"What they refer to as the habitX = any verb ending in ing e.g swimming
Y = a certain group of dreaming by the Aborigines, is not what the Aborigines themselves believe them to bepeople e."g Martians
"What everyone refers to as the habit of X(ing) by the Y, is not what the Y themselves believe them to be."
"Them" is referring to dreamsX. Is theIf I use of 'them' in the second part of the sentence, will it be grammatically correct since "habit of dreaming"X" seems singular to me.
"They" is "Westerners"
Note: The quote in the original version of the question had What Europeans . . . rather than What they . . .