Yet, the two concepts are often confused because they are both mediated by and reside on computers. The computer is a self-contained (though not closed) Universe. It incorporates the hardware, the data and the instructions for the manipulation of the data (software). It is, therefore, by definition, a virtual reality. It is versatile and can correlate its reality with the world outside. But it can also refrain from doing so. This is the ominous "what if" in artificial intelligence (AI). What if a computer were to refuse to correlate its internal (virtual) reality with the reality of its makers? What if it were to impose its own reality on us and make it the privileged one? In the visually tantalizing movie, "The Matrix", a breed of AI computers takes over the world. It harvests human embryos in laboratories called "fields". It then feeds them through grim looking tubes and keeps them immersed in gelatinous liquid in cocoons. This new "machine species" derives its energy needs from the electricity produced by the billions of human bodies thus preserved. A sophisticated, all-pervasive, computer program called "The Matrix" generates a "world" inhabited by the consciousness of the unfortunate human batteries. Ensconced in their shells, they see themselves walking, talking, working and making love. This is a tangible and olfactory phantasm masterfully created by the Matrix. Its computing power is mind boggling. It generates the minutest details and reams of data in a spectacularly successful effort to maintain the illusion. A group of human miscreants succeeds to learn the secret of the Matrix. They form an underground and live aboard a ship, loosely communicating with a halcyon city called "Zion", the last bastion of resistance. In one of the scenes, Cypher, one of the rebels defects. Over a glass of (illusory) rubicund wine and (spectral) juicy steak, he poses the main dilemma of the movie. Is it better to live happily in a perfectly detailed delusion - or to survive unhappily but free of its hold? The Matrix controls the minds of all the humans in the world. It is a bridge between them, they inter-connected through it. It makes them share the same sights, smells and textures. They remember. They compete. They make decisions. The Matrix is sufficiently complex to allow for this apparent lack of determinism and ubiquity of free will. The root question is: is there any difference between making decisions and feeling certain of making them (not having made them)? If one is unaware of the existence of the Matrix, the answer is no. From the inside, as a part of the Matrix, making decisions and appearing to be making them are identical states. Only an outside observer - one who in possession of full information regarding both the Matrix and the humans - can tell the difference.