TL;DR: As a species, we used to need religion and other pleasant fictions in order to cope with the wild world that spawned us. Now that we Homo sapiens are the wildest threat on Earth, we need truth more than fiction. Religion was initially an adaptive invention of Homo sapiens. Eventually, religion became maladaptive, threatening our survival. We need to put aside dangerous religions, especially the monotheistic religion, since monotheism tends to breed violence.
We don’t know when, how, or why apes experienced a cognitive revolution and became sentient, conscious, so-called wise ape-people (Homo sapiens: “Wise man”). We do know that consciousness brought to the newly sentient Homo sapiens mental abilities which enabled the species to ultimately dominate the planet. Abstract ideas now became tools and weapons.
Contemplation of abstract ideas was a new tool unavailable to non-sentient species, but it came at a cost. Now the species could ponder death, not simply witness, grieve, and experience it. Now they could recognize violence, be impressed or disgusted by it, instead of just instinctively using it as another tool of survival. Now they could contemplate the meaninglessness of existence, and be crushed by it, or even driven insane by it. Unless, of course, they could find a way to cope with this unwelcome awakening.
Along with all the civilization-building tools sentience eventually brought, it also threatened the survival of the species by distracting or debilitating them. Being distracted or depressed or insane were dangerous vulnerabilities, especially before the wild world had been tamed. These distractions from the hard work of survival were extinction-level threats when the new species was few in number and faced the stark binary of evolution: survival or extinction.
Now uniquely vulnerable to despair and existential grief, our species coped by inventing beliefs and faith narratives free of connection to physical observation. Fiction was born: Look at the trees; they’ve always been here… someone must have planted a garden and put us in it! Fictional legends became beloved myths, which became religious “Truth”. The new ability to see philosophical facts about the world encouraged formation of the basic original religious narratives.
Monotheistic religions (Judaism, Christianity, Islam) injected a uniquely aggressive exclusivity (All those OTHERS are wrong; OURS is the right one) into their narratives. From Abraham to Moses, the creators of the Jewish nation/religion insisted that they were the exclusive source of Truth. The Old Testament was asserted to be the unique scriptural collection in which to find the “only true God,” Jehovah. From Christ to Paul, the creators of the Christian religion insisted that Jesus’ death was the culmination of Old Testament prophecy, ushering in a new doctrine of grace through faith in their exclusive Savior. There was only one way to their gated heavenly neighborhood, and that was letting Jesus Christ control your mind. From Muhammed to the Sunnis and the Shia, the creators of Islam insisted that their spin on Old and New Testaments was the fulfillment of prophecy, making Muslim doctrine the only pure faith.
The aggressive exclusivity of these various flavors of monotheism quickly escalated into coercion and physical violence. That addiction to violence resulted in species-wide, self-inflicted suffering. Over the past two thousand years during which their narratives obsessed and distracted Homo sapiens, monotheism turned religion– the ancient coping mechanism– into a global killer.
Moses in the Old Testament taught his followers to slaughter the Canaanites in order to seize their land; he claimed he received this command from God. The willingness of Israel to defend their land with violence and cruelty continues today. Islam modified Moses’ shtick to fit their conquering narrative and have been in an ideological war with Christianity since the 7th century CE. Their fundamentalists drive themselves suicidally insane with their prophetic mission, “Jihad,” and have perfected the supremely maladaptive tool of terrorism. Christians went from persecuted to persecutors when the dominant empire in their area embraced the new religion in order to control their power-drunk narrative. The history of the last thousand years in Europe and North America drips with the blood of those brutalized and exterminated in the name of their god.
The most popular and dangerous ideas on earth are cherished by the violent, aggressive monotheistic religions crippling so many powerful cultures. Homo sapiens is at risk from the maladaptive mental virus of religion.