Knowledge vs. Conjecture

وَمَا لَهُم بِهِۦ مِنْ عِلْمٍ ۖ إِن يَتَّبِعُونَ إِلَّا ٱلظَّنَّ ۖ وَإِنَّ ٱلظَّنَّ لَا يُغْنِى مِنَ ٱلْحَقِّ شَيْـًٔا

And they have thereof no knowledge. They follow not except assumption, and indeed, assumption avails not against the truth at all.