Consider the following misconceptions that have occurred over the last two millennia:

Bloodletting
Originating over 2,000 years ago in ancient Egypt, it was thought that blood contained “humours” which needed to be kept in balance by removing excess blood from a patient to prevent or cure illness and disease. The practice spread to medieval Europe, where bloodletting became the standard treatment for various conditions, from plague and smallpox to epilepsy and gout. This procedure famously may have been the major cause of George Washington’s death in 1799 after he lost an estimated 40% of his blood.

Trial by ordeal/Trial by combat
In medieval Europe, in cases when there was no witness, such as treason, adultery, witchcraft, or heresy, evidence from an absolute, or divine, point of view was sought. In trial by ordeal, the accused was subjected to a painful and usually dangerous experience (such as walking across fire or red hot iron, or dipping one’s hand in boiling water, or consuming poison, etc.) on the premise that God would help the innocent by performing a miracle on his behalf. Similarly, in trial by combat, a designated “champion” acting on either party’s behalf, would fight, and the loser of the fight or the party represented by the losing champion was deemed guilty or liable. 

Witch Tests
One such trial by ordeal were tests for witchcraft. Witch swimming: the act of tying up and dunking one accused of witchcraft into a body of water. Sinking indicated innocence (yet unfortunate death) while floating indicated guilt. The practice appears as early as the 9th century in Western Europe until it is banned by King Henry III in 1219, then reappears in 16th century Europe and Scotland. King James VI was a proponent claiming the devil refused the benefit of baptism and that water, which is the element of baptism, will effectively spit them out and prevent them from sinking. For example, in 1710, the swimming test was used as evidence against a Hungarian woman named Dorko Boda, who was later beaten and burned at the stake as a witch.
Prayer test: witches were thought incapable of speaking scripture aloud, so accused sorcerers were made to recite selections from the Bible—usually the Lord’s Prayer—without making mistakes or omissions.
Touch test: victims of sorcery were thought to have a special reaction to physical contact with their evildoer.
Witch’s mark: suspects were stripped and publicly examined for signs of an unsightly blemish – mark of the devil.
Scratch test: possessed people supposedly found relief by scratching the person responsible with their fingernails until they drew blood.
[See here for more information]

Causes of the black plague
The black plague or “black death” was the most fatal pandemic recorded in human history, causing the death of 75–200 million people in Eurasia, peaking during the 1400’s. Scholars of the time had many theories for the cause of the plague. Muslim scholars believed it was “martyrdom and mercy” from God, assuring the believer’s place in paradise. For non-believers, it was a punishment. Christian self-flagellants would whip themselves on the back with needle-sharp knotted whips three times a day for 33 days (relating to the age of Jesus) in order to invite God to show mercy. Medical masters in Paris turned to astrology, correlating the plague with the conjunction of Saturn, Jupiter, and Mars, under the moist sign of Aquarius, that took place in 1345, following both solar and lunar eclipses. The terrestrial cause was thought to be air poisoned from noxious gases released during earthquakes or rotting carcasses in swamps. [See here and here for more information]

Human Sacrifice
Throughout ancient Central and South America, Europe, Africa, and Asia, child sacrifice was an all too common means to appease the gods for any number of purposes: to ensure a good harvest, to win in wars, or droughts, or plague. For example, in the Hebrew Bible, the king of Moab is told to have given his firstborn son and heir as a whole burnt offering (olah, as used of the Temple sacrifice). Another practice, that of live burial, persisted from the beginning of mankind. Frequently, it was regarded as necessary to entomb within the foundation of a building, living creatures and even men, an act which was regarded as a sacrifice to the soil which had to endure the weight of the structure. By this cruel custom people hoped to attain permanence and stability for great buildings. “We read in Thiele (Ddiiischc J’olkssagcii, I, 3) that the walls of Copenhagen always sank down again and again, although they were constantly rebuilt, until the people took an innocent little girl, placed her on a chair before a table, gave her toys and sweets, and while she merrily played, twelve masons covered the vault and finished the wall, which since that time remained stable.” –P. Carus

