It is partly perception in that we feel differently because of it than we would feel if there was no human there. To capture this feeling, perhaps you can imagine a robot that looked fairly realistic but that you knew was just a robot. Perhaps it would even move fairly realistically, but you still knew that it was made only of plastic and metal. The experience would be substantially different than if you knew it was an "actual person."

But this is also a belief. If for instance you simply could not tell by looking at it which it was, your belief as to which it was would determine whether you would have this experience of "being in the presence of" a person. So this feeling is something that goes along with a specific belief.

So what I am focusing on is that feeling, which is indistinguishable under most circumstances from a perception. You see not just a body, but a "person." You "feel" that person's "presence."

That feeling includes rather hard-to-describe components such as that the person has an awareness, in turn, of you. And that feeling that that person is really present and aware of you is enormously increased by the experience of "eye contact."

The origin of this feeling may be in part the neurological capability of having it (for instance, the presence in the brain of a particular neuronal arrangement), but also in part what has been acquired very, very early in life, when the infant begins to have that basic recognition of "the other," probably most often "Mother," with whom the infant makes eye contact.

This ability to experience the other "person," and to have this intense subjective experience when making eye contact, is considered to be an extremely important capability, and when it is absent, an individual is considered to be quite impaired.

Now it is this experience of "the other" that I want to focus on.

There is a whole world of modeling that occurs around this basic subjective experience. This modeling is both within the Subjective Model and within the Objective Model. So let's look at this modeling.

Within the Subjective Model, there is the development of beliefs about the state of this "other." We "sense" (feel and believe) that the other is feeling certain things or has certain intentions. It is certainly true that the "mind" (what we are of course talking about) of the other person is believed to be in a particular state because of the movement of the eyebrows and eyelids, the muscles around the mouth and forehead, the position of the body, etc., but what we "sense" is not each of those things separately but a certain state that we react to as a single "entity." We react to the other's "state of mind," not to his or her eyebrows. We are of course talking in part about the experiencing of "empathy." It is essentially the opposite of "dehumanization." The belief that the other person has a "mind" has been referred to as "theory of mind," but we are also talking about what feels like a direct experiencing of that mind when in the presence of that person, not just the effort to imagine what the other person is experiencing and to label it with words.

Now I am going to suggest that this "sensing of the other" is such a fundamental and vital part of subjective experience that it plays a major role in our lives and in our cultures, and is a factor in beliefs that actually have a major impact, both positive and negative, on our quality of life and our decision-making.

I believe that you will probably agree that this fundamental "experiencing" of the other's "presence" is probably a major component of the source of our beliefs about the concept of "spirit."

We sense that the other person has a "spirit." We believe that the other person has a "spirit" that is not completely identified with the body of that person. When a person dies in our presence, we tend to lose that feeling, that "perception," of his or her "spirit" or "presence." We are confronted with a "corpse," that is missing its "spirit." But it is not unusual to maintain the feeling that the "spirit" still persists, but with a less apparent location.

Obviously, there is a close connection between the meaning of "spirit" and that of "consciousness." But the meaning is not identical. We might "experience" the anesthetized person as "unconscious," but we would still "experience" that person differently than we would if we suddenly realized that he or she had just died.

Now this experience of the "spirit" of the other person is actually not always confined to the experiencing of humans. Pet owners will assure you that they sense the "spirit" of their pets (though they may not use that terminology). Sometimes this "sensing" is the "experience" of mutual understanding. "My cat understands me. We communicate." And this sort of reported subjective experience is referring to more than some conditioning of the animal to our commands and some "conclusion" that the pet owner is arriving at about what the pet must be "thinking."

Many pet owners will easily report that the attachment to their pets is equivalent to their attachment to humans, and the death of a pet can elicit the same amount of grieving that would occur in response to the death of a significant other human.

So some would say that of course their pet has a "spirit." And over the history of our species, I believe that it has been frequent that we have attributed "spirits" to other species. We probably do this a little less than we did a few thousand years ago, but we might question whether perhaps this phenomenon is fairly normal and natural, and whether perhaps there are things about how we have come to be as a part of "civilization" that have caused us to have less of this feeling about other species. Nevertheless, I believe that most of us will recognize a feeling of "presence" on the part of at least some other species.

If we are approached by a tiger, we sense that there is a "being" that is looking at us. And we also sense that this is perhaps a stronger spirit than that of other less ferocious species, and perhaps a stronger spirit than our own. So the "sensing" of the spirit may include a "sensing" of the "strength" of that spirit.

(Some people who have developed positive relationships with such animals sense that those animals love them. And when they are engaging in affectionate interaction with them, those people certainly are not feeling what they would be feeling if they were interacting with automatons.)

So it is not surprising that "primitive" people have related to other species not only on a somewhat equalitarian basis, that is, on the basis of one spirit to another, but also even in a deferential and respectful manner. And an extension of this phenomenon is the preferential and respectful treatment of certain non-human species within certain societies.

