I have an argument outline for rejecting hard-skepticism, though I'm not quite sure if it fully works and I was wondering if it's actually interesting, or just rubbish.
Firstly, I'll lay out the 3 forms of hard-skepticism I'm aware of:
- Descartes’ Malevolent Demon - No external world exists, but my perception of one is the result of a malevolent demon who has built a fully formed illusion of one.
- Brain in a Vat - None of my perceptions correspond to the way the world is, but rather are the results of a scientist who has my brain in a vat and triggers all of the proper neurons to provide the illusion of my world.
- Nick Bostrom’s Simulation Hypothesis - “At least one of the following propositions is true
(i) The fraction of human-level civilizations that reach a posthuman stage (that is, one capable of running high-fidelity ancestor simulations) is very close to zero.
(ii) The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero.
(iii) The fraction of all people with our kind of experiences that are living in a simulation is very close to one."
Therefore, it’s possible, if not likely, that we are living in a simulation.
So, let us assume Skepticism and say that our perceptions do not correspond to present reality. If this is the case, then according to all of the skeptics, our false perceptions have to come from somewhere (an external source). If we take Manipulator A to be the one providing the illusion of reality (i.e. the mad scientist in the brain in a vat, or the human-like species running simulations), then Manipulator A should also have the exact same argument to question her reality. (I should point out that Manipulator A does not need to be a conscious being. In fact, she could simply be my body. The only requirement for her is that she lies external to “I”.) That is, there’s no reason for “I” to be the only one skeptical that “I”’s perceptions are real. Even if Manipulator A does not question, there’s no reason for the arguments to not apply to Manipulator A (Similar to how the arguments of skepticism apply to animals even if they don't have the capacity to be skeptical). In fact, the arguments flow upstream to any creature capable of manipulating. Then, in turn, Manipulator B would be the one providing the illusion to Manipulator A. However, Manipulator B should also question her reality and so on…
However, at a certain point we know that somebody along the chain is actually experiencing reality as it stands (otherwise, nobody would experience anything real and we would enter an infinite regress of illusion. So, because we know that there is something real and that this real thing is what allows for all representation, it must be that at least somebody is experiencing it). So, let’s take this person to be Manipulator Z. But, Manipulator Z is bound in conceivability to that which she experiences. So, the only illusions that she can provide to Manipulator Y are permutations of actual things (that is, take reality to be the unordered set of all things that exist, then the illusion can be comprised only of some subset of that set). In turn Manipulator Y’s illusion must be a permutation of her reality...and so on. Until we get to “I” who experiences an illusion that is based on the reality of Manipulator A which still all comes from actual reality. This leads us to the rather strong conclusion that we cannot experience anything that lies outside the realm of reality. That is, if we are experiencing it, it must be some part of reality.
Does this work? Thanks in advance!