“I know this sounds like metaphysical megalomania of an unusually shameless kind. Merely being [Thomas Nagel] isn’t good enough for me: I have to think of myself as the world soul in humble disguise. In mitigation I can plead only that the same thought is available to any of you. You are all subjects of the centerless Universe and mere human or Martian identity should seem to you arbitrary.”

-Thomas Nagel

The threads of ontology, philosophy of mind, and personal identity are inextricably woven together; by which I mean, our view of one of these automatically makes presumptions about or informs our view of the others. The problem of personal identity over time, for instance, arises from linguistic conventions that presuppose a certain (hidden) view of substance and mind. What follows is an analysis of implicit ontological assumptions (not necessarily justified) that arise when discussing personal identity, and how these assumptions must be modified in light of a non-dualistic solution to the mind-body problem.

Let’s begin with a discussion of solipsism (the idea that my experience is the only experience that’s real), as it perfectly exemplifies the way in which these various views all inform each other. A statement is made asserting the non-existence of viewpoints (ontology) other than my own (identity). On the one hand, it seems absurd to deny that others do not experience anything. You are mugged; an event which does not benefit you, but benefits others – doesn’t this provide good evidence that others have motives and experience desires? You’re stabbed, you cry out, and you feel pain – doesn’t this provide good evidence that when I’m stabbed, and cry out, I probably feel pain too? On the other hand, solipsism is widely considered to be irrefutable. Why? Because solipsism represents the ultimate skeptical viewpoint: that can only be said to exist which is directly experienced – and the only way for me to directly experience the existence of your perspective would be to BE you, which would entail the forgetting of all the experiences that constitute my identity. If I were you, I would once again be in the same position, but from the opposite perspective.

Thus, we might conclude that solipsism is useless precisely because of its irrefutability: what we would expect to see if it were the case and what we would expect to see if it were not are identical. But in making this conclusion, we’ve gotten ahead of ourselves; allowing ourselves to be carried away by the logical manipulation of ill-defined words. For instance, what does it really mean for me to deny that your viewpoint exists? What constitutes the existence of a viewpoint? A passage by Douglas Harding, in his essay On Having No Head, points out a discrepancy that might help illuminate the problem:

“The truth is that the verb to see has two quite opposite meanings. When we observe a couple conversing, we say they see each other, though their faces remain intact and some feet apart, but when I see you your face is all, mine nothing.”

In other words, there are two ways in which we interchangeably use the same phrase, “to see:” one of them is first-person and the other is third-person. When we see two people looking at each other, we use the phrase “they see each other” in a different way than we use the term “I see them.” Their seeing of each other is an assumption that we may be correctly said to make based on certain given facts: neither of them is blind, they are both in close range of each other, their faces are pointed towards each other, and their eyes are open. But these all apply to the behavior of objects in our visual field – we may be seeing them see each other, but we are not seeing their sight of each other.

And this is what it means to have a perspective – to use perceptual verbs in the first-person sense. If I were really seeing them seeing each other, then I would experience three visual fields simultaneously: one of me looking at them, and one for each of them looking at each other.

A similar outlook is expressed by the philosopher Ludwig Wittgenstein, ever mindful of the precision of language use, in The Blue Book:

“Sometimes the most satisfying expression of our solipsism seems to be this: ‘when anything is seen (really seen) it is always I who see it’… Now let us ask ourselves what sort of identity of personality it is we are referring to when we say ‘when anything is seen, it is always I who see.’ What is it I want all these cases of seeing to have in common? …When I think about it a little longer I see that what I wished to say was: ‘Always when anything is seen, something is seen’. I.e., that of which I said it continued during all the experiences of seeing was not any particular entity ‘I’, but the experience of seeing itself.”

Solipsism denies this sort of experience to other people, but the interesting part is that, unraveling the subtleties of language, we see that solipsism and the traditional view of personal identity (i.e. that we are all each separate people, with experiences of the world forever divided from one another) amount to the same thing; that is, the denial of the existence of sight (as I know and experience it) from certain perspectives. For instance, if I stand side-by-side with a friend in the hallway of my house, I should expect not only that I, identified in my thoughts as Jeff, am seeing the hallway from angle X, but that my friend, identified with his own name in his thoughts, is seeing (actually seeing, in the first-person sense) the hallway from angle Y – but if our identities are fundamentally different, and my experience is forever closed off from his, then that is simply not the case. Even if we were both hooked up to brain and body scanners, ensuring me that nearly identical neurological processes were occurring in each of us, my perception of the hallway from angle X is what would actually be occurring in first-person, whereas his, differing only by a slight degree of angle and self-concept, would not ever occur.

It is tempting to say that he would experience a first-person view, but that it would simply not ever be available to me, as my experience is in my mind, and his is in his mind, privately available only to him. But this is where the non-dualist solution to the mind-body problem comes in: if we deny Descartes’ res cogitans, or mind-stuff, then the inner-stage on which such other perceptions could occur is eradicated. There simply is no inside of my mind as opposed to outside in the world; there are only neurological processes naturally occurring in the physical world, which has no inside or outside.

We might, then, be led to say “but the physiological process of sight is occurring in two different places, in two different brains. Your first-person experience is the physiological process occurring in this brain, which is different from that one.” True. But if seeing is supposed to be happening in both places at once, then why is this (the hallway, as well as the machine’s readouts, from angle X) what is being seen as opposed to that (the same, from angle Y) at the given time?

If, then, we take the traditional view of personal identity (so often wrongly seen as the opposite of solipsism), then the set of experiences actually had, in all of eternity, will be limited to my own; those identified with J.H., born on May 12, 1989, dying at some undetermined point in the future. At that point, belief in the existence of other perspectives is like belief in God – faith-based and unfalsifiable. It is not solipsism which is useless because of its irrefutability; it is the belief in other minds.

So what does a denial of solipsism really amount to? What does it mean to attribute the existence of the first-person viewpoint to other people? It would essentially mean that all experience can be said to occur from a generic first-person viewpoint which has, at some times and places, certain memories, and at other times and places has different memories. So, when I am standing next to my friend in the hallway, both perspectives are experienced in the first person sense, but the viewings are not co-conscious (just as my current view of writing this on the computer is not co-conscious with an experience of myself in, say, middle school), and each experience includes different memories. The division between people falls to mere social convention. Oddly enough, we find that this is already somewhat the case within our own, normally-conceived every day lives. Not all of my memories are available to me at any given instant, and I am certainly separated from my past self and past instances of first-person seeing by vast amounts of time and space.

All of our knowledge of the world is structured on our experience; networked through language, each individual ego attempts to gain an idea of the others and define its relationship to the whole. But we can’t suppose that there is really, substantially more there than the subject describing itself. Using the best methods it could to attain objectivity, humanity searched for the truth and found only itself looking.

The concept of the generic first-“person” subject of experience we have arrived at is very reminiscent of Parmenides’ One in The Way of Truth: always present, without beginning or end, as what exists. But, just like in The Way of Opinion, or appearance, false divisions arise; the illusion of separateness, variety, coming and going.