Consensual Hallucination
"Consensual hallucination" is how William Gibson, in his novel Neuromancer, describes the cyberspace. I have always thought that this is an interesting imaginery to work with. The idea something exists only due to our capacity to make it real by collectively believing in it. The same idea appears in Jacque Derrida's concept of signature. The French philosopher said that it's only through the eyes of the others that a signture (a name!) becomes potent. This is very Lacanian if we stop to thinkg about it.