I want to consider another difference between non-dualistic forms of spirituality and those that see this world as not sufficient in itself and ourselves as incomplete. (Note that in a logically consistent non-dual system this world is perfect when perceived correctly and we are perfect now if only we knew it. That is why enlightenment is potentially open to anyone at any time in such systems). Previous posts have gone into this difference but approached the question from the perspective of individuality which is effectively discarded in non-duality, a fundamental misconception in my view even if based on something real which is the shifting of the centre of identity. However, here I wish to look at the matter from another angle.
There is nothing beyond. There is nothing beyond this world and there is nothing beyond ourselves. Earth is heaven when seen with the eye of vision. We see as God sees when we know ourselves to be pure consciousness. Now, I do not doubt that Earth can appear heavenly in vision or ecstasy or any kind of peak experience but this is not the same as saying it is heaven. The mind is its own place and in itself can make a heaven of hell and a hell of heaven, as the poet has it. But still this world is not heaven. There is something much more real behind it, something of which this world is only a dim reflection even if that reflection can partake of the divine in certain modes of awareness. But if non-duality means what it says it does, and if the implications of its claims are understood, then there is no possibility of attaining to a higher state of consciousness than is attainable here and now. The very idea of qualitative difference is meaningless. There may be worlds beyond this one but for a true non-dualist these cannot offer anything more.
Is that not a dispiriting thought? There are not greater and greater vistas of glory. There cannot be if everything is here and now. There is not something more and better than this world or, even if there is, that does not mean our participation, our joy, in it can be any greater. Non-duality means nothing is better, nothing is higher, nothing is more. It is ultimately a sad and sorry philosophy which negates the beauty of life.
Of course, most people who subscribe to this philosophy don't think like this but that's because they have not fully thought through the implication of their belief system. It's all very well, as far as it goes, if you take it simply to mean that the world is not fundamentally separate from us. But when you really think it through, you find that, so keen is it to avoid any kind of separation, it destroys any kind of difference. It may deny this and say that created things are real on their own level but as it effectively regards that level as one of ignorance, this is not much use.
Far better to return to the traditional Western idea of God and creation, both of which are fully real. Non-duality takes the trinity of spirit, soul and body and reduces it to spirit alone but a more comprehensive and inclusive understanding sees them as all having a role to play in the totality of what we (and the universe) are, even if there is a hierarchical ordering to this group. But the fact of hierarchy does not negate the lower levels of the order, all of which combine to make something greater than just the highest on its own. The interaction of spirit and matter produces something more than spirit alone, both for God who can share his life with other free beings, and for us who can enter more and more deeply into the endless mysteries of existence.