1. Since the phenomena of The Matrix, the possibility of a machine simulating the world we know and all our sensory experience is a fun and popular concept to consider. While we take it lightly, it does present a problem when we seriously consider, how can we know this is the actual world we are experiencing? The classic theory of knowledge, withholding the objections made against it, requires justified, true belief. The problem falls into the camp of justification, more specifically, are we justified in believing that what our perceptions tell us (as a general rule) is a representation of truth? The modest foundationalist would say so; after all, as much as we may try to doubt our sensory experience, we all live according to what our senses tell us. It is ingrained in our nature. Our perceptions, they would argue, count as strong inductive evidence for the world being as our senses would tell us. However, if indeed the fact was that our senses were controlled by a machine, we could not know, for even the extremely strict basic belief structure of the classical foundationalist (logical truths and internal mental states) cannot bring us to this conclusion. Therefore, we have no way truly to justify “knowing” such a fact as our world is created by a machine, as opposed to the contrary. We can establish no case for it in either deduction or induction. We can only conceive of the possibility. Then, we must wonder, does it matter? It may, if for example the more specific situation, if known in full, would enlighten you towards a better way of living (perhaps to escape the machine’s control), but since we cannot not come to this knowledge by ordinary or known means, it matters little in a practical sense. Only once we establish some form of justification for the claim can it matter.
2. Descartes makes the claim that we can always be certain about our mental states, and I must agree with him. I can easily see how one can doubt the cause of his mental states, or what reality is it that affects his mental states. Perhaps the computer I’m looking at is a delusion, and I’m actually a crazed, schizophrenic who types away for hours in the back of his padded room on a rock. However, though the computer I perceive may not be a computer as I believe it to be, it cannot be denied that I perceive a computer in the forefront of my mentality. What Descartes refers to is not an external but an internal state of affairs, and thus, by a principle of definition, must be inherently true. If I feel pain, whatever I may believe about the cause of that pain, the fact that I feel pain is impossible to deny. This is arguably the very definition of pain, that specific feeling which I perceive. It is barred from public observance to be sure (strictly speaking), but the fact that I have this mental state I cannot deny. If I am feeling pain, how can I doubt that I am feeling pain? This is similar to Descartes’ famous, “I think therefore I am.” He cannot doubt that he doubts. It would seem absurd to declare such.
3. Yes, I believe we can know the external world exists beyond a reasonable doubt. Of course, this depends upon one’s definition of “beyond a reasonable doubt.” I am not prepared to say it is beyond doubt, but beyond reasonable doubt implies that given everything we may know, it is extremely unlikely. Most skeptical possibilities about the deception of our senses in fact rely upon something going on external to our mental states. Descartes had an evil and powerful demon deceiving us; others have contemplated the possibilities of our brains being in vats or Matrix-like worlds. However, in all these examples, though we may be completely incorrect about the nature of the external world, the external world still exists. In order for us to doubt an external world, we must then be forced to believe that our minds deceive us, giving us a vivid image of the external world we believe we experience.
While it is technically conceivable that my mind deceives me, I find it extremely unlikely. I think the most compelling reason for this is that in order for there to be no external world, my mind must not be contingent, but necessary. Though my memory may be deceived as well, there is nothing inherent to the nature of my mind that it must necessarily exist, either coming into being ex nihilo, or having existed by itself forever. To assume nothing external assumes no cause, and searching internally, I find no reason that my mind has a necessary nature in line with that which we only assume God has. If my mind was some necessary being, I could not further understand why my mind would deceive itself on so many accounts, from my perception to my memory to the nature of its own being. I doubt very much so if it is possible for my mind to hide from itself the nature of its own being. If we believe so, the mind (and therefore existence) would be a strange place outside the bounds of logic my own mind has so restricted itself to. While there is still room to doubt the external world, I find it more difficult than many may think.