As a Zen practitioner, aloneness is something that I have recognised as a result of many years of meditation practice. The truth is that we are alone - always - yet we are together in that alone-ness. We cannot live in the mind of another, so everything we know about others, is created in our own minds.
As I continued meditating and contemplating this through the years, I have realised that alone-ness and loneliness are two different things. The difference is desire.
If we desire to be understood and needed by another and it is not forthcoming, then we will feel lonely. but if we drop this desire then we can be full of "self presence" and realise that we are part of the whole universe and that nature itself cares for us. To realise this though, we need to accept and realise that we are more than just a physical body. That we are an energy (or spirit) inside a physical body and mind. We came into the world alone.. We go out of the world alone.. In between we worry about being alone sometimes, but really we don't need to.
We were OK when we entered the world, so who is to say that we are not OK when we leave the world?
From a discussion I have particpated in.. For other points of view click here.