The Model is better off without them.

But who would want to throw out mental entities from the Physico-Mental Model? That would be like throwing away either the picture of the car or the plastic model of the car, each one possibly being valuable in certain situations. So the Physico-Mental Model is a model that we imagine, just as we can imagine all sorts of things that are not necessarily possible or likely, but we do not really use the Model practically (i.e., to make important, accurate predictions), and it is basically a flawed Model. We may use it in our rhetoric, but not in our efforts to predict accurately. (We of course use it extensively in political and religious discourse, so it does have effects on us, but effects that do not have to do with accurate prediction, the primary function of the Objective Model.)

So we find incompatibilities within that Model. The effort to solve the "mind-body problem" is indeed the effort to find a comprehensive model involving all entities, and the Physico-Mental Model fails as a candidate for a comprehensive model that solves the "mind-body problem." But what, then, can be a solution?

Note that in a sense our model involving the Subjective Model, Objective Model, and Reality, making use as it does of "Objective Reality," that which is behind the curtain but makes our other models possible, is indeed a candidate for something like a comprehensive model, if indeed those translational rules can be discovered. We need to look more closely.

We talked about how it looked like one answer to the "mind-body problem" might be that mental aspects and physical aspects were really not "aspects," but just "manifestations" of the same thing. So that "same thing" would be, according to the Objective Model, what lies behind the curtain. That "thing" that "exists" in "Reality" is neither our primary physical entity nor our primary mental entity, which are only our models of what is behind that curtain. (And remember that subjective experience is also a model of what lies behind the curtain, even though we don't think this way within the Subjective Model, which uses a "Subjective Reality" that is different than Reality, or Objective Reality, as the terms are being used in this presentation.)

And remember that two different models of the same thing may not necessarily be modeling the same properties of the thing being modeled, so that one model may give us certain abilities to predict whereas another model may give us different abilities to predict. We may be able to tell certain things about a car from its picture and other things about it from a diagram of it or a plastic model of it. And indeed, when talking about certain things, we may find the Physical Model more helpful in certain situations, and the Mental Model more helpful in other situations. We do know that there are (different) places for Newton's laws, relativity theory, and quantum mechanics, even though they cannot so far be combined successfully, a higher level theory being much sought after currently. (And again remember that the Subjective Model is what we are using all the time, whether or not we are also using one of the Objective Model models.)

We do sort of have a "crosswalk" between the Physical Model and the Mental Model, and that could be called (erroneously) the "correlation" between physical and mental entities. The error is clarified by remembering that correlation is a relationship between measurements, and there can be no measurement of primary mental entities. What we instead measure when we attempt to measure "mental things" are actually just their presumed "correlates" within the Physical Model. These "correlates" are not actually correlations, which are limited to the Physical Model where measurement is possible; instead, these "correlates" are essentially indeed just assumptions, beliefs assumed without legitimization, but found to lead to somewhat accurate predictions.

So we say that a particular primary mental entity is "whatever the person is experiencing" when he or she reports experiencing a particular entity (using a particular label, or word, such as anger, image, or thought). And to model that within our own subjective experience, we use images that we have assigned the same labels to.

We say we are talking about the person's subjective experience (his or her primary mental entities), but we are actually "dealing with," for example measuring, only the person's reports of that experience (or perhaps the results of examinations, such as imaging, of the nervous system or various markers of what is going on within that nervous system such as certain materials in the blood or spinal fluid), and thus ultimately only primary physical entities, not primary mental entities.

So you can see that this presentation of our modeling processes, our model involving the Subjective Model, the Objective Model, and Reality, is a candidate for the model that indeed integrates at a higher level the Physical Model and the Mental Model, and thus solves the "mind-body problem." Well, that may still not be very easy to see, so let's review and clarify.

Remember first that the "mind-body problem" is a problem that arises during the course of the development of the Objective Model. We are not bothered at all by anything we could call the "mind-body problem" if we never go beyond our Subjective Model. No other species is likely to be bothered by this problem, no other species having the capability to develop the Objective Model (unless to a very tiny, rudimentary extent, as when one chimp learns from another chimp, by watching, how to do something).

And what we have found to be our basic assumptions about the Objective Model are that we have the Subjective Model which is a Model of what lies behind the curtain, called Reality (Objective Reality), and we have the Objective Model, which is an add-on Model of that Reality that increases the quantity of our beliefs and makes some of them extremely accurate compared to those within the Subjective Model. And we remember that the "material" out of which those two Models are made, namely, primary mental entities, has to be different from what lies behind the curtain. Reality is stranger than anything we can imagine. What we can imagine is determined by the structure of our brains, not the structure of Reality other than whatever that structure of our brains "really is" behind the curtain.

So again, although our models within the Physical Model and the Mental Model are all made of the same "material," we know that that material has been found to be inadequate to create models that actually work precisely, obviously within the Physical Model, in which we are driven to the point of having our models be only mathematical equations modeling the relationships (equal, greater than, less than) between measurements. It is impossible to imagine (e.g., visually) atoms and space and time to be the way our measurements indicate them to be. There is nothing completely like that within subjective experience, even subjective experience that consists completely of imagination.

