Kant said, and it still holds true today, that “it always remains a scandal of philosophy and universal human reason that the existence of things outside us… should have to be assumed merely on faith, and that if it occurs to anyone to doubt it, we should be unable to answer him with a satisfactory proof” (Kant, I., 1997. Critique of Pure Reason, Cambridge University Press, Bxxxix). It is from this scandal that my understanding of the concept of person begins.

There have been numerous attempts to refute Descartes’ argument that it is not possible to prove the existence of anything beyond the subjective self, not least by himself, but whether it was the logical positivism of AJ Ayer, Moore’s appeal to common sense, any of the numerous linguistic or religious assaults, or Kant’s own theory of synthetic a priori concepts, all have been unable to do the work that their authors wanted, or needed, them to.

These theories simply do not provide me with the right sort of knowledge. The kind that I want has been labelled unreasonable, but I believe that in this of all matters I am justified in demanding the strongest kind – that it is, after Descartes, inconceivable that I could be mistaken. If dreams and illusion of the senses are possible, if I have ever believed that I was in a physical state that, in relation to the world I usually call physical, was false, then I cannot be sure that anything other than me as a thinking being exists.

The knowledge that one cannot know that the world around one exists outside of one’s subjective experience of it is the catalyst for the concept of the person. I suggest that every subject, assuming that there are any other than me, possesses this knowledge unconsciously. The recognition of the chasm that exists between what we believe we know and what we do know underpins and pervades the subjective condition. It is the nascent form of what we call the human condition; it gives rise to solitude in a world full of subjects.

By way of contrast and to make my meaning clear, I am not concerned with the situation in which a subject comes to know that nothing exists beyond it, although how it could arrive at such knowledge is, at least, unclear. The effect of such knowledge would likely be a complete alteration of the subject. What I am referring to here is the knowledge merely that one cannot know that anything outside oneself exists, and a consequence altogether more subtle.

The profound metaphysical vertigo that is the result of this knowledge leads the subject to need to affirm the material existence both of itself and, by extension, everything it perceives, but it cannot do so through an appeal to something that it perceives to be in its self for it is this self that must be affirmed. The subject searches its experience then for something concrete, a hook on which to hang the world.

It is understandable that the subject looks to beings that it perceives as similar to it. For example, I perceive myself first as existing and second as existing as a human being, so to admit the existence of other human beings that I perceive is both easy and helps to render my own existence as a human being firmer. But I have no knowledge of another human being’s existence as a subject, so I must create the idea. I ‘put something into’ the apparent human being that my experience does not prove is there.

This ‘something’ is personhood, a fully subjective concept extrapolated from my experience as a subject. It has to be subjective, because it has to erect a bridge where none is. By attributing personhood to the human beings of my experience, I am able to tentatively leave my subjectivity and traverse the chasm between me and the material world, because the concept contains existence as a necessity.

Once human beings exist, I can begin to extend the concept of personhood – and therefore existence – to any being that I perceive to exhibit what to me, based on my subjective experience, suggests a subject. Although I may not call them people, I am ready to recognise elements of that concept in them, and if I were to experience any such being exhibiting all the required facets, I would be ready to employ it to describe it.

Once I have granted existence to subjects, it is just a short step to allowing it of material objects, especially as I experience subjects as bound by the material themselves. As I can no more know that something is a subject than I can that anything material exists, to admit the existence of subjects is to do the same for anything that I perceive; I have leapt the chasm. What begins as the concept of personhood expands to bring the entire material world into existence.

The expanded concept is similar to Kant’s description of space and time as a priori synthetic concepts, which I like to think of as a framework that the subject lays over its experience. However, he mistakenly believed that material objects were necessary for a subject to orient itself within this structure because he failed to truly accept the wholly subjective nature of the concepts. What cannot be learned directly is necessarily subjective, and the subject needs nothing outside of itself in order to know where it stands in relation to something that is of itself.

This theory could be criticised for requiring the unconscious mechanism, which raises questions about the singularity of the subject or self, and I am not prepared to admit the possibility of self deception. However, it is not necessary for the definition of self to stipulate that it must be aware of all its activity. It is feasible that the unconscious is simply a mechanism, but even if the self were to include within it a sub-self it would still be no less a part of that self, however unpalatable one might find that idea.

It is also open to the charge, as has been recognised, that it demands an unreasonably strong form of knowledge. However, even if it were assumed that the material world does exist, I cannot find personhood in it. It is not a quality that can be possessed, but, I maintain, a certain kind of subjectivity that is bestowed on something by me.

A third criticism is that the subject is said to admit the existence of other subjects before it does the material, but within the experience of a subject there is more evidence for the latter than the former. It must be remembered, however, that a subject’s experience is wholly subjective, and I know what it’s like to exist as a subject before all else.

Therefore, the concept of personhood is nothing more than the attempt by the isolated subject to end its solitude. In order to mitigate the anxiety that results from existing in a world that lacks empirical foundation I extrapolate from my own experience and endow my perceptions with a firmity that they simply do not warrant outside of my desire for it.