Is It All A Dream? Eternal World Skeptics and Two Responses

May 12, 2023

In browsing the vast internet you may have come across a dialogue along the lines of “We live in a simulation.” While most of us brush off these commenters as conspiracy theorists, it might surprise you to know this sort of external world skepticism is common in philosophy. External world skeptics believe we can't know (or justifiably believe) any contingent truths about the external world. This belief rejects the idea that you know you are looking at a computer right now, or even that I know the chair I sit in actually exists. (It's important to note some external world skeptics believe that reality is a sham, while others merely deem it a legitimate possibility). External world skepticism does not object to necessary truths, (ie. they would not deny that 1 + 1 = 2) but they firmly deny the justifiable existence of any contingent “truths.” So, on what basis do these skeptics reject reality, and should we consider them more than a silly idea?

Have you ever thought you were awake when you were actually dreaming? Or had a layered dream, where you are still asleep when you “wake up?” These sorts of experiences are the basis for the external world skepticism “dream argument.” When we truly wake up from these layered dreams Leonardo DiCaprio’s absence lets us know we aren’t in Inception, but the external world skeptic questions how why we are so certain we are not still dreaming. Perhaps this reality is merely another layer of fabricated fiction in which we have true sensory experiences. Is this a legitimate argument? Think about it for a moment. We will cover one more (the most common) external world skeptic theory before considering the possible faults with each of their arguments.

The Brain in a Vat argument (BIV) is the most famous of the external world skeptic arguments. Let us imagine some hyper-intelligent scientists of the future have mastered technology to such a degree that they are keeping a brain floating in a vat of liquid, covered in electrodes and wires. With careful and targeted electrical signals they have programmed the artificial simulation we call reality. This is certainly a possible (albeit far-fetched) scenario. You may have come to realize that philosophers do not care much if something is infinitely improbable. As long as it could exist in the universe it's fair game. You may imagine the scientists having a nice laugh at us as they watch us saying “That’s ludicrous, I'm not a brain in a tub of liquid.” This is very similar to the dream argument, but it more easily allows us to understand why if we are in a dream, why it doesn't feel like one. Like the dream scenario, the BIV argument is very difficult to dispute, as the external world skeptic can brush off any evidence you cite as part of the BIV simulation. These theories, however, while seemingly valid, are not without criticism

The first (and a bit unsatisfying) response to the external world skeptic lies in the definition of what we say is known. Imagine you are a college student moving out of the dorm (as I was yesterday). Your mother calls and asks, “Is the room empty?” You are fully moved out so you reassure her that it is, and you haven't forgotten anything. You understood that by “empty” your mother was only referring to your belongings, not the provided desk or cobweb in the corner, and especially not the air molecules in the room. Certainly, she isn’t asking if the room is a vacuum. The external world skeptic is someone who would respond to their mother “No the room is not empty” because there is still matter in it. Importantly, the skeptic isn't just misunderstanding the word empty, they are misunderstanding what it is to know something is empty. They think to know something is true we must rule out every other possible alternative, but to know something in the common use of the word is only to rule out relative alternatives. When your mother asks if the room is empty the room being void of all matter is decidedly not a relative alternative. We can then reject the external world skeptic, saying that, while we may not know reality is a simulation in the sense that it is not a possibility, we can know that a simulation is not a relative alternative to our existence, and is exceedingly unlikely.

The second, simpler, and better response to the external world skeptic is that their arguments are infallible. Science and logic are defined by their ability (and goal) to disprove themselves. A theory must not only be able to justify why it is true but, be able to refute evidence of why it is not true or accept that it has been disproven. Theories are made to be challenged and adjusted. Any argument that seeks only to prove itself, and is conveniently incapable of being disproven is simply a bad argument. This is the case with the eternal world skeptic. It is a little different from astrology and some parts of psychology. A claim that cannot be proven false (while not definitively false) must not be taken as truth either.

So are the conspiracy theorists right? No. But, that doesn't mean they are necessarily wrong.