That quote about "rival gangs of magicians" is from British mathematician and philosopher Alfred North Whitehead. The full quote is:
"The mentality of mankind and the language of mankind created each other. If we like to assume the rise of language as a given fact, then it is not going too far to say that the souls of men are the gift from language to mankind. The account of the sixth day should be written: 'He gave them speech, and they became souls.' Yet the origin of language is wrapped in mystery. Language, in its development and daily use, exemplifies the highest principles of criticism. It is relevant to note that the technical language of science, especially mathematical science, is now driving ordinary language into the background of our consciousness—a remarkable development of the last three centuries. Science began as an anti-Aristotelian movement. Its great note was the appeal to observation. Yet science has reacted back upon the very instrument of its advance, namely language. In this reaction it has won a notable victory. It is transforming the language of daily life. On the whole, the gain is greater than the loss, despite rival gangs of magicians who mutter incantations expressive of the diverse temperaments of their respective chiefs."
The border between the Real and the Unreal is not fixed, but just marks the last place where rival gangs of shamans fought each other to a standstill.