Nihilism

[Angrboda]

I think I can go either way on metaphysical nihilism, presuming I understand it correctly from your brief description. I can whole-heartedly embrace metaphysical anti-realism in that the fact that we have experience (the act of perceiving something, whether it be things, an emotion, a pain in the head, or a feeling of unreality or disconnectedness -- any experience), this fact alone doesn't demonstrate what the cause of that experience is. We seem hard wired to "feel" that the world is real in the same way we're hard wired to desire food when the body needs nourishment, sleep when we are tired, and to see things that aren't there (e.g. the whirling snakes optical illusion where we perceive motion where none exists). We analogize our own existence based on what we perceive about the world, namely that effects have causes. Hume's analysis of cause and effect needs to be applied here in that cause and effect do not exist in the world of our experience -- we see one thing immediately followed by another, repeatedly, and we infer a causal connection between the two -- a connection that is wholly created out of what Hume terms the imagination (we might prefer to call it conceptual understanding). We never see any "linking rod" between the cause and its effect, only the strength of the correlation between the two [1].

As Hume notes, we sense bitter or sour, salty, sweet, color and so on, but material substance is not a sensation; we infer material substance from sensation, but it is not itself a sensation. Observation by its nature entails interacting with substance using matter or energy, and noting the changes to that matter and energy (e.g. light bouncing off an object), and inferring what happened between the input of matter or energy and the output; but what lies between is unknowable. We accept Descartes argument, "I think, therefore I am" on account of our experience of the world consisting of effects requiring causes, therefore the effect of thought requiring a cause, that thought requires an existent. But what if our experience, the very fabric of our world is entirely fictitious -- what if there is no world to base an analogy on? What then becomes of the argument by analogy from existence? I don't know. And while my gut instincts are screaming that unless something in some sense "is" then there can be no/thing to have an experience; but then, again, that gut feeling is just another furry sensation, an experience which could very well be based on a lie. I'd like to believe the analogy is sound, that there is sense to experience and that "facts of experience" at least loosely correspond to "facts of the world", but wanting and having are two different things. To quote the show House, M.D., "Only two things you ignore. Things that aren't important, and things you wish weren't important. And wishing never works.”

To make my point more concrete, I'd like to introduce my own variant on the "brain in a vat" idea that I like to call the 2D brain in a vat. Presume that instead of three spatial dimensions there are only two. But even so, the 2D world gives birth to 2D life, and 2D life in turn yields 2D intelligence complete with 2D technology. One day the scientists in 2D world pose an interesting question. "What," they wonder, "is it like to live in 3 dimensions instead of 2." Having perfected their 2D brain science, they decide to answer the question using a simulated life form. They create a "brain in a vat" in their 2D world, who lives, thinks and experiences a simulated world in three dimensions, even though in reality there are only 2 dimensions to be had. This "3D brain in a 2D vat" experiences all the things we do -- its world has height, depth and width, things have solidity, pieces can be combined and then taken apart again -- anything you or I experience, they can too. Now most of us consider the existence of three spatial dimensions beyond reproach. But how do you know that you aren't a 3D brain in a 2D vat?

[1] There is a famous paper in 20th century philosophy by Edmund Gettier which questions whether knowledge is "justified true belief" (See: ). According to which, a person can have a belief that is both justified and true, but still not possess knowledge (the belief is only coincidentally true, and the justification inadequate given the true). One answer to the quandary is to propose that there must be a causal link between the truth of the thing, and our justification of belief -- that the two can't be mere accident. Unfortunately, how to give legs to the idea of "causally connected" is hard enough under normal conceptions of causality -- if we retreat to Humean skepticism on this point, the battle is certainly lost.