In popular science the moon illusion is often described as a "2000 year old mystery" yet to be adequately solved. It is also often repeated that science is superior to our senses and everyday understanding (see B.Greene The fabric of the cosmos). the message here is that we should preferably turn to science to understand the world.
The moon illusion is the observation that the moon appears larger on the horizon than it does at the zenith and a large amount of academic research has tried to explain the basis of the illusion.
Absolutely incredibly all of this research appears to rest on a geometrical fallacy.
Ask anyone" "Is the moon closer on the horizon than overhead" what is you answer? A simple geometrical diagram shows that it is further away on the horizon than it is overhead (about 7000 km). More to the point the light from the moon when overhead travels through about 80 km of atmosphere but when it is on the horizon it travels through about 1100 km of atmosphere.
It is a simple matter to explain the illusion form these facts (scattering of light).
Check out the moon-illusion images on google to verify that at the highest level of scientific research the above error is present.