Let Papa Poirot decide.
Do facts matter?
They do.
Atleast that's what Agatha Christie told us, through one of her most ingenious characters, Hercules Poirot.
But if you truly know M. Poirot beyong his egg headed, big moustached countenance, you'd probably also be fairly acquainted with his little gray cells. And their working. ANd how they fairly subdue factual deduction. So, the question becomes fairly relative - to what extent do they matter? Over what? Logical deduction? Imaginative reasoning?
Facts matter to a gret extent, yes. Doesn't Poirot always demand facts before setting into his forte retrospection? Facts are the key to clever deductions. Fiction or non fiction. I guess, Inspector Japp would agree with me (the poor fellow went to great lengths to fetch facts for Poirot to ponder upon them). You see, facts present an idea before us - the actual picture of what truly exists or not. In other words, imagination is a derivative of fact. Imagine a red apple? Easy. Why? We know for a fact what red looks like; what an apple looks like. Hence, the ease.
That being said, Papa Poirot asks - how credible is your fact? 'The Earth being flat' was a fact for years until kind Mr. Columbus took the pains to prove otherwise. Facts must be proved. They must be backed up with credible evidences, or in the world of our wise Poirot, they must fit in.
At least that's what Poirot has to say.
Eh bien, facts matter.