Now it is not that much of a leap for someone to feel that he or she is in the presence of a spirit that is not associated with a currently perceived body. When we are in the room with someone, we "sense" his or her presence. In fact, that may happen even though the person has, unknown to us, left the room. And, especially when a loved one has died, we sometimes experience the presence of that person's "spirit." Some of us carry on conversations, even if one-way, with loved ones who have died. This may happen especially upon visiting a cemetery.

So it is not surprising that our species has come to have beliefs about and subjectively experience "spirits" that are completely without any accompanying primary physical entity, and thus can't be seen. In fact, it is not at all surprising that we have developed the concept of ghosts, gods, goddesses, devils, and demons, both human and animal.

Children are known to believe that inanimate things may be alive and aware of them, a phenomenon called "animism." They have to unlearn such things as they grow older. So perhaps it is natural to have the feeling that parts of the non-animal world are aware of us and have intentions toward us, with our perhaps only fairly recently giving up such ideas, at least as adults. And even adults may be said to be experiencing the "spirits" of inanimate things, as, for instance, when some of us angrily throw a tool that seems to refuse to cooperate with our efforts to use it successfully.

And many of us have religious orientations that foster the "awareness" of "all existence," animate and inanimate, being permeated with something that is "alive," a world in which we are only temporarily walled off into our own personal subjective experience, awaiting the time when we will once again merge with "the universe," becoming "one with all that is."

So what I have been discussing is what I believe all of us can recognize as the concept of "spirituality." Spirituality is the "experiencing" of there being "consciousness," or something similar to it, in at least some of those things that are a part of our subjective experience that we do not consider to be part of the "self."

What I have been presenting is what I believe we can see as a normal and natural part of the Subjective Model, subjective experience and beliefs about that experience. When spirituality, as here described, is totally absent, serious disorder is present.

On the other hand, we know that there is mental illness in which a person has this experience far beyond what is normal, and is considered to be delusional. There are people who, as a part of their mental illness, "experience" the "presence" of (often malignant) entities that are watching them, and perhaps even putting thoughts in their minds or taking thoughts out of their minds. It is probably true that we are much more prone to think about "delusions" than we were a few thousand years ago, when we probably took the word of those reporting such experiences. And we can ask why we are more prone now to think about the possibility that such phenomena are examples of "delusional ideation," as opposed to the acceptance of such phenomena as manifestations of spirits (good and evil). Let us explore that issue.

What we have been talking about is only subjective experience and the Subjective Model. But what we have developed to such an enormous extent only fairly recently is the Objective Model, with its epitome, the sciences.

We have seen that the Objective Model is an effort to model "Reality" (that which exists independently of our perceiving it or thinking about it) with accurate beliefs, such that accurate predictions can be utilized in decision-making, and it is based upon the effort to learn the basic rules of the universe. Although the Mental Model (a model within the Objective Model) does indeed deal with subjective experience, it is really, as we have seen, a shorthand approach to understanding most accurately whatever it is in the brain that is associated with reports of the experiencing of entities of subjective experience (thoughts, feelings, perceptions, etc.). From the standpoint of the Objective Model, mental entities are models of whatever occurs in the brain when such entities are manifest in subjective experience.

So if we are going to attempt to model spirituality within the Objective Model, we must realize that we can only be talking about whatever is going on in the brain when the individual has the subjective experience of the "presence" of the other, or the "spirit" of the other, whether we make reference to that brain or not.

To clarify this further, let us again use our thought experiment described earlier. With our imagined advanced technology, let us assume that we are able to recreate the exact state of the brain in an individual shortly after the brain has been in that state. So we have the individual interact with the other person such that he or she will have that subjective experience of the "presence" or "spirit" of the other person, and then shortly afterward either remove the other person and reduplicate the state of the individual's brain or keep the other person there but anesthetize or kill the brain of the individual. Under which circumstance would the experiencing of the "presence" or "spirit" of the other person be reproduced? Where is that "spirit," then? Is it not in the individual's brain? Of course, as has been discussed, we know that that subjective experience is dependent upon the brain. So the entity that is being modeled in the Objective Model is a particular network of activated neurons in the individual's brain, not something that exists "in" the body of the other person, even though that is the way it seems, that is, is modeled within the Subjective Model.

So what this means is that something that is very important and perhaps essential to the mental health and quality of life of the individual is something that is a part of the Subjective Model, but not the Objective Model. Spirituality can be studied in the Objective Model by studying the brain, but it can be lived only within the Subjective Model. Science will not deal with spirituality or spirits other than to study the phenomena as activities of the brain that is "experiencing" them, but that does not have anything to do with the value (positive or negative) of the having of the subjective experiences of spirituality.

Science will indeed be able to study the correlation of reports of the kind and degree of spirituality on the reported quality of life of the individual and on the likelihood of living well physically and mentally.

So my opinion, already stated and implied, is that spirituality is quite important. But also, it is completely personal, in that it obviously can vary, as has been described, from one person to another. There is no appropriateness or feasibility of "requiring" others to have a particular spirituality.