I think you could have written in the rules, that you want to exclude "imperatives" or sheer opinions. But this would have provided a valid distinction between belief, opinion, and knowledge.
I read your invitation in the sense of Kant, saying: "dare to know!" (sapere aude, Wage zu wissen) in its famous essay on the concept of enlightenment.
Therefore I hope you take a second start on this contest, explaining before what your aim is.