We should note, by the way, that it would not be appropriate to say that that which lies behind the curtain causes the two different kinds of models (primary physical entities and primary mental entities). The "causation" itself exists behind the curtain. Our picture of the curtain, with the models on one side of it and something mysterious on the other side, is just a convenient way of visualizing something analogous (i.e., is just a model). Reality (Objective Reality) remains completely behind the curtain and is self-contained, according to this model. We do, nevertheless, use the concept of "causation" in our Physical Model and in our Mental Model, as well as, of course, our Subjective Model. The causation relationship is between or among entities within each of those Models, and that causation relationship is assumed to be a model of rules that what actually exists behind the curtain follows. ("Causation" was covered earlier in this presentation, in the chapter on "Causation and Explanation.")

We have to recognize that the Subjective Model and the Objective Model are two sets of models of the same thing, Reality (Objective Reality). It is not that the Subjective Model is a model of the Objective Model, or that the Objective Model is a model of the Subjective Model. It is true that there can be some success in cross-walking between the two models, but not entirely. What we come up with in the Objective Model can be quite different than the way things seem to us within subjective experience. Sometimes they are the same and sometimes they are different. The more the Objective Model gets developed, however, especially as seen in the Physical Model, the more the discrepancy becomes evident. Things are not as they seem, we are told.

To a certain extent, since perception within subjective experience is a model of the same thing that the network of enhanced neuronal connections in the brain is, namely, whatever is behind the curtain, then it is not surprising that one can be used to predict what the other will be, meaning that it can be used as a model of the other to some extent. Reported subjective experience can make us believe that certain things are happening in the brain of the reporting person, and we can also imagine (model with entities within our own subjective experience) what the subjective experience of a person might be like, given our knowledge of what is going on in his or her brain, but we could be wrong. Models only work to a certain extent, anyway, and being imperfect does not render them useless.

But if whatever is going on behind the curtain involves a person having an hallucination of a house, then what is in the brain of that person is somewhat different than what one would assume was in his or her brain if one did not know that what was happening was an hallucination. So when the hallucination is taking place, it does not present, to the individual having it, an accurate model of what is happening in the physical world, despite his or her belief to the contrary. So, again, subjective experience (the Subjective Model) is not a completely reliable model of what would be found in the Objective Model. And that, indeed, is why the Objective Model is so extremely valuable to our species, adding greatly to the number of our beliefs and to their accuracy, or ability to predict and therefore to do. The Objective Model is not just an alternative Model; it is an important, corrective add-on to the Subjective Model.

So if we do believe that this new model, the one having been elaborated on in this whole presentation, is indeed an improvement over the Physico-Mental Model, and we wish to give it its own name, then my choice, for this presentation, would be the Tripartite Model, the model that is completely made up by three discrete entities, the Subjective Model (subjective experience and beliefs about that subjective experience acquired from the subjective experience alone); the Objective Model (the growing set of agreed-upon, by all those in the position of having an opinion, beliefs acquired objectively, independently of subjective experience other than the subjective experience of agreement with others regarding the symbolic modeling of those beliefs, enhanced to a great extent by the rules of logic and the rules of evidence); and Reality (that which is assumed to exist that makes it possible for any models to work, that is, makes predictability possible, but manifests itself in no other way). And of course these Models, and the Tripartite Model, exist by definition only.

But there is one extremely important conclusion to be drawn within the Tripartite Model.

The Objective Model, we must always remember, is basically created by agreement, ultimately agreement achieved by pointing. We have talked about our agreeing about many entities and situations in which we are using linguistic models of entities that cannot be pointed to. If the Objective Model is indeed ideally a completely internally consistent model, then all of the beliefs within it should be consistent logically with beliefs about those entities that can indeed be pointed to. Those, of course, are the primary physical entities, existing within the physical world.

Therefore it is extremely important to recognize that the Mental Model, with its utilization of mental entities, is ultimately another way of modeling the physical world .

So, despite how we talk, and even think (using the material of our subjective experience), the entities within the Mental Model are just "shorthand" for whatever is going on in the brain in the "physical world." We don't have to think that, or be aware that, we are "really" talking about what is going on in the brain when we talk about thoughts, feelings, etc., but whenever we become really serious about having a well-founded, internally consistent, comprehensive Objective Model, we must recognize that it is built upon the Physical Model, wherein lie the sciences.

Almost all of the time (actually all of the time) that we are using the Objective Model, we are doing some highly specific modeling that does not involve "all that we can objectively know." Ignoring this "reductionism," to use a pejorative noun to describe something actually very valuable, is therefore fine for most of what we do.

But when we are trying to solve our biggest, most perplexing problems, for which agreement and accuracy of what we are agreeing to are so very important, then we certainly do not want to ignore what would be a basic flaw in our modeling processes. So I ask you to try to really understand, and, if what I am saying seems correct, try to develop a confident awareness of, this component (unavoidable "reductionism") of the Tripartite Model.

But now we need to move on to a discussion of specific problems produced by the Physico-Mental Model, so that we can achieve, ultimately, the solutions to the problems that keep us from accomplishing so much more in the way of cooperation and attainment of a good quality of life.