We actually live in hyperspace: our universe really has four spacial dimensions. However, our bodies are fully four dimensional; we are not wafer thin slices a la flatland. We don't perceive there to be four dimensions because our visual cortexes have a defect somewhat like that of people who can't notice anything on the right side of their visual field.

Not only do we have an absolute denial macro, but it is a programmable absolute denial macro and there are things much like computer viruses which use it and spread through human population. That is, if you modulated your voice in a certain way at someone, it would cause them (and you) to acquire a brand new self deception, and start transmitting it to others.

Some of the people you believe are dead are actually alive, but no matter how hard they try to get other people to notice them, their actions are immediately forgotten and any changes caused by those actions are rationalized away.

There are transparent contradictions inherent in all current mathematical systems for reasoning about real numbers, but no human mathematician/physicist can notice them because they rely heavily on visuospacial reasoning to construct real analysis proofs.