The only reality is perception. Facts are negotiable; perception is not.

Since this is the case, I believe that the only knowledge we can gain through our senses is that of our own consciousness. However, if science is done properly, I believe that we can gain additional knowledge from this. Of course, we need to acknowledge the fact that we might be living in Plato’s cave and that science is being done with this backdrop. Should this be the case, then the only knowledge we would have would be that of our own consciousness.