Autobiographical note: I like paradoxes. As a result, I like thought experiments. As long as the box is closed, Schrodinger’s cat is both alive and dead. The Ship of Theseus is neither the original nor a replica. Borel’s monkeys will, given infinite time, reproduce the works of Shakespeare. Both James T. Kirks are the original. Achilles will never catch the tortoise.
Today, I learned about the brain in a vat thought experiment. Unbeknownst to me, I already had a basic understanding of it based on my knowledge of Plato’s allegory of the cave and the Cartesian position that there is no way of knowing that one’s experiences are truly taking place and not the result of an “evil daemon” fooling the brain into thinking the experience is real.*
In the experiment, a brain is suspended in a life-sustaining liquid and hooked up to a computer, which feeds it electrical impulses identical to those it would receive if it were in a skull. The brain believes that it is in a head and that it is going about its day as it would any other day, while in reality, it is just a brain in a vat hooked up to a computer. And, because the brain is being fed experiences that fall within “normal” parameters, it is impossible for it to know that it is disembodied and that none of its experiences are real. Theoretically, since the brain cannot ascertain whether it is disembodied or not, a person has no way of knowing whether his beliefs, the things around him or his experiences are real.
Essentially, the brain in a vat thought experiment is compressed solipcism that raises the epistemological question of a priori and a posteriori knowledge (and to some extent whether either is enough to ascertain reality).**
Think The Matrix.***
*See Meditation VI, which starts on page 42.
**As a general rule, I’m a fan of epistemology. Metaphysics and its evil, evil stepchild, ontology, less so. Heidegger and I can hang; Aristotle nearly drove me over the edge as an undergrad.