i think we can create our own illusions without having to be influenced by another consciousness. we do that through dreams, hallucinations, psychological tricks like denial; those dont depend on there being any other consciousness.
but i think it would be more likely that we would create the illusion of being alone rather than creating the illusion of being in a world populated by other creatures and people.
Who knows how the subconscient really works? Maybe its a shy second conscioussness? =)