Brain In A Jar: The brain in a vat, or brain in a jar theory implies our consciousness could be taken out of our bodies and that we could experience reality through the neurological connections of our brains. This idea has been the centerpiece of many works of fiction and ‘thought experiments’, which have sought to better understand what constitutes reality. The brain in a vat theory presumes that the brain is the origin of all consciousness, that the brain operates on electrical impulses and that external stimuli can affect how the brain operates. The terrifying implications are that you may be nothing more than a brain in jar a without anyway to prove or disprove it.