[TimTheTinker]

I like the structure and insight of the argument, but I think it needs some re-working.

Definition 1 could be broadened to: "Loneliness is when we aren't known and loved by others."

Loneliness can occur because we're socially isolated for some reason. It can also occur when we're with others who don't know us, because we're not willing or able to open up to them. This could be because we are afraid to be real with others, but it could also be because we're afraid to be real with ourselves.

There's nothing like being real with yourself, being real with others, being loved by others who really know you, and knowing/loving them as well.

Incidentally, this ties in with Christianity's value proposition: no human can both know and love you perfectly, but God can and will to those who receive his gospel.

[l-]

One can be known and loved by others, but lonely, marooned & castaway on an island. Alone by definition is just "all one" - no others, which is not #1. One would be better off consulting a dictionary before going on a definition tangent.