Why did you think you were certain?  What led you to change your mind?

Most likely, we have all been wrong about something we were once absolutely sure of. After providing an example from your own experience, answer the following questions.  Why did you think you were certain?  What led you to change your mind? And, how do you know that you aren’t wrong about the things you are currently certain of? If possible, refer to the readings in your post.  (That doesn’t mean that you have to quote them.)