What do our sources say about "chiddush", novel ideas?
On the surface, how can one be "mechadesh" anything? If it is true then it is already written and/or passed down while if it is not written and/or passed down then it is not part of our tradition and one may not say it?! Many Torah scholars strive to be creative but this seems to fly in the face of our tradition. Christianity was "original". There is not one G-d but three [עפ"ל]. Islam was "original". G-d rejected the Jews and chose Mohammed as His prophet [עפ"ל]. These two religions may be original [the truth is that Christianity is rooted in pagan beliefs and maybe Islam is too but that is besides the point...] but they are also false and one must die before accepting the belief system of either one.
The sifrei kabbala emphasize the great importance of chiddush. One must not only learn but come up with new orignal insights [see Nefesh Hachaim Shaar Dalet for some sources and there are many others]. In Hebrew, the word for "original" is מקורי. The root of that word is מקור - source. The same word apparently means two contradictory things. Original means that it has no source? So how can the same word denote two opposites?
The greatest and most true originality is finiding original fresh insights in the source. It is not about inventing new ideas but revealing the new in the old. One is מקורי when he shows how this unheard of idea fits beautifully into the מקור. That is what we strive to do whenever we open up an ancient text. Read the words, absorb the ideas and try to uncover countless layers of hidden meaning.