Some follies are contagious, just like diseases and pain.
This quote suggests that certain foolish behaviors or misguided ideas can spread from one person to another in a manner similar to how diseases and physical pain can be transmitted. Just as we can catch a cold or feel the discomfort that others experience, we can also be influenced by the irrational actions or beliefs of those around us. The implication is that being in the presence of folly can lead us to adopt similar thought patterns or behaviors, often without realizing it. It serves as a reminder to be mindful of our environment and the company we keep, as we may inadvertently absorb their follies.
Author: C. S. Lewis