We often want to stick with our current beliefs even when new knowledge seems to contradict them. This is known as the Semmelweis reflex - a dangerous phenomenon that has caused many deaths throughout history.

The theory is named after Ignaz Semmelweis

• In 1846, Ignaz Semmelweis had a breakthrough when he discovered that when doctors washed their hands before treating patients and delivering babies, it resulted in a drop in maternal deaths from puerperal fever to 1%.
• Despite his discovery, his teachings were rejected, he was sacked from the Vienna General Hospital. He became severely depressed and wrote open letters to obstetricians calling them irresponsible murderers.
• He was eventually lured into an asylum and died at aged 47. Twenty years later, Louis Pasteur carried forward his work. The germ theory of disease is now widely accepted.

The Semmelweis reflex is a knee-jerk tendency to reject new evidence. It's a form of confirmation bias where we deny objective evidence, even if it could bring transformative improvement.

We can train ourselves to avoid the Semmelweis Reflex by not holding too hard to our beliefs and keeping an open mind when faced with new data.