
Ouroboros (by way of Wikipedia)
The Ouroboros is an ancient, universal, mythological symbol found in virtually all cultures. Among other things, it symbolizes cycles and progressions, like the repeating changes of the seasons.
It also applies to politics and religion, and symbolizes the downward spiral created by ideologies. A person or group enters an ideological spiral and moves around the circle until it bites his, her, or its own tail. This is why extremes, when viewed from a distance, often resemble one another — Fascist states resemble Communist states, white supremacists behave like jihadists, and so on.

Yeats was a true mystic. He saw the spirals and gazed into the eyes of Ouroboros. Unfortunately he was, to some extent, stuck in a spiral of his own…
This downward spiral is like a black hole from which no light escapes. It is constriction, compression, insularity. Cut off from the greater world, trapped in the internal logic of an ideology, people and groups cease all attempts to see things as they are and begin to see things as the ideology says they are.
This is all understood very well by mystics. We see that lye, although it is of extremely high pH, burns the skin just the same as acid which is of extremely low pH. Freezing draws out moisture just as well as baking, dry ice burns like a hot iron, and Antarctica is as inhospitable as the Sahara.
But there is an upward spiral also. It is an opening, loosening, widening gyre and its extremes also resemble one another. This is why when physicists speak they sound like mystics, and why science looks like magic. As we let go of restriction and open up to possibilities, amazing things are allowed to happen. Great realizations and unique insights are experienced and dreams are realized.
The whole universe understands this as only a living thing of infinite size can truly know. It is the grand Ouroboros, the cosmological snake biting its tail. It compresses, restricts, squeezes itself into a single point with infinite mass, then explodes into a Big Bang. When the energy of the explosion is spent, and the universe has expanded to its maximum size and thinness, it halts for an instant before beginning its slow contraction. An endless cycle, ever repeating.
To be human is to be a fragment of the divine. While we cannot, at least not at this stage of our development, alter the universal, cosmological cycle and halt the expansion of the universe, we can control the cycles of our minds. Possessed of free will, we can pick whichever spiral we choose.
Will you choose an opening gyre rather than a tightening one? Or will you contract and grow ever smaller, denser, and restricted until no light can escape from your eyes?