The Reality of Consciousness

You hold a baseball in your hand. You see and feel the baseball in your hand. You are quite certain that the ball is real, and yet, you cannot be absolutely certain because the ball might be an hallucination. If so, then the ball cannot be real. Yet, whether the ball should be real or an illusion, you can be certain that you possess the sensations of seeing and feeling the ball. Physical objects can be real or illusory, but in either case, one's sensations of those objects must be real.

You have an operation on your brain. The doctors rig a mirror so that you can stay awake and observe the operation. You observe your own brain, but it is just a physical object like a baseball which may be real or an illusion. Yet, whether it is real or an illusion, you can be certain that you are having the sensations of observing your brain, real or illusory. 

Something must be producing these sensations. The only possible answer is that your consciousness must be producing these sensations. Furthermore, this consciousness must be outside of your brain because the sensations of your mind has to be real even though your brain may be an illusion. Thus, an argument can be made that the only existence of which one can be absolutely certain that it is real is a consciousness separate from the brain. 

If your brain were an illusion, it certainly could not be producing the sensations of it that you see. In other words, should your vision of your brain during your operation be an hallucination, you cannot be certain that your real physical brain is producing the hallucination since it also may be nothing but an illusion. The point is that it is always the physical that can be an illusion; never the subjective because something produces the undeniable sensations whether they are illusory or real, and that something has to be subjective.

One may object that their physical brain produces their sensations, but one can never be certain that one's physical brain is real because it, like any other physical object, could be an illusion. But one conclusion has to be absolutely certain, and that is that while an illusion itself will be unreal, the undeniable sensations of it must register on something because the sensations themselves can only be unavoidable, actual experiences. This something which registers undeniable sensations can only be a consciousness separate from brain activity.