﴿ إِنْ هِىَ إِلَّآ أَسْمَآءٌۭ سَمَّيْتُمُوهَآ أَنتُمْ وَءَابَآؤُكُم مَّآ أَنزَلَ ٱللَّهُ بِهَا مِن سُلْطَٰنٍ ۚ إِن يَتَّبِعُونَ إِلَّا ٱلظَّنَّ وَمَا تَهْوَى ٱلْأَنفُسُ ۖ وَلَقَدْ جَآءَهُم مِّن رَّبِّهِمُ ٱلْهُدَىٰٓ ﴾

“These [allegedly divine beings] are nothing but empty names which you have invented - you and your forefathers - [and] for which God has bestowed no warrant from on high. They [who worship them] follow nothing but surmise and their own wishful thinking - although right guidance has now indeed come unto them from their Sustainer.”

Various Types of Zann إِن يَتَّبِعُونَ إِلَّا الظَّنَّ وَإِنَّ الظَّنَّ لَا يُغْنِي مِنَ الْحَقِّ شَيْئًا (and conjecture is of no use in [ the matter on Truth.... 53:28) The Arabic word ظَن Zann is used in several different senses, and one of them is baseless thoughts. This is the sense in which it is employed in the verse, because baseless thoughts were the cause of idolatry. And the verse purports to remove the cause. Zann is also used as the antonym of yaqin. Yaqin refers to assured or definitive knowledge about something that really exists, not the figment of someone's imagination. In this case, there is no room for any doubt or suspicion, as for instance knowledge gained from the Qur'an and Prophetic Traditions uninterruptedly reported by an indefinite number of people or by such a large number that it is impossible that they should agree upon falsehood. As opposed to this certain knowledge, zann is sometime used for the knowledge that is based on a proof, and not on baseless thoughts, but the proof is not so certain as may rule out other possibilities, as for example, injunctions based on general narratives of the Holy Prophet ﷺ . The first type of injunctions is referred to as qat'iyyat or yaqiniyyat and the second type is referred to as zanniyyat. This type of Zann is recognized by Shari` ah. There is ample evidence in Qur'an and Sunnah of its recognition. The entire Ummah concurs that it is obligatory to act upon it. The above verse when denouncing zann, refers to the first type of zann which connotes baseless thoughts. Thus there is no contradiction.