When people have a fever they perceive themselves to be cold. They feel cold. Their perception is that they are freezing. Are they freezing in reality? No. Are they really cold? No...they are burning up with fever. Their perception of an actual physical condition is incorrect. Is there a perfectly plausible reason they perceive themselves to be cold? Yes, because their body is so hot that everything around them feels colder. The air itself feels cold upon their skin so they perceive themselves as being cold. Fact is though, they are not. Much like one may perceive that the sun is moving around the Earth, because from the perspective of one not knowing any better, upon looking up, that is how it appears as the track of the Sun makes it's way across the sky, however...the fact remains that this perception is wrong when compared with reality. Much like the feverish person who is "freezing".