Antonym to "procedural"?

I'm desperately looking for antonyms or somewhat opposites to "procedural". Checked on some antonym dictionaries but didn't find anything. More specifically it's about "procedural knowledge".

"Unplanned" or maybe "creative" could be some possibilities, but I wonder if something more appropriate could be found.

All possible suggestions greatly appreciated! Thank you!

Edit: Thanks everyone for the great suggestions! Together they led me to choose "exploratory" as somewhat opposite to "procedural". There's a huge variety of possibilities, but this one seems to fit my context well :)