[The following is a guest post from Jack.]
Here is a fun experiment in philosophy. But first, let me define my terms.
Philosophers speak frequently about justified and unjustified beliefs. What does it take to believe justifiedly? That is a matter of controversy. But it is often supposed that another way of saying that a belief is (un)justified is saying that it is (in)appropriate for you to believe. It may be appropriate for you to believe that God exists, even if He doesn't, if you trust your parents and they told you that He does. It might be appropriate for you to believe both that all doctors are older than 30 and that some physicians are younger than 25, if you have reason to believe each and you have yet to realize that doctors just are physicians. It is, of course, appropriate for you to believe that the Sun is round, that chairs are frequently wooden, and that there were dinosaurs on Earth once upon a time. Justified beliefs are supposed to be fairly easy to come by.
Now for the experiment: Have you ever believed something unjustifiedly? If so when, and what?
I have done this experiment a couple of times before, always with philosophers and always with the same results. After a bit of attempted remembering, the subject says that they cannot remember a single time that they believed something unjustifiedly. (Justified beliefs aren't supposed to be quite that easy to come by!)
Of course, you will have changed your mind about something at some point during your lifetime. Perhaps you even regret believing as you once did. That would presumably make it unjustified for you to believe today what you believed before. That doesn't make your believing when you so believed unjustified.
In any case, I wanted to do a little online survey to see if others have the same reaction to the experiment. Comment either way. If you think that you have, at some point in your life, believed something unjustifiedly, please say what you believed and why you think it was unjustified of you then to believe as you did. If not, what does it take to believe unjustifiedly?