Solipsism is the view that I am the only entity to whom it is justifiable to ascribe existence. This is based on the fact that this entire world, as it appears to me, is in truth only a representation in my consciousness, and hence only exists in me. If I refer to observation for justification, I find that the critical condition for any observation is my consciousness and nobody else’s; I have never observed through anybody else’s. as such, I must always infer that other humans are aware as I am, but never have any direct experiential evidence for this. The argument goes somewhat like this:
I am a human and I am aware,
X is a human;
X must also be aware.
This assumes that being aware is a property of humans, just as speech, for example, is a property of humans. A solipsist would hold that this assumption is groundless. (S)He would assert that while speech is, in fact, a phenomenon exhibited by humans that have been observed by us, awareness, or consciousness, is not. The only consciousness we have ever been experientially confronted with is our own, i.e. my own. So, I am not justified in assuming that others are conscious. Now this debate is a metaphysical one in truth, since its primary concern is existence, and as such, requires metaphysical considerations. The War of Metaphysics currently raging in my mind has many conflicting militias, but generally, the divide is as follows. Realism vs. Idealism: realism is the view that the world exists absolutely and independently of any conscious being; Idealism is the view that the world is conditioned by, and hence contingent upon, conscious beings. Solipsism is perhaps the purest idealistic doctrine since it reduces the entire universe to a subject/object relationship, and in particular, one in which there is only one subject, namely, me. Realism is clearly an enemy of solipsism for if the world truly did exist absolutely and independently of consciousness, this would imply that consciousness is merely an emergent phenomenon supervening on physical states, in other words, that it is a function of brains, and hence that any entity possessing a brain would necessarily also possess consciousness. A more moderated, or perhaps adulterated, idealistic doctrine states that although the universe exists as object for a subject, there can be a plurality of subjects and this accounts for the consciousness of others. What if this view was actually the great reconciler of that tortuous war, bringing the warring factions together under its one banner, uniting enemies who suddenly recognize themselves in each other’s countenances? If we postulate that the world is a co-simulation in which all conscious minds are participants as well as creators, by virtue of simulating the world in order to perceive it, and hence to know it, it follows that these minds must be related to one another on a very fundamental level. By this I mean that they are connected by virtue of their being just parts of an underlying, or all-encompassing, mind. That this is so is due to the fact that, on the level of appearances, there is no sharp divide between any two objects and nothing can be sectioned off as individual and existing in its own right, which implies that the only truly existing entity is nothing less that the entire universe itself and as a whole, corresponding to which exists a whole mind, which nevertheless differentiates into, or appears in this world as, a plurality of minds.
This metaphysical framework that is beginning to be formulated in my mind seems like the perfect reconciliation between a materialist conception of consciousness and an idealist conception of reality. For me, metaphysical materialism is untenable due to the very simple refutation proposed by Schopenhauer which states that there can be no object without a subject for whom the object appears. This truth is self-evident and can be further demonstrated by the traditional epistemological question: if a tree falls and no consciousness is around to hear it, does it make a sound? In fact, we could extend this question to metaphysics and ask: if a tree falls and no consciousness is around to perceive it, does it exist? Well, in my mind there is no doubt that this demonstrates the impossibility of the existence of this tree precisely because of the fact that it has not been witnessed or perceived at all. Such a tree is, in fact, inconceivable and if anyone were to try to conceive of such a tree, there would immediately be a contradiction in that the very act of conceiving this tree requires a consciousness. In other words, in attempting to imagine this hypothetical tree, we find ourselves attempting the impossible since to even imagine it at all requires our awareness, i.e. our knowledge. So, nothing can exist without a knowing being who is the subject for whom this thing is object. This demonstrates that the reality of this world, this empirical physical world, is conditioned by knowledge and can only arise in knowledge and appears under the forms of knowledge, namely, space, time and causality. On the other hand, the materialist conception of consciousness is that which attributes all of our cognitive faculties to the function of our brains. This theory is very hard to disprove, especially since there is so much evidence for it, from the impact of psychoactive substances on the mind to the increasingly reliable work of the cognitive scientists in attributing function to structure in the brain. It seems evident that the brain is the source of all knowledge and hence that consciousness is a result of brain states. If it is to be maintained, however, that this knowledge is itself what conditions external reality, it would not be too difficult to find corroboration for this even in modern empirical science which agrees that the perceived world is no more than a representation in the brain and which indeed any rational investigation into the matter will elucidate. Consider the act of watching a bird in flight; is the bird that you perceive actually out there in space or is it not just electrical impulses in your head representing the form of a bird in the form of external space? A common reply to this is that while the image of the bird may be in my head, it is only because an actual bird, actually flying outside me, reflected light into my brain. To this I might ask, when do we ever make contact with this actual bird which is outside of me and which is not composed of brain states? In fact, the answer is never. Anything we perceive or conceive – in short, anything we know – must by definition be a representation in our brain, and hence nothing but electrical activity therein. So, the reality of the external world is only a semi-reality since it is not absolute and cannot be said to exist without our representing brains. But the empirical reality of this external world is not to be done away with upon making this claim and this can be shown by virtue of the fact that our expectation that it should exist independently of us is a delusion brought about by the inferiority of our intellect with respect to our understanding, the former of which is the faculty of reasoning and the latter perceiving. Because of the extreme rapidity with which the understanding produces the world of perception, we are misled into believing that it is genuinely there, whether we look at it or not. What we do not realize is that the world only enters into appearance upon being observed, before which it can’t be said to have existed, at least not in the same sense. That there must be some other sense in which it exists, however, is so because of the fact that this world is a representation, and hence must be a representation of something. In other words, there must be some inner nature of the world which only upon being projected into representation adopts the forms of space, time, and causality. The implication of this is that this original inner nature of the world must be wholly outside of space and time, which are only brought about through the functioning of brains. But there seems to be a problem here: how can space and time be brought about by brains if brains themselves require space and time to exist? Well, perhaps it can be argued that brains do not actually require space and time. If we consider this very carefully, we find that our brains are not accessible to us from the inside in the same way that our bodies are. Brains can only enter into the representation as objects, but can never be observed as pure subjects since this constitutes a contradiction. The brain is the subject that is required for every observation, and hence whatever it observes will be object for it. Even in the case of removing the top of my skull and using mirrors to be able to see my own brain, I am still only observing it as an object and not as a subject. The most fundamental form of all knowledge is that of the subject/object dichotomy, or that of the unknown knower and the unknowing known. The knower can never be known and the known can never attain knowledge. This means that there is always a schism involved in any knowledge whatsoever which can never be bridged and which is essential to all knowledge. Even self-knowledge still requires this fundamental form which in this case consists of the brain, which is the knower, and the body, which is the known. So, the image of the brain, produced by invasive procedures, is the not the same thing as the brain-in-itself. This image is only the appearance of the brain into the forms of space and time, occasioned by the arising of the necessary and sufficient causes and conditions for this appearance. However, the true inner nature of the brain, the brain-in-itself, is not extended in space and operative in time under the imperative of the law of causality, but transcends these merely phenomenal forms. This transcending of space and time necessarily eliminates plurality and individuality and reduces the multifarious and variegated phenomena of the world to just ONE entity. So, the brain-in-itself is the same as the body-in-itself and, in fact, the same as the entire universe-in-itself, that is in its inner nature prior to being represented, or what is to be represented. This thing-in-itself is called will by Schopenhauer and I am currently of a disposition to agree with him since it is true that will is the common denominator of all life and since my apprehension of my own will is the only thing immediately known in my inner knowledge whereas everything else is only known indirectly through interaction with the spatiotemporal manifold. But Schopenhauer asserts that will is also the inner nature of every object in the universe, is in fact the inner nature of the entire universe, which leads to the attribution of will to the behaviour of even inanimate objects which is a view that I am slightly more reluctant to believe, but nevertheless has a certain elegance and simplicity to it which is undeniable.
To conclude, it seems I have drifted a little from my original aim which was to refute the view that I am the only conscious entity in the universe. This is demonstrated quite simply by analysing one implication of this which is that the empirically real world, to a solipsist, would exist as no more than a phantasm, a mere hallucination. However, with the realization that this world always conforms to the law of causality and that this, along with the forms of space and time, is a function of brains we cannot help the conclusion that any being with a normal brain must necessarily have consciousness, and hence knowledge, making that being a subject and producing a world of perception to be object for that subject. That there is a plurality of brains implies that there must be a plurality of worlds, but these worlds must necessarily overlap and can be shown to be symmetrical with respect to the points of view of each knowing being. And so, the basis of all these worlds must be identical and is what Schopenhauer would call the will, identical and undivided in essence.