Philosophers have been known to sometimes conjure up world-views which seem dazzlingly at odds with our everyday take on the world. Among the more, if not most drastic ‘-isms’ to be found in the history of philosophy, then, is the standpoint of solipsism, derived from the Latin words ‘solus’ (alone) and ‘ipse’ (self). What is that supposed to mean? It adopts a position that only acknowledges the existence of one's very own mind and opposes that there is anything beyond the realm of my mind that could be known. What a drastic contradiction to the way we normally view the world, indeed. Allow me to emphasize some implications that would arise were one really to take the solipsist view for granted. The aim is to briefly adumbrate how a solipsist view would cut us off from the social world and from the existential dimension of our own death.

A basic argument from a solipsist's point of view – let's call our imagined solipsist Sol – is that I can by no means achieve an ‘objective’ view of the world: it is always inevitably connected to, even generated by my perceptions, my reflections, my abstractions etc. Certainly, this represents an important point when discussing the question: ‘What can we know?’ I cannot perceive something without someone – me – perceiving it. And yet most of us would consider it bizarre and absurd to think of myself as the giant ego that produced and sustained the world in my mind.

There are several objections to solipsism, like the impossibility to perceive all the different perspectives of the world we experience at once: we are always situated in a concrete position from where we perceive the world, and there are other perspectives we can take, but only one we currently can have. Another objection is that the world is not equipped according to my own wishes and preferences: why would Sol, the solipsist, fill the world with all those unpleasant things he dislikes, when he were to be the only truly existing individual, the one at the very helm?

Surely, Sol, the solipsist, would not maintain that there were no world at all, or nothing at all. In fact, saying that ‘nothing is’ already is something in itself. And the world is there for the solipsist as well – it is only that it is rooted in the presence of one solitary mind.

There is, however, a thought experiment we can make, which yields a puzzling result: It concerns death from our everyday point of view on the one hand, and from the perspective of Sol, the solipsist on the other, and it goes like this: We only die once, or do so presumably – no-one who is alive can ever know what it is like to be dead. All our guesses, all our hypotheses are those of somebody who is alive and sufficiently well to ponder on what it might be like to be dead. From the viewpoint of natural science, it can be said that the matter I consist of will dissolve into different states of matter and energy. But the internal perspective, the dissolving of one's own psyche cannot be imagined, because as long we are imagining something, it is always there, as has been stressed by psychologists and philosophers before.

Now, what about Sol, the solipsist, and his death? Surely all of us conclude that since everyone else has to die, and we become witnesses of the deaths of relatives, friends, partners … and we grieve – we have to die as well, and do not seriously doubt this rational knowledge. The analogy behind this runs basically: Every human being has to die; I become witness to the deaths of other human beings – since I am also a human being, one day, I will have to die too. That is, we infer the inescapability of death for ourselves because we consider the outlines of our own existence basically comparable to the existence of other human beings. They die, we die. Quite clear, quite likely, although we cannot know this with paramount certainty. But one would most probably furrow one's brow to hear somebody utter: ‘What? I will die too? Me? I thought it was only all of you that had to die.’ There are no exceptions, be this a good or a bad thing.

Sol, the solipsist, cannot resort to this analogy, were he to take his position seriously. Instead, other human beings would not be like him at all: he would have to consider them productions of his mind, mental phenomena only, and not more; certainly not independent, individual existences. And the mental phenomena in question may have the outward semblance of independently existing human individuals, but they cannot be the same from this standpoint. Sol, the solipsist, is on his own. He is the only experiencing soul, the only actual individual. And when he becomes a witness of a human being dying, this only signifies a drastic change in the appearance of some mental phenomenon, but not a real, independently existing human being. And therefore, he cannot extrapolate from this change of appearance (a living phenomenon becomes a corpse – a lifeless, unmoving apparition) to the assumption that he will have to die as well. Sol, the solipsist, is left to an uncertain future. The phenomena he calls ‘human beings’ appear to be lifeless at one point, and he may call them ‘dead’, but Sol is immortal in that he has no way of coming to the conclusion that he will suffer the same fate. He has no sure indication of his experienced world ever ceasing, since there is no precedence as to what happens with solipsists in a solipsist's world. And since he is the all-experiencing being, what should his mind turn into if he did die after all? Philosophy and sciences have shown often enough that something cannot simply turn into an absolute nothingness. Many open questions … Sol would have a hard time in defending his world-view when seriously queried.

I suppose hardly anybody would wholeheartedly agree with this conclusion of an immortal solipsist. It would be deemed unrealistic and highly whimsical. In fact, the extreme standpoint of solipsism has few followers (if any at all) amongst contemporary scientists. If we dilute the kernel of solipsism quite a bit, though, it serves to remind us that even though there are hard realities such as death which we all will have to confront, each of us perceives the world from his or her very own perspective, and that all knowing, perceiving and thinking, all human mental activity is and has to be related to the respective subject, the experience of a human being. There is no world-view without a viewer of the world. This has been emphasized in recent times by another of those ‘-isms’, constructivism.

And yet, Sol, the solipsist's case represents a strident exaggeration – his world, although certainly still some form of world, would, after all, be an ultimately lonely, isolated one, with no real company, no counterpart proper. The thought of a possible immortality would be a cold comfort.