Cyberspace. A consensual hallucination experienced daily by billions of legitimate operators in every nation by children being taught mathematical concepts.
It is not materialism that is the chief curse of the world as pastors teach but idealism. Men get into trouble by taking their visions and hallucinations too seriously.
All observers not laboring under hallucinations of the senses are agreed or can be made to agree about facts of sensible experience through evidence toward which the intellect is merely passive and over which the individual will and character have no control.