André A. Pais wrote:

REFLECTIONS ON SOLIPSISM

Solipsism is based on the idea that "only I exist" or "only this experience exists" or "only this exists." Some of these expressions are subtler than others, but all amount more or less to the same. It is true that nothing in experience directly affirms anything other than experience itself. What is overlooked is that nothing in experience actually denies anything "outside" experience either. Experience is totally mute, totally silent - it says nothing whatsoever about anything (be it internal or external to it). Even concepts are utterly silent, since, in a final sense, they don't point to anything either - they are mere sounds, vibrations, images, etc. In this sense, experience - and even conceptual processes - is totally incapable of refuting or establishing solipsism.

Solipsism is also based on a half-baked intuition of non-duality. The very concepts of "this" or "I" or "mine" depend on their opposites. So, by saying that "only this exists" I'm already establishing its opposite - some "that" that is nonexistent. "Existent-this" vs. "nonexistent-that" is a dualistic stance, making solipsism inherently self-refuting. Experience is devoid of "other" or "thatness," but it too is devoid of "me/mine" or "thisness." There is nothing exclusivistic in experience - there is no exclusion of anything. It's rather the opposite, experience is intrinsically open-ended, expansive and accommodating - even of concepts positing closed, constricted and excluding attitudes.

Also, solipsism seems to be based on notions of limited space and mutual exclusion of experiences. There is a sense of "there is only here" and so a "there" is excluded. Again this is dualistic, as without the notion of "there" there can't be a "here" either. So, in the non-conceptual spaciousness of experience there can be no sense of "here." So solipsism still embraces ideas of spatial extension, distance and separation, which it then paradoxically uses to refute notions of "other separate places," etc. So, we have dualistic principles being used in the defense of some non-dual solipsistic reality.

There is also the sense that experiences are mutually exclusive - if "this" experience is "here," "other" experiences cannot be simultaneously "here." Yet, we can cultivate an openness to the possibility that "everything is already here," that "everything is intrinsically included" right within this very experience. In the same way that we can develop our conventional senses (or other "senses") and experience things previously unnoticed - but that were already present -, we can also conceive of developing perception (or some kind of empirical sensitivity) in a way that allows the accommodation of an infinity of experiences, in opposition to the previously "singular solipsistic experience." That's what omniscience seems to entail - a non-conflicting appreciation of the totality of experiences, a full embrace of the entirety of the space-time display. In cutting through the solidity and seemingly exclusivistic nature of space and time - what is "here" is not "there," what is "now" cannot be "then" -, the "whole field" can become naturally manifest.

The sections of our experiential field that seem more obscure and concealing (like the sense of past and future experiences, and the notions of beyond the horizon and behind/bellow/above "me"), which are all instances of some type of impenetrable not-knowing, can be seen as representatives, clues or empirical "handles" that can serve as portals or doorways into the infinite dimensions of experience that remain unrevealed and unaccommodated. "Other times" and "other places," even in infinitely cosmic scales, can be seen as mere subtler dimensions - and yet unappreciated - of what is already here, of "this very experience."

Another angle of exploration is to consider if "this sole experience" is either one or many. A "many" can only be composed of a plurality of "ones" or units. Yet, no unit or singularity can ever be found - it's a logical and empirical impossibility. So, notions of singularity and plurality fall apart, and thus solipsism falls apart, since it is based on the idea of being the "singularly existing thing." Also, if "this experience" was the only existing thing, where would the seemingly diversity of experience come from? It either comes from something else (refuting solipsism) or it is generated "internally," in which case "this sole experience" is itself already a pluralistic experience.

Also, in the absence of a sense of there being some singular observer, experience is understood as "self-luminous" and "self-knowing"; why then can't the diversity of experience be already a case for so-called multiple perceivers or observers? Solipsism is based on the idea that "only I perceive" - but if all objects (material, mental or emotional) are already "self-knowing" and "naturally luminous," how can there be a sense of "only I perceive"? Experience is not intrinsically one for it arises as diversity; and it is not intrinsically many, since it's embraced by utter intimacy and non-separation. Solipsism, being based on solid notions of singularity and plurality, is incapable of appreciating the transparency and spaciousness of experience; and it is incapable of appreciating the fine balance of appearance-emptiness, a luminous display that is beyond materialistic, solidified and dualistic tendencies - that is, in fact, beyond all notions whatsoever, be they dual, non-dual, both or neither. Solipsism seems to be a classical example of an attempt to interpret an utterly transcendent and unlimited reality by making use of somewhat mystical and yet still conventional and limited notions and perspectives.