It becomes a question as to whether or not visual proofs are reliable. Optical Illusions show that Visual Proofs are the least reliable of all proofs. Modern people have other ways of knowing, other than the visual or even the sensual. There are specific measurements for various parameters and science is helpful in this regard as it pertains to objective knowledge. However, where subjective knowledge is concerned, neither scientific measurement nor sensate experience is of much benefit for knowing. Subjectively, no other person can see what I see, if my sight is a reference to some Abstract Conception. Abstract Conceptions are not known by sense perception. Neither do Abstract Conceptions exist in a causal relation to objects subject to sense perception . Moreover, "believe" refers to FIDEISM. Fideisms do not typically suffice for knowledge. The common criteria for modern people, which does suffice for knowedge is reason, or in other words, logic. Deductive Logic in specific, always shows what is true, providing that the Premises are true. .