In reference to a type of philosophical system that argues for solipsism but at the same time dualism, there hasn’t been any substantial work towards such a claim or argument, we haven’t seen any philosophers who argue even for the existence of solipsism itself, other than pointing out its unfalsifiability, which is never a good argument for anything. It’s entirely possible to make such a claim even though there’s no reason to believe in solipsism when the alternative makes more sense, in other words, there is no good reason to believe in solipsism other than its unfalsifiability.

Where solipsism posits the notion of there not existing independent consciousnesses outside of the consciousness which is aware of its own existence while simultaneously contains the belief in the idea of solipsism, a philosophical dualistic argues for this consciousness to be of immaterial origin, to be of a different “substance” than the material world. It is possible to hold the belief that I am living in a solipsistic universe, and that what I believe to be “me”, my awareness, or whatever description of consciousness I choose to adhere to, is located within this framework, yet made of a substance, or has an essence, that is different than the matter that makes up the material world. This itself is logical from its own perspective, but like many things that make sense within its own purview, it could be at odds with concrete reality. The fact that this consciousness is integrally related to the material realm is something that modern man cannot deny, as related neural damage and its affects to consciousness has been long proven in neuroscience, and the relation between certain contents of consciousness and our brains structure has been mapped, broadly speaking. But whether the essence of this materially caused consciousness is itself a material or non-material substance, doesn’t truly matter to me. Any experience shows that being conscious has a feeling that points us to the belief that it isn’t a material thing, it is something different, but this is merely perspectival. I believe this conscious essence is part of the phenomenal world just as much as any other phenomena, but from the subjective experience it feels as if it is separate. Whether this counts as philosophical dualism or not is not important to me, the truth is, and this picture of a materially arisen subjective experience of “myself” which is unique to humans, enabling emotions, hierarchical reasoning, and mental time travel (as Joseph LeDoux described as our ability to put ourselves in hypothetical future situations), all arising from a concrete material structure, is to me a borne out scientific fact.

In the spirit of still entertaining the question, we can take as a hypothetical a solipstic universe yet viewed from an Advaita Vedanta nondualist approach, rather than a philosophically dualist approach. This entails that our consciousness is the only one in existence (solipsism), yet posits that the content of this consciousness – labeled object – and the consciousness which it is aware of – labeled subject – are one and the same in their essence. Our “self” in this context has blurred the lines between the subject and object, the arising of a phenomenon in consciousness becomes who we are, as it is our experience, it is more than what we see, but what we are experiencing, and this, in this line of reasoning, is me. Thus other people, being objects to our subject, become us, or we become them, as parts of the whole totality, that merely is. Thus the material realm and the non-material realm, are able to be “seen” yet “excepted” cognitively as being one and the same.

When entering into a non-dual frame of mind, we no longer make the conscious recognition as subject and object, neither appears in awareness, all that (if done right) appears in awareness is the experience of the present, yet not conceptualized as I am seeing, I see a car, rather, just the experience of “seeing” is what makes up the consciousnesses momentary awareness (this of course is impermanent and constantly changing, just like all other phenomena). This approach is merely a mode of our being, a mode of non-duality, which has, in effect, tricked the brain into separating the distinction between object and subject, and fused the conceptual understanding, as well as experiential understanding, into conceptualizing both aspects of the world as one and the same.

Most of us don’t adhere to solipsism, yet we can easily recognize its infallibility, and we also, generally, don’t spend much time in a non-dual mode of being unless we are a dedicated yogi. While this is generally our state of affairs, we can see the benefit and apparent truthfulness behind the conceptualization of ourselves as part of a whole, as part of a totality of phenomena manifesting themselves within the universe. We, as people, and experience, as consciousness, is an aspect of the universe itself manifesting itself, and in our tiny book of this universe, we are the universe becoming aware of itself. At the same time, we intuit our experience as appearing radically different from the material realm, yet directly caused by it, and arising from it. This contradiction naturally needs rectifying, and it is done so by the realization that what we intuit isn’t necessarily the case in reality, no matter how much we would like it to be. The material world necessarily is the world we find ourselves in, it is what we are perceptibly entwined with, it just doesn’t appear that way, from our perspective. This is, in effect, objective non-dualism, yet simultaneously recognizing infallibility of solipsism as well as the subjective notion of philosophical dualism.

On a correlated note is a theory I have been expounding, off and on, for years now. It appears to be unfalsifiable in the same way solipsism is – that of “Differential 4th dimension”. If we take the proposition that all beings lie in different 3 dimensional space within the present, what happens when we carry the conclusion to the 4th dimension? Meaning, it would be unfalsifiable to suppose that all conscious beings could lie in a different time dimension, as our x, y, and z dimensions differ, why is it we assume our T dimension is the same? As to what is my present, right now, given a deterministic universe, where the only true arrow of time is represented by the equation of entropy, it is, in effect, a different time dimension than what any other consciousness is located within. My present could be your past or your future, but we can never truly know which moment in time someone else’s consciousness is currently located in, when looked at from our subjective perspective. This theory is solipsistic in reference to the present, but it admits the existence of other consciousnesses, but staying true to the absurdity of the world we currently find ourselves in. This world where we are unable to grasp the content of other people’s consciousness (apart from inference in reference to our own), nor the existence of other consciousnesses in other beings, apart from appearances. But due to the similarities displayed in the outward projections of our own consciousness, and that of other beings, we can conclude, due to the unlikelihood of the antithesis, that other beings appear to have consciousness in the present, yet we remain uncertain as to whether our present moment is the same location, in time, as their present moment.