Actually, it was
Plato's
Republic that first put forth the
notion of an
illusory reality. Plato's "
cave" suggested that all
human life and
experience is a
projection of events occuring outside the
realm of our perception.
If you stop to think about it, you will realize that we humans, as all living creatures, are always several steps removed from reality... We only "see" objects because photons of light bounce off the objects around us. These photons travel at finite speed, and are thus temporally delayed when they reach our eyes. Our retinas convert a narrow spectra of that light into electrochemical impulses, which then travel the optic nerve to the visual cortex, where the image is finally "mapped" onto our brains to be perceived by our consciousness. Likewise, we only "hear" vibration which is transmitted through the air, rattling the tympanum of our ears, in turn shaking various tuned oscillators called cilia. Finally, the brain reassembles this abstraction of "sound" back into a rough simulacrum of what is happening around us.
Similar cases can be made for taste, touch, smell, et cetera - the simple truth is, we have no direct means of ascertaining the true nature of the "reality" in which we exist. All is processed, all is abstraction.