Each of these two models is associated with its own lexicon, or language. There is of course much in common between those two languages. Both languages have the same rules of syntax. Both languages have many of the same words, spelled the same way, pronounced the same way, and meaning the same things. Most of these words are the non-technical words that make up the general vocabulary of a language, and are the majority of the words used in talking and writing.

However, there are words that are used in each of those Models that are almost never used in the other. The Physical Model makes use of "hydrogen" and "voltage" and "DNA" and "centimeters" and "cubical" and "Fahrenheit" and "neuron." The Mental Model makes use of "quaint" and "nostalgia" and "beautiful" and "doubt" and "worrisome" and "disgusting." We have already noted that the scientist, studying atoms, energy, etc., makes no explanatory use of "feelings," "thoughts," "fantasies," "wishes," etc., and that the person describing his own subjective experiencing of something does not use "atoms," "wavelengths," etc.

The language used in the Mental Model includes words that are labels for primary mental entities, everything that we can "directly" observe, or experience subjectively. The entities in this model to begin with are one's own perceptions, thoughts, feelings, memories, fantasies, wishes, fears, etc. These entities are everything that one's self can "experience." These "entities" are assigned words by us, such that with sentences including them one can cause others to understand (have accurate beliefs about), to some extent, oneself and what one is experiencing.

Initially, these words primarily are used to model subjective experience and the Subjective Model of subjective experience (one's beliefs about one's subjective experience). "I saw a beautiful garden, and inhaled the pleasing scents of the flowers, this producing for me a feeling of joy, accompanied by memories of my childhood garden and thoughts about how lucky I am to be able to experience all this. I believe that these memories are accurate," or "Ouch!! This is hot!"

Secondarily, however, these words will also be used as part of the Objective Model, referring to "subjective experiences that people have or can have," and additional words are used to label secondary mental entities, used to explain what people experience subjectively. This secondary use is what the field of "psychology" is all about. It is about, for instance, what "people," including oneself, may experience when they enter a garden, and it is about, for instance, how accurate or inaccurate childhood memories can be. It is about different ways of experiencing pain. This language is used in the Mental Model, to model that which is independent of any one person's subjective experience or Subjective Model.

The language used in the Physical Model includes words that are labels for primary physical entities, and is also used to model a world that is independent of any one person's subjective experience. This second language contains some words that are rather precisely defined so that communication will be as effective as possible, and the words stand for images that have aspects to them that are analogous to what are believed to be the properties of the entities being modeled. This has been discussed before, when we were considering the images associated with the concepts of molecules, atoms, sub-atomic "particles," force fields, electromagnetic "waves," etc. (Note that in the Mental Model, the "images" that are used are the memories of entities within one's own subjective experience, such as feelings, memories, thoughts, etc.)

Now a potential source of confusion arises from the fact that the languages contain certain words, similar in spelling and sound, that mean different things when used in the two different languages relevant to the two different models. The two different languages are used in two different contexts (two different kinds of situations, as parts of two different models appropriate for those situations), for two different sets of purposes.

The word "heavy" can be used to refer to the weight of something as measured on a scale on a particular planet or satellite and compared to a standard (Physical Model), but it can also refer to the experience a person has while holding something, that experience being different for people who are strong and weak (Mental Model). ("People with this illness experience heaviness of their extremities.")

This "different meanings for the same words in different models" actually also applies to differences between the Physical Model and the Subjective Model. Examples might be such as "large" and "red." ("It seemed large to me, even though I understand that its size is actually small (below normal size statistically)." "For some reason it seemed red to me, even though I understand that it was actually reflecting light primarily in the orange portion of the spectrum.")

And the difference in meaning, dependent upon the model, or context, may be easily understood by almost everyone.

But what is less obvious is that both models can use the same word, that means something different depending upon the model in which it is being used, but without recognition of that difference by many people. There are some words that many people use with little awareness that such use is basically incorrect because of lack of awareness that there is such a difference in meaning, such word usage sometimes essentially being metaphoric.

The best example of all, I believe, is that of "energy." People have very little awareness that "energy" as used in describing the experience of being "full of energy" or of "lacking in energy" is not the same as the "energy" that the physicist is referring to when describing the energy coming from the sun or the energy being converted from potential energy to heat energy, or being released in nuclear reactions. "Energy beverages" are ones that contain caffeine, not ones that necessarily contain more calories (which might make a person sluggish or sleepy, and therefore less "energetic").

A close look at the use of the word "life" will, I think, reveal the same common fallacy. "Life" to the biologist means something different than "life" as used by many religious practitioners and advocates of positions on abortion, as will be discussed later. But you may guess that the religious practitioner will tend to be using the Mental Model when using the term "life." Certainly one is using the Mental Model when one reports feeling "lifeless," or describes a person as "full of life."

For another example, when the biologist says that a species developed a particular characteristic "in order to" compete better with other species, he or she does not really mean that the species analyzed the situation and made a decision, but simply that the particular characteristic had the effect of allowing the species to survive longer and/or reproduce more efficiently and productively. So the phrase "in order to" is metaphoric, and suggests an implication that the evolutionary biologist would not agree with.

Such incorrect use of language by non-scientists is occasionally referred to as "pseudo-science," especially when the effort is to create the impression of scientifically acceptable statements for the purpose of making money, but it is really also a perfectly normal and accepted communicative behavior.