The “brain in a jar” is a thought experiment of a disembodied human brain living in a jar of sustenance. The thought experiment explores human conceptions of reality, mind, and consciousness. This article will explore a metaphysical argument against artificial intelligence on the grounds that a disembodied artificial intelligence, or a “brain” without a body, is incompatible with the nature of intelligence.[1]

The brain in a jar is a different inquiry than traditional questions about artificial intelligence. The brain in a jar asks whether thinking requires a thinker. The possibility of artificial intelligence primarily revolves around what is necessary to make a computer (or a computer program) intelligent. In this view, artificial intelligence is possible if we can understand intelligence and figure out how to program it into a computer.

The 17th-century French philosopher René Descartes deserves much blame for the brain in a jar. Descartes was combating materialism, which explains the world, and everything in it, as entirely made up of matter.[2] Descartes separated the mind and body to create a neutral space to discuss nonmaterial substances like consciousness, the soul, and even God. This philosophy of the mind was named cartesian dualism.[3]

Dualism argues that the body and mind are not one thing but separate and opposite things made of different matter that inexplicitly interact.[4] Descartes’s methodology to doubt everything, even his own body, in favor of his thoughts, to find something “indubitable,” which he could least doubt, to learn something about knowledge is doubtful. The result is an exhausted epistemological pursuit of understanding what we can know by manipulating metaphysics and what there is. This kind of solipsistic thinking is unwarranted but was not a personality disorder in the 17th century.[5]

Descartes AI