How should we view these deadly misconceptions?
Before we criticize these ancient people for their seemingly barbaric practices, let’s put ourselves in their shoes for a moment (did they have shoes?). War was frequent. Systems of government and policing were weak if not non-existent, resulting in a might is right culture. Also, many of these issues revolved around illness. These societies were unaware of the causes of illness and therefore nearly powerless to prevent or treat those illnesses. Staying alive was a difficult endeavor during those times. There was frequent still birth, maternal infection, food insecurity, and disease (including plagues, dysentery, diarrhea, typhoid, cholera, etc. due in part to open sewage and unclean drinking water). Around one-quarter of infants died in their first year of life and around half of all children died before they reached the end of puberty [ref]. They had little alternative other than to pray and give sacrifice to imagined gods as means to protect or cure them from mysterious illnesses. It wasn’t until relatively recently that Ignaz Semmelweis and Louis Pasteur developed germ theory in the 19th century that we understood microorganisms to be the cause of disease. Also, many societies did not see death as a finality. They believed in an afterlife, so human sacrifice was not considered to be as cruel as we view it today. These societies were deeply ignorant of the laws of nature like weather, agriculture, and the basics of civil engineering. Imagine, Newton’s laws were not discover until the late 17th century. The neuron, the source of our thoughts, emotions, and behavior, was not discovered until the late 19th century. And DNA, the building blocks of what makes us human, wasn’t discovered until 1953.

Knowing how deeply ignorant these ancient societies were should give pause to sourcing one’s beliefs in the stories that have endured from these ancient times. Some beliefs were easily falsifiable, such as the sun being the wheel on Apollo’s chariot. Others are unfortunately unfalsifiable due to their nature. We cannot go back in time to prove Jesus was not birthed from a virgin and did not rise from the dead, but knowing those ancient societies were so often wrong should leave us, at the very least, highly skeptical. It would seem obvious we should not hold the beliefs from these times as absolutely true. For example, it is unlikely such deeply ignorant people had perfected morality. We heed no warning of the abominable shellfish, and most of us (at least in America) do not believe adultery and homosexuality to be worthy of death. And we know slavery to be immoral. Really, the Bible denounces shellfish, but couldn’t make it clear that slavery was wrong? In fact, it did quite the opposite – implicitly advocating for slavery by giving instructions on how to treat a slave and for slaves to obey their masters, etc.

It is not to say that science is infallible or has some monopoly on truth, but that we should give more weight to our recent discoveries and deeper understanding. And that we should practice those methodologies that rely on evidence and are open to and able to change based on new evidence. Take the ancient Roman aqueducts for example. They were an engineering marvel for their time, and what remains is still magnificent to behold. But, to think that a civil engineer of today should only learn the state of the art from that time in order to practice engineering is obviously absurd. I propose it as a similar case – the practice of determining morality and meaning today. Searching the Bible, Torah, Bhagavad Gita, Qur’an, etc., is to resort to sources deprived of modern information and understanding and motivated by superstition and desperation. We see the consequences of such beliefs when “Christian Scientist’s” children die when they aren’t given lifesaving vaccinations or treatments, when priests resort to pedophilia instead of allowing themselves to love another man (see below for some statistics), when women are forced to wear burkas or be “honor killed” by their parents or the “morality police“, when nations justify the extermination of other nations because they believe in the wrong God, and when suicide bombers kill a bus load of infidels in heroic ecstasy believing they are about to reach paradise. And tragically these ancient traditions still persist to today. Right now, child sacrifice is being practiced in Uganda. Right now, over 200 million women and girls in 27 African countries; Indonesia; Iraqi Kurdistan; and Yemen are subjugated to genital mutilation. 98% of girls in Somalia and 97% of girls in Guinea have had their clitoris removed because of an ancient practice to control a woman’s sexuality and maintain her purity. Female circumcision is not in a first tier religious text, yet most of us still find it to be reprehensible. To denounce these practices is to recognize the folly in holding onto the misguided traditions of our ancestors at the same time realizing a new secular morality can exist based on logic, facts, compassion, and reason.

10/9/22 Update: Here is some data on the extent of the sexual abuse in the Catholic Church. In the United States, there may have been as many as 100,000 total victims of clerical sexual abuse. [link] Outside of the US, in France alone, an estimated 115,000 Catholic priests and 3,000 other religious officials are estimated to have sexually abused 216,000 children between 1950 and 2020, and that accounting for abuse by other Catholic church employees increases the total number to around 330,000. Around 80% of the victims were boys. [link]