Imagine splitting Christianity in two. One half gets the divinity of God, His omnipotence, the natural hierarchy of Creation, and the harshness of His law. The other gets the humanity of Jesus, the orderly nature of Creation, equality before the eyes of God, and the gentleness of Jesus’s teachings.
Thus separated, these aspects would be distorted and taken to their logical extremes, untempered by their complements in the other half. Divinity without humanity leads to fanaticism, humanity without divinity to secularism. Omnipotence without order becomes divine caprice, order without omnipotence gives rise to scientific materialism. Unrestrained hierarchy encourages oppression, equality implies egalitarianism. Harshness leads to cruelty, intemperate gentleness to degeneracy and lawlessness. These complements start to resemble Islam and modernity, respectively.
The comparison can be extended further. God told His people to be fruitful and multiply, Jesus never had children. The extreme left wants to sacrifice their own kind to heal the world, Muslim extremists want to sacrifice everyone but their own kind. Paradoxically, though, jihadism encourages self-sacrifice while leftists seem reluctant to make personal sacrifices. I have a hard time dismissing this polarity as mere coincidence.
With this in mind, it seems curious how intent the West is on importing its spiritual complement. Is it on some level motivated by a hope for reconciliation or synthesis? I doubt the feeling is mutual.
I got to thinking along these lines when I noticed an interesting synchronicity: the filioque first appeared in the 6th century and Muhammad was born in 571. That was probably a coincidence.