… consists of the signifier and the signified. The signifier is the sound/image/word, the form. The signified is the concept. Take “dog”: the word itself is the signifier, the idea that the word represents is the signified. Together these parts make up the sign. An actual dog– a real dog– is the sign’s referent, its material correlative in time and space. (For a good introduction to the sign– and, more generally, semiotics– go to David Chandler’s webpage, Semiotics for Beginners.)
One of the things Baudrillard argues in “Simulacra and Simulations” is that the sign has been de-linked from its referent. That we live in a hyper-mediated environment in which we are 24-7 inundated with signs (images, sounds, language) lacking context. A whirlpool of signification which is so ubiquitous and overwhelming that we are effectively deprived of referents, the material realities which signs are supposed to stand in for. This results in a vast confusion, a hyperreal world of appearances produced by the “precession of the simulacra.”
Very roughly speaking, this situation mirrors Plato’s famous Cave Allegory from The Republic:
We have to adapt Plato’s words to our own purposes because in formulating the allegory of the cave he was above all concerned with proving the ultimate reality of the forms (εἶδοἰ)– an effort which we can categorize as idealist. In fact, for Plato the physical world has the character of a copy, so it’s easy to see how his ideas are, in a sense, directly opposed to the scenario described in The Matrix and Neuromancer.