I know nothing, because nothing can be absolutely known.
However, I believe I know, and that is sufficent.
I exist, because it can never be otherwise. Any debate on this is worse than impossible, it is foolish.
Other exists -- that which is beyond my control:
Since I cannot control everything I percieve, there exists something outside my control that I in some way percieve. Every person or object I meet is part of this other. Whether this other is truly made of many or "all is one", I cannot say. Whether this other is in fact a part of me and dependent upon me for its reality, I also cannot say. At times my own body and brain may become other. My thoughts will flow without the consent of my will -- else christianity would have been the final resting place of my debates. I have worked my body as I willed, but one day it fell to the ground and refused to get up, knowing its needs better than mine. Since then I have respected its rules about rest and sustenance more carefully.
Other has a definite reality. (truth)
The world of the matrix is simply not worth my time. I may enjoy such speculation in fiction, but in truth I never doubt this world's existance. In fact, the matrix itself would have physical existance, so it is irrelevant.
Physical law is sufficient.
There is nothing in this world, whether myself or other that is not sufficiently explained by the laws of physics or chemistry. Such that there is no need nor reason to assume anything beyond these explanations.
Specifically: There is no spiritual reality
Since everything, even emotion and conciousness can be explained as permutations on natural law, and natural law is an infinite state unto itself, there is nothing beyond physical reality or inherent in physical reality that relates to the concepts of souls, spirits, demons, love or conciousness.
There is no morality
Morality is a combination of innate, instictive behaviors and learned reactions. Good is that which we are taught is good, bad is that which has undesireable, or potentially undesireable consequences. Evil in others is anything that hurts us.
I reject as inconsistant all insistance that there is no physical reality, because such arguments take place within reality. I reject all insistance on spiritual reality, because no such events have ever taken place within the spiritual